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Education is the process of diminishing deception
J. M. Nightingale - professor of control engineering

  

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Desoldering small transistors.
Where using a desoldering iron might dislodge fine tracks. Make up a 
needle point tool (described elsewhere in these tip files) but grind the tip 
flat. Push the tool tip against the leg of the trannie while momentarily 
heating with the iron and push through the board. Repeat on each leg.

Identifying B,C and E of unknown but good transistor. 
With a DVM with 
diode check it is easy enough to determine the base but which is E and which C.
Usually but not guaranteed as it is only variation in the last digit 
(metal mismatch potential etc ) but forward B-E 
drop is usually 0.001 to 0.004 volt more than the collector B-C drop.

Tip for blind persons.
I had a tape player, owned by a blind person, to repair 
that had mushy sound ,lacking 
volume and treble.
I could only assume a tape had been laid in a spilt 
spot of jam then transfered to the tape head. A large 
wadge of crud then built up. The owner regularly used a cleaning tape 
but it would not touch such an accretion. So tip to the blind 
is - opening the cassette door and with no tape in feel 
down into the mechanism roughly in line with the door hinge axis. 
In the middle is the metal tape head with 2 little protrusions 
that guide the tape so the width of the tape apart. Maybe 
another similar to touch 'head' offset from the centre that is less 
sugnificant.
The surface of this tape head should be polished smooth 
to the touch. So keep CDs,tapes,floppy disks etc away from 
surfaces that may be contaminated by spilt food.
A sighted person is likely to see if such material 
could be picked up but not the case for the blind.

Accurate RF sig gen
Use a wide band radio scanner loosely coupled 
to the output of a basic RF signal generator 
to find exact frequency of oscillation. With caution 
it would be possible to match to odd harmonics ( caution 
as harmonics could relate to sum & difference frequencies  to IF 
frequencies not I/P RF )

Source of high V and high C electrolytic capacitors.
Often discarded are basic film cameras with built-in 
flash. Usually has a compact electrolytic eg values
330V,280uF / 350V,350uF / 350V,330uF

Testing triacs
Adapt an ordinary room lighting dimmer by removing 
the triac and extending out to a shrouded socket for 
connecting the suspect triac. Wire up to a low wattage 
mains bulb and bulb socket. 
Will show basic low wattage functioning. 
May of course show false failures but have used to 
test TIC126, AC16D, TAG D3 420 400 with no trouble.

USA equipment with IEC mains inlet and line siocket 
lead to USA plug on other end.
Fine if the 240V to 120 V auto transformer is always there. 
But should someone unplug at the mixer then too easy 
to plug in a normal for UK IEC lead. Tie the IEC to USA 
lead intoi the mixer with rubber O ring and cable ties with 
a large label saying 120V, should be  abetter reminder.

Identifying segments on multi-backplane LCD displays
Drive LCD from an af generator about 80Hz and
about 3V pk-pk square wave. Too high a voltage and
extra segments light, too high f and too feint and
too low f then flickers. If LCD is removed from 
a pcb/micro then doing a DVM "resistance test" 
between drive lines and ground may show 
a difference in 'resistance' between backplane 
lines and segment lines.

Innards of ganged multiway slide switches.
Remove whole switch bank - easier said than done.
 Makes sure no bent pins,blank off external area and 
heat with hot-air gun to desolder.
Remove the errant slide switch by bending back the 4 
horns that hold to the cross-way but remove the 
return spring that returns the metal slide latch bar 
that is inside this connecting channel or it wil spring off.
Then removing the large spring and associated plastic 
mechanism the switch slideway will  then pull out.

Feint impact printer output.
Assuming dried out cloth printer ribbon rather than 
worn out film ribbon. Remove the cover and 
squirt WD-40 inside and allow to soak well in. Output 
a large text file to run the ribbon through a bit before 
using in ernest.
If sealed then make a hole , squirt and cover hole again

Too short a cable-tie
Join 2 or more together in a line "pointing" 
in the same sense.

Where it is necessary to enlarge a mains cable entry hole 
to take a larger cable anchor. To save trying to make a D hole. 
Enlarge to required diameter and then get a piece of metal strip 
eg flatttened chassis mount capacitor clip and bolt near to hole, 
cut to length and bend around and into the hole to make an 
anti-rotation D shape.

Colour coding eyelet and prong type crimp connectors 
for DC use.
Paint or dip in paint "blue" ones to give red or "red" ones 
in black paint say

Reconditioning ganged multiway push switch banks.
As found on tuner preset switch banks.
Remove whole assembly from pcb. 
One-by-one bend back the metal retaining horns. 
Pull the sliding plastic part from the plastic housing 
for each switch but beware of internal spring.
Dab some graphite grease (ITF) on each phosphor bronze 
contact. Use fingertip assembly turning each contact with a 
needle point (ITF) to align with fixed contacts  before pushing 
back in place. Then place back in the metal frame. 
Check alignment with the latch matrix plate 
(switch functioning electrically and mechanically) before 
and after bending back the mounting horns.

Chucks on Dremmel / minidrills.
I sometimes find a small <>1mm or so drill or shaft that does not fit the chuck 
properly. For these very small drills it is possible to slide some plastic 
or rubber sleeving onto the drill and then squash in the oversized chuck. 
A better job is a cut down QM or Trident socket pin or 
whatever is suitable. Avoids having to change the Dremmel chuck.

PCB repair after burnt component has burnt the board as well.
With Dremmel and ball mill cut away all charred material .Make sure the hole 
is "bevelled" on both sides to key in the filler. Use some epoxy 2-part with some 
small strands of chopped fibre-glass matting. Cover one side with some upholstery 
to produce a flat surface and squash the filler with a piece of plastic etc covered with some 
plumber's PTFE tape.

Working on small equipment with tiny screws etc such as Walkmans.
Do disassembly / re-assembly over a tray with serious side walls and 
base covered in felt so any dropped parts aren't likely to bounce 
out of the tray.

Testing crystals,ceramic resonators and filters
Signal generator (RF) and scope. Connect the grounds together 
and then connect the sig gen to the scope via the crystal.
Sweep the oscillator and resonant response at fundamental 
and overtones will show on scope trace. Use a f counter 
as well if f is required. If testing while 
in  circuit (unpowered) use less then 1V sig gen o/p . 
The response may be muted comnpared to free component 
especially for ceramic resonators.

Loose insulation tape.
After wrapping with insulation tape, partly melt the 'free' 
end into the rest with a soldering iron.

Something to keep a kid occupied on a wet weekend
Obtain a dumped VCR (older the better) and get little Johny to take apart 
to the last screw and washer.
Safety note cut off the mains lead should he think of powering up,
powerful magnets inside so could nip fingers also sometimes 
strong springs that need to be released carefully and some 
screws and circlips may be beyond strength or dexterity of a kid.
Interesting bits to be found inside that can be instructively re-used. 
Motors and solenoids usually about 12V,pulleys,belts and cogs. 
Often a compact reduction gear train attached to one motor.
Infra-red LED transmitter and reciver.
Dew sensor (humidity) usually Aluminium plate screwed onto the base 
of the video head assembly - holding usually white ceramic with dark grey 
square on it or green epoxy lump with 2 wires coming from it.
Put on a DVM and breath on it.
Inside the capstan motor often 3 Hall effect sensors that would 
need desoldering. Put about 5V on the pins that were paralleled 
together on the pcb. Or find pair of pins with DVM diode 
test with low forward drop in either direction to find the 
power pins (assuming 4 pin variety). Monitor the voltage 
between the other 2 pins with moving magnet.
Observe the video heads (my pictures) under 
a kids microscope and imagine 
how those turns of fine wire are looped through that tiny hole.
Count all the bits and pieces that make up a VCR

Macrophotography with microscope and basic digital camera
 Modified the camera for remote trigger/shutter release ( see 
repair4.htm file) to avoid camera shake.
I started with an ancient Watson Barnet stereo viewing 
microscope, with x5 double objective and 2 x10 eyepieces.
Unscrewed one of the eyepieces and fixed over it a 35 mm film 
storage pot, with base cut off. Padded out with rubber 
pulley tyres. Did the same with padding out the boss of the 
camera lens at the othe rend. Fixed the camera to the microscope so it 
could not be knocked off.
For dark subjects shine a pre-focus torch bulb through the 
other lens system. Put this bulb on a draughtsman's bendable curve or 
one of those silly pig's tail drinking straws with deformed 
concertina section so will take up any XYZ position.
I found the camera image was a circle diameter 3/4 of the smaller axis of 
the frame.

To enlarge a boot for rear of mains connectors etc
Needed to make a boot for a combined IEC chassis socket and fuse holder 
but only standard IEC boots available. A retort clamp from a chemistry lab has 
claws that will close and open under screw thread. Jam in the boot and open outwards.

Refixing broken pivot type tape player function keys.
The type where 4 to 6 keys are in a line 
and pivot on the one rod.
Heavy-handedness/age brittling and the clip 
part that wraps or part wraps around the rod 
can shear. Make 2 slots in the plastic of the key 
near the rod and 2 notches or holes at the other 
end of the key/knob/button. Pass 2 small cable-ties 
around and tighten so 2 loops replace the broken bits 
of plastic.

Testing near Farad capacitors used for memory retention purposes.
With demounted cell starting from discharged state. 
Charge up with a DVM set on diode check (corect polarity) . Then 
disconnect and set on volts range.
If on charging the "forward volts" doesn't 
slowly increase so it jumps up to 1.5Volt 
say and quickly drops when "loaded" by 
the voltage check then useless.
Data for good .1F dropping by about 3mV per minute 
for first minutes starting from a "charged" voltage 
of .6V after about 30 seconds charging.

Poor edge contacts on ceramic sub-board/ duaghter boards.
Often painted black with epoxy paint. Abraid & scrape off 
paint from the contacts and nearest section of ceramic to expose 
the copper of the tracks, not always on same side. Solder across 
with fine tinned wire.

Replacing ICs
After desoldering the errant IC solder in a turned-pin socket (assuming there is space/ height) 
so should the real reason for it failing not be apparent you don't have to desolder the 
replacement IC.

High voltage batteries for high resistance scales of old meters Avo,Taylor etc
Use one or 2 15V small photographic batteries. Butcher the batteries to reconfigure 
or enlarge the housing to accommodate or mount externally to the meter casing.

DVM resistance checks in the presence of Schottky diodes
As found as high f rectifiers in inverter type supplies.
Forward diode voltage of Schottky diodes are about the same as the probe 
voltage of DVMs in resistance range. The DVM will register a "resistance" in 
the presence of such diodes. This "resistance" varies with the range setting .
eg 200 ohm range "registers" say 150 ohm,2K reads 1.8K,20K reads 3K and 
200K reading 8K.

CD player test CDs
1) For checking whether there is any IR emission from the laser.
Any old scrap CD including CDROM (Seedy ROM) . Chain drill a radial line of holes from about 
"track 2" to final track. Clean up with a needle file. In use, use in conjunction with the 
photodiode + LED zapper checker described elsewhere in these tips files. Don't use 
if it looks as though the lens under servo action could hit the surface of the CD.
2) For checking error correction /immunity to errors.
An out of favour audio CD but otherwise in perfect playable condition.
With an assortment of potentiometer back nuts and washers ,small motor 
pulleys find a combination that will "fill up" the hole in the centre of the CD leaving 
just a small hole at the very centre> With a set of "geometry" dividers put one point 
in this hole and lightly scratch a gouge about halfway along a radius of the CD and about 1/4 
of the circumference at that radius. Remove the washers etc and play on a known good player. 
Repeat the groove cutting deeper/wider/number of nearby grooves until one track 
or part of that track fails to play.
Make a note of the track number and start seconds and finish seconds
 into the track/sections of track/s that are absent.
For your own machine every now and then (months) play and note the numbers to note 
long term drift. More absences/ longer absences over time indicates deterioration in optics /
correction . Use the same CD for checking in CD repair of other machines and crude adjusting 
of optical power etc.
3) Make a single tone test CD via computer CD writer. Some software has a facility for making an 
audio test CD. Failing that feed the line output from a stable audio signal generator into the PC. 
Principle tracks would be long track of 1KHz left and right,then tracks of 1KHz left only,1KHz right 
only then both channels again with frequencies of say 50Hz,200 Hz, 1KHz,5KHz,10KHz 15KHz

For a new batch/make of recordable media 
Burn the same data at the minimum , maximum and 1 or 2 intermediate speeds
on 3 or 4 discs, label them specificaly for their ?x speeds for later
checking on environmental degradation/ data corruption. Look at 
them together with an oblique light source.
If there is an observable gradation in the appearance of the 3 or 4 discs
on first such recording test then use a lower speed setting for recording on all the rest of the
batch/make.

Cleaning CDs, DVDs etc
Always clean
data/audio or video CDs in a radial sense, not circumferentially, so that
any microscratches are across and not along the data paths.

Static-electric shock avoidance
I am surprised so few people know of this tip for where they regularly get
static electricity shocks from walking across carpets.
Have a key or coin between the fingers and touch the locker or whatever with
that first and it distributes the current so although you may see the
discharge you don't feel anything.

Thermo - chromic indicator (re-usable)
For monitoring low temperature localised temperature increase.
Unfortunately this is for UK users only. The 2001 issue of commemorative 
postage stamps for 100 years of the Nobel Prize ,19 pence issue 
for chemistry, has thermo-chromic ink on the central (buckyball?) 
design, black at about 15 degrees centigrade 
varying through grey to white at about 35 degrees C. Preferably used stamps 
and put a gummy surface to the back to stick to ICs etc. Cut up and stick with 
blue-tack (sticky poster putty) to power trannies in amps to monitor irregular 
current passing (over or under).

Treating perished rubber drive bands
I pass on this tip from someone else without personally trying and i don't know 
what he meant by perished (going hard or soft). Place the band in 
boiling water.

Opening cases that have been plastic cemented closed eg Ni-Cad battery 
packs. Squash (long ways) in a vice or if not long enough a sash cramp or G-cramp until 
the seam bursts partially. Repeat in the cross sense which may or may not have an 
effect. Open up the split into the corners etc by forcing in something like an old 6 
inch steel rule then another such ruler. Then with twisted screwdriver blade between the 2 rules 
you can extend the crack without messing up the plastic.

Non- electronic shops for odd materials and adaptable parts:
Angling / fishing shops have medical forceps ( for heatsinking/ component 
placement etc ), very small latex rings,PTFE fittings, very small bore 
non-ferrous crimps, silicone rubber cord (short lengths make adequate replacements 
for those annoying little , easily lost, springs that force out tiny ball bearings 
in slide switch and sliding pot detents ), "ghost cocoon"/whippy elastic very elastic 
and strong for its size retains elasticity after being taken to 220 degree C 
and melts something less than 370 degree C, unstretched is about 0.5mm diameter
UTS about 500gm and elasticity about 20 gm to double the length, elasticity
and integrity survives 220 degree C; very fine bore silicone tubing,silicon sleeves,fine braided wire, "diamond" twisted 
wire "mouse" , for pulling line through fine rod tips is useful for creating 
silicone sleeved cables for pulling wires through the sleeving, 
spring balance for measuring tension.
Traditional hardware / plumbing suppliers for 'O' rings.
Silicone rubber cordage is used, these days,  
by commercial companies roasting chickens to 
bind the legs together while roasting; "Silicone bakeware" from kitchen utensil shops for  
a source of sheets of silicone capable of withstanding 220 degree C.
Industrial plastic sheet suppliers will often give samples - i hate to think 
what a 6 x 4 foot sheet of PTFE would cost.
Car spares shops - captive nuts and similar fixings.
Vehicle tyre fitters for used rubber inner tubes (drive bands)
Garden supplies have small copper sheet plant lables, eg Gardman, also Haxnicks/Haxnick's 
"soft tie" could be used as a rubber sleeving, remove the wire . 2 sizes for 
about 5 GBP each so expensive but iff you stretch the rubber, it stays 
at a smaller diameter and is very strong( not very centred bore though.
Hobby/Craft - diamond faced small cutting discs, small tubular glass beads for covering 
fuse wire for tiny fuses,  Hama/Perler/Pearler beads (small 
coloured plastic rings) for making "mosaics" on a sort of pegboard, 
many uses including colour coding very fine wire, (darning 
needles to make needle-point brobes ), Hobbycraft & Aldi (sometimes) now do coloured hotmelt sticks and model / remote control model shops 
for heavy duty rubber bands that can be dut down to smaller widths, wide 
heatshrink, etc.
Boat Chandlers for cordage and bungee for sheething simulated 
cloth covered wire, "rescue tape" for high temperature adhesive tape, 
stainless steel fittings and fixings, GRP woven glass mat.

Measuring force of springs.
Compression - push against a kitchen balance with weight scale.
Tension - add a weight with attached ring to the scales and then 
attach spring to the ring and pull for reduced weight.
Torsion - twist the spring against the ring on the weight 
at an appropriate radius.

Poor man's loctite: nail varnish

Stereo cassette heads
Replacing some heads with non standard orientation of pins I had 
to determine what was the standard layout of the normal stereo head.
With cassette head nearest to you and spools away in normal forward play 
the left channel is the head nearest the body of the deck.
In the same vein; if you manage to swap leads around in piece of kit, 
cassette player ,CD etc and can't be sure whether you have swapped 
left and right channels. Play a piece of properly recorded classical music and 
the violin section should be left-stage on the left channel.

To avoid slipping with DVM or scope probe and shorting between IC pins
In the UK find a Molex conector just the shroud. It must have thin 
dividers between each section where the pins are inserted. Drill small holes 
just back from the edge. Cut through 2 slots cuts each making small slots 
divided by thin dividing walls. Cut off surplus major part of the shroud. 
When placed over a line of pins of the IC and probe / prod put in these small 
slots it cannot then slip. For fine pin-spacing ICs use a couple of 
pieces of mica washer.

Anti-static conductive wands under cars.
Don't mount vertically down or it will just wear down.
Mount angled down so the tip is just touching the road 
with no one in the car,not vertically down. Or mount swinging 
,not rigid. Otherwise it will soon wear down - it is only 
necessary to make contact when the car is stationary.

Hint for making three spoke screwdriver for Nintendo etc
That is for the screws holding the case of Gameboys.
They are like philips head screwdrivers but 3 points instead of 4 points,
possibly trade name Tri-Wing (triwing/tricorn)screws.
Start with a 2mm across flats basic Allen (Hex) key.Form the 
"screwdriver" on the end of the long section of the key.Hold in 
a pair of Mole-grips (Lock-jaw pliers).Then under a magnifying 
inspection lamp grind flutes into the Allen key.That is every other flat 
grind a flute with a thin grinding wheel or diamond/tungsten faced 
wheel in a Dremmel. Then open out these flutes to cut into the adjascent 
flats leaving just the central section to engage in the 3 screw slots.
Then grind a slight chamfer on the end of each spoke to match the internal 
form of the screw heads.



A professional job would case-harden by heating the key and dunking in 
Casenite (carbon rich) powder to harden the ground surface. My smallest 
Torx screwdriver made in similar fashion 10 years ago is still in service 
without case hardening so not really necessary. This Torx driver started 
as a 1.5mm across flats Allen key and grinding a flute in the centre of 
each flat.
For srews with triangular recess in the head then start with an oversize 
allen key and gradually grind every other face until it seats 
into the recess.
Some data for the smaller sizes of security screws etc 
(from measurement , not design parameters)
Clutch C1 size, 3.5mm across the blade
Spline M5 , 4.6mm across splines
TORQ GR6 , 5mm across , form is 4 non-radial flats arranged around a 2.2mm 
central square.
Torx tamper, T8 2.2mm across splines, pierced
Torx T8 , 2.2mm across splines 
Torx T6 1.5mm, T5 1.3mm
Pierced blade SP4 3.8mm across slot driver blade, 2 dog.
Square R0 1.7mm square
Tri-Wing 1 ,1.6mm offset diameter between wing and opposite of centre at the tip
Philips 0 size point centre is 1mm across
Pozidrive 0 size has 1mm across centre point

Opening 2 part plastic boxes.
As used in external modems etc where holes emerge in the base showing 
the interlocking nibs at the junction. Push a screwdriver in slot and lever 
the handle of the driver in an outwards sense to lever the locking piece inwards.

A tip for the repair shop.
Every now and then you are in the midst of a delicate re-assembly job 
etc and the phone goes. Of course it is easy to previously take the 
receiver "off the hook" ,the problem is remembering to replace it. 
With a small piezo buzzer + battery + tilt switch wire up and mount 
on the receiver so when upside down say the buzzer sounds but not when 
on cradle.

Lacing cord to reinforce broken plastic bosses etc.
That is plastic cogs etc where the teeth are OK but the boss has broken 
where a pin,flatted shaft or similar goes through. Find a small vice with holes 
for mounting soft jaws or the holes for mounting on a workbench.
Cut some lacing cord (used for tidying and tying up in wiring looms).
One or 2 turns of cord around the boss then half a reef knot. Tie the loose 
ends to the holes in the vice and stretch to tension. Coat in glue and cut when 
cured. Perhaps repeat the process again if there are no space constraints.

(Non) De-gaussing of TVs
For convenience of access I repaired a TV on its side. Come 
to powering up there was horrendous lack of colour purity 
on the periphery of the image. Eventually I twigged it 
was due to changed relative orientation of the earth's 
magnetic field and I had not allowed time for the thermistor 
in line with the de-gauss coils to cool down so not coming into effect.

Sulphated car battery.
Resusitated enough to take charge. Assuming there is top access to the cells .
Find a hacksaw blade,cover end with some cloth tape. Push in between plates 
and work back and forth to scratch away some of the sulphating. Wear gloves ,goggles  
and protective 
clothing to avoid the sulphuric acid.

Replacing mains inlet cable strain relief grommets.
Two part plastic 'grommet' that locks into flatted circle chassis hole.
Place grommet around cable and squash across internal surfaces 
with 'mole grips' tie off with tightened lacing cord before removing 
mole grip pressure. Remove lacing cord after inserting through chassis.

Variable volume phone ringer.
For someone pestered by people ringing his number by mistake from 
the USA so in the middle of the night here and he could not 
change his phonenumber. Many phones with piezo sounder "ringers" 
have a switch to switch off the ringer but the problem is remembering 
to switch it back the next morning. Put a 1Megohm preset across 
the pins of the switch so he could adjust the volume in the "off" 
position to be quite enough not to wake him at night but loud 
enough to alert him daytime if not reverted to normal. If site is 
light enough in daytime and dark enough nightime then a LDR 
in line with the sounder may be a neat solution.

I am getting a bit tired of seeing TVs and VCRs where someone has tripped over 
the trailing lead to the aerial  socket. The connection to the tuner is then broken in 
the process. Make up a simple adaptor of a small length of coax with plug on 
one end and socket on the other and plug the aerial lead into this. Not having the 
right-angle connection to the back of the set gives a chance for the lead to disconnect 
without damaging the tuner.
You also have the option of making a loop or two of the short add-on lead, around a 
cable tie or similar, to anchor to a firm bit of chassis or casing

Making a nut driver for bush nuts especially for large 
mixers where there may be 200 nuts to remove from 1/4 in sockets.
Need the nut driver from a  1/4 socket set and sockets from 
a 3/4 inch set as only they are large enough, but not usually 
includes an adaptor that way round.
With a 1/4 in for 6mm or so socket grind 4 small orthogonal flats 
on the "6mm" end to match the 3/8" square recess and 
use as an adaptor.

Mylar speaker cones.
As used in external environments: door entry phones,marine 
transceivers etc.
Not always possible to find the right size replacement for 
one where the wires going to the voice coil have corroded 
away. Use a cardboard cone one but cover with hot-melt glue. 
Using the gun squeeze out glue on centre of cone and spirally 
out to the periphery and then with an old soldering iron melt 
into a continuous covering of hot-melt. Hardly hi-fi quality 
sound but it never was in the first place.

Vacuum assisted desolder tool on the cheap.
A common problem with the professional vacuum assist desolder 
stations is they are fine until the heater element fails then you find 
the model is obsolete or phenomenal price for a new element.
Start with any old basic desolder tool with heated metal end and 
hand actuated spring action sucker. Remove the plunger ,put 
in some fibrous wadding for a filter and connect 
via a tube to a solenoid operated valve then to  a "vacuum receiver" 
made from an empty small butane bottle and a bit of plumbing.  With a 
vacuum receiver it 
is not necessary for a high grade air pump. Use the air inlet side of 
an aquarium aeration pump or even a domestic vacuum cleaner for source of 
low grade vacuum to reduce the air pressure in the receiver to 
maybe only 0.8 atmosphere. Use a foot 
switch to activate the solenoid valve .

General CD info.
In normal operation the rotational speed of a CD on track 1 is about 26 revolutions 
per second down to about 15 revs per sec on the last track.

Clips for heatsinks.
For the situation where you have an electically equivalent replacement 
for a power transistor or power handling IC but physically the 
mounting holes in the heatsink don't match-up. Use a Terry clip (spring clip used 
for fixing handle of hand tools to tool racks / shadow boards). Part 
of the clip may have to be cut down with hand shears to pass 
between the vanes of the heatsink.

Human failings and amplifier to speaker leads.
2 amps in 2 weeks for repair due to the following reason. Great heavy duty 
leads that you could run an electric cooker off. In one case insulation 
stripped back too far and conductors crossing and in the other 
spreading of multi-stranded wires and making contact when moved for 
cleaning. I don't get involved with arguments about oxygen-free 
copper,gold plated terminals etc for audio situations LOB as far as 
I am concerned. Terminate these 
leads with "yellow" crimp eyes or hooks large enough to go on the 
terminals and paint each of a pair red and black. Another person 
previosly complained of amplifier with wavering stereo image,problem 
only being reversed leads to one channel.
Why do amp manufacturers not seem to realise that many owners have 
amps wedged into awkward places ,with no lighting and fiddle 
with the speaker leads when powered up. I would have thought it would be 
standard practise to surround the speaker lead terminals with some 
clear plastic sheet to avoid stray bits of wire touching the chassis. Very 
basic modification to existing amps is punch a series of undersized holes in 
some celluloid and fix around these terminals.

Pre-emptive action on croc-clip test lead sets
That is the cheap bits of coloured wire with a crocodile clip at either 
end. Invariably the wires are badly crimped into the metal-work. At some point 
in the future these "joints" will fail. When new solder the wires in place.
Open the clips onto some wood to remove the covers and solder at the 
anchor points and recrimp melted sleeving.

Using a medical stethoscope
I've previously only used one with the diaphragm replaced with a length of
polythene tube to discover where squeels or squeaks were coming from in
mechanical equipment.
This time a bass speaker that was making rattling/scratchy noises when
driven with sub-100Hz feed.
Nothing wrong with cone/gluing/skirt/spider etc and fingering the driven
cone (wearing ear defenders) made no real difference to the random rattle.
Could only summon it to order by placing the cab on its side, otherwise in
band use it would appear intermittently.
Decided to listen with the stethoscope , with diaphragm attached , while
driving with 60Hz, not deafening as presumably because not tuned for
sub-100Hz.
Rattley/scratchy noise was then noticeably prominent in one area of the
speaker frame mounting.
Removing again from the cab , there was a length of unglued and uncompressed
foam, about 4mm at widest, around the mounting flange that must have been
resonating and flapping against the frame.

Close up extension tubes for a Canon A1 camera lens.
In the UK anyway plummers PTFE tape comes on white reels with an 
outer cover that clips on the reel. The lipped end of this cover slips neatly on 
the mount of the lens part. Find another such cover and cut into the unlipped edge. 
This will then sort of fit on the camera mount. With a stout rubber band wrapped 
around each of the two plastic rings place together with 4 matches bridging the 2. 
Hot melt glue the 2 rings together. Remove matches etc and paint inside and out with black paint.
Cover the cut with some black tape and push a stout rubber band over to give 
some sort of grip to the camera body.
Set the lens in manual stop down by paring down a piece of match and 
wedge in the slot with aperature stopped down then use the aperature ring to open 
for focus and stop down for exposure. Make a ring of wire 
with 2 small lops  to wrap around the base of the 
lens between the 2 rings on the mount. Tie back the lens to the camera strap anchor 
points with stout rubber.

Renovating/reconditioning irreplaceable pots.
The type where the end of the shaft is swaged at the end and needs to be 
undeformed to break apart to get to the interior. Made of aluminium these 
little bits of metal usually break away. To replace the end platelet deform 
the end of the spindle with an automatic centre punch set at a very light 
setting of the spring action enough to burr outwards to retain the platelet.
For dual pots - beware when bending back the aluminium tags to 
separate sections , the reaction force of a twisting screwdriver blade 
may deform part of the fixed section. If this happens the bent bits 
internally may interfere with the rotor so force back with the end 
of a screwdriver or steel punch ,pushed not hammered.

Confusing K resistor marking
eg 6.8 (Greek omega ) K , meaning
6.8 ohm not 6.8K, the K is the tolerance value in this usage
 confusing K resistor marking

"Conserving" frayed and browned acidified paper of old books
I cannot vouch for the long term effectivness of the following method. I will 
update or remove this tip in a few years time. As of writing initially 
this tip, July  
2001. I have a number of data books and service manuals from the 1950s 
onwards where the paper is going distinctly brown and friable around the edges. 
In another 10 years they will probably have disintegrated to dust. There is 
a proper archivist, patented ,commercial process, for doing whole library stock by the pallet load 
but too expensive. That is done dry using  a vacuum chamber and a secret mixture of 
chemicals and insecticides introduced, spirit based so no damp paper involved. 
I am only interested primarily in the info not the books 
themselves so if I destroy in this process then I have only accelerated the 
destruction. The first process is to make a good photocopy of the book in case 
the following method doesn't work.
Do a test on one page to check for fastness of the ink. 100cc of paste solution 
does about 100 single sides of pages. Mix in volume ratio 2:2:1:20 of wallpaper 
paste powder,washing soda ,Cheshunt Compound and water.
Cheshunt compound, to avoid possibility of going moldy, it 
is used by gardeners to stop "damping off" and is w/w 85 parts 
ammonium carbonate to 15 parts copper sulphate. 
Allow to gel-up. Then on every other 
page say 1,3,5 etc for half the book at a session brush paste one side of each page. 
Turn each page before brushing on solution.
Do not overbrush to reduce possibility of dislodging ink. 
From cut down thin plastic(eg supermarket carrier bags) cut to page size pieces 
and place interleaved . 
After a couple of hours, progress through the book flattening down and 
outwards and pressing by hand to deal with the worst of any rucks. 
Then do an initial press between boards and a large vice or 
plates and threaded bars plus nuts, until cannot tighten any more 
and then undo and start the drying out process.
Initially every few hours after pasting ,turn the pages to 
avoid sticking. When dried after a couple of days do the remaining half of the book 
or just rely on some migration over time and leave at every other page. 
When totally dry put in a press/vice to flatten out. Assist drying with a fan heater 
blower with heaters switched off. In practise (may vary with types of paper) when the 
plastic sticks to the paper with a little adhesion it is possible to remove the plastic 
sheets totally to quicken the drying process. Overnight repeat the 
pressing is better than one final pressing and if using every other page 
processing then will act blotting paper fashion, loosen the pages 
after pressing before continuing to dry. Increase the pressing 
force over time perhaps. 
Using a drop of universal 
indicator an apparent pH of 10. Three months on now still pH 10 so next time i will 
probably dilute a bit more. A year on ,July 2002, tested and still pH 10 ,also the seriously browned 
edges to the sheets are more fawn than brown now. 
I did not think to leave a page untouched for before 
and after but I would say the paper is more cream than brown now. Some red ink 
did not fare well it is much feinter than before. Treated pages 1,5,9,13 etc only. The pages 
of my original 1950 databook done July 2001 show 
about 9.5pH, two years on March 2003. May 2004 and Oct 2006 the pH of this 
first treated valve data book is still about pH 9.5, 
black ink is less black than originally. October 2004 about pH 9, there 
is a thin dark brown edge to the paper now but this is also pH 9; 
August 2005 still pH 9.0, same June 2008.
The paper feels more supple ie less brittle than before treatment, 
no trace of continued edge fraying and the central area of paper seems to 
get whiter over the years but maybe the ink gets less black. This wet process messes up 
the spine so I now clamp the spine between 2 wooden battens bolted together and try 
to avoid the wet solution collecting in the gutter area, just saturating the ends 
which are the brownest from airbourne SO2 / 3. While the pages are still damp but 
not so damp that they stick together and with the spine still clamped press the body of the 
book overnight between a pair of boards (covered in plastic to avoid sticking ) and clamps 
made from a couple of 10mm threaded bars, nuts and stout flat bar or 
channel with holes to suit the studding (2 back-to - back lock nuts on each rod 
and tied across with a couple of bolted together tie bars). If pressing 
more than one book interleave each book with some 1/4 inch non-ferrous plates.
I talked to a local professional document conservator. They use 
magnesium carbonate. It doesn't readily dissolve so they put it in 
a soda siphon to bubble CO2 into it. Then use the solution to de-acidify and 
proper tissue and wood pulp to reinforce but that is single sheet processing for ancient documents.
I will carry on using my technique. A non water based proprietory 
solution has believed trade name Whetoo.
 Any ideas for simple fixing of loose pages and broken spines anyone ?.
 
Some further reading on book conservation 
For paper that is still more cream than brown then use the following easier process.
Use a household hand spray-gun to spray a mix of 30gm washing soda,5gm Cheshunt 
Compound to .5 Litre of water. Place the book in near vertical position 
inside a propped up rectangular plastic washing-up bowl to localise 
the spray. Place a grid or something under the book so it doesn't sit 
in a pool of surplus liquid. Spray 2 sides then turn 2 pages so spraying 
pages 1,2 then 5,6 etc and when complete leave the book in 
a vertical position with pages fanned out as much as possible to dry out.
For saturated books (dropped behind shelves into a damp part of a shed)
 that have since dried out into a solid 
block start by totally soaking again.
Use a bevel edge wooden ruler with the corners rounded to slide 
in-between pages to split apart , maybe fraying a sheet at the edge to get 
started.
Another conservation tip - dealing with paper that someone previously 
has repaired tears with sellotape/sticky plastic tape.
Often goes even more brown than the rest of the paper so cannot photocopy. 
Remove the tape with a low-temp hot-air gun and neutralise 
the remaining gum on the paper with talcam powder.
Update Oct 2005. Car wash spray kit made by "Flash" 
powered from mains water hose may be suitable for these purposes 
if washing soda soulution is filtered and added to shampoo bottle - 
I've not tried. Also from a conservator a freezer can be useful 
for cleaving pages of  water logged books - again I've not tried.
For large books say 1000 pages, 2 inches thick, Get some basic 
drinking straws and fold in half, place every 20 pages or so so 
1 straw every 40 pages bind round with a large rubber band. 
Cover the book covers with plastic bags. Bind the spine with lathes. 
Use more dilute washing soda  
solution about 50gm per litre plus Cheshunt. Fill a trough or 
large stout plastic bag and place book into soulution up 
to the lathes for only a minute or less for reasonable wettage 
or longer if thorough soaking but large books can take up a lot 
of water like this and 2 inch thick can expand to 2.5 inches easily so 
avoid soaking the gutter area. So far they've dried out without problems but 
glossy paper may be a problem. Can appear like a solid block of 
wood but curving the pages in a block as in flicking through 
pages ofa book will break the 'adhesion'.  I've also recently tried just dunking 
book , without straw spacers, overnight and solution only 
penetrates a few mm around edges but as this is where most SO2/SO3 
damage is it may be sufficient for minor acidification.
Found a fine spray pump up garden sprayer but 
all the "o - rings" needed replacing with proper 
O rings and a rubber washer placing between the 
two brass parts of the nozzle to stop drips at that point.

Another tip for paper archives
That local archivists to me were not aware of.
Old type index cards, in drawers, are often removed and 
misfiled on replacement.
With a range of colours of broad tipped felt tip pens 
run a diagonal line or more (different colours) across the top of each rank of cards, 
different colours for different drawers or dates or whatever.

Avoiding potential disaster of DMM/DVM use
The chance of mistakingly using a meter set for current monitoring on live kit ,
thinking you are measuring voltage.
Its not the blowing of a meter fuse that I'm concerned about. Its shorting
some expensive bit of otherwise working kit that I'm wary of.
I've not done it for a long time but there could so easily be some time in
the future, probably pushed for time, and there will be a big flash and a
bang.
Someone, like me, using the same DMM day
in day out, 99.99 percent of the time for other than current, may accidently
go to use this meter , still set in amps mode, for measuring volts , just
because it is so ingrained in using it for such purposes.
A 5 minute job and peace of mind.
Every day used 
Fluke 77 , now with hot melt glue down the 2 current sockets and a dollop on the
rotating function switch surround. so it cannot be turned to A dc or ac.
A dollop of hotmelt in the "volts" socket of an old meter and a 2 croc-clip
ended leads, instead of probes, so very unlikely to absent-mindedly use
that one in volts test mode.

Replacing mains cords that pass through moulded plastic cord 
protectors as used on backs of VCRs etc.
Cut away old cord,remove plastic insert from the casing 
and on the underside hacksaw or cut to split and remove 
the remnants of the cable. Reuse wrapped around new cord 
and anchor on the inside of the cord protector with a 
substantial cord anchor rather than just a cable tie.

IEC socket with integral fuse.
To pull out the fuse carrier to inspect the fuse , 
psh a small thin blade along the edge/s of the carrier 
to push back the internal end stops. 

Bulk metal removal in awkward positions.
Where adjascent surfaces don't allow the 
use of files or hacksaw.
Obtain a few engineering endmills and use the fluted 
parts when mounted in a hand drill.
Preferably workshop throw-outs where 
one of the proper end tips is sheared off.

Valve Cathode / Heater leakage
Was I wasting my time , rather than throwing out some ECC83, a 6V6 and some
EL34 and EL84.?  All various degrees of C/H leakage causing
vibration/tinging sensitivity so useless despite useful gain.
All measured 5 to 20 M ohm on C/H insulation test on valve tester.
Decided to power the heaters from a bench ps and try C/H leakage with a 500V
Megger insulation tester.
Increasing the heater volts from normal 6V , for short durations then back
to 6 , and monitoring on the Megger. Eventually taking up to 15V for 1
second , no longer orange glow of course, and vey low C/H Megger resistance.
Now measuring them for the C/H leakage on the valve tester better than 30
meg (maximum measurable on my tester).

Making a cheap and cheerful (but low resolution) microfiche printer.
Start with a thermal paper fax machine where the telecoms side has failed 
but copier function is OK. Or one of the many Ricoh FAX07 type with blown 
ps requiring just a 24V supply from somewhere, no supply to the lamp 
is required. Remove the active opto 
CCD section and extend external to the m/c. Make up some sort of sliding fiche carrier 
( i used an old 5 1/4 inch floppy radial slide )
with the CCD held underneath. Only a low power torch bulb above the fiche 
and a lens under and between the fiche and the CCD,employ in a darkened room. 
Remove the paper drive 
mechanism from the fax or couple across to the carrier by cogs and pulleys 
and bands for the right traverse rate

Storing rubber drive bands.
I doubt it will reduce the likelihood of any band 
'perishing' going liquid and gooey and disintegrating.
Sprinkle talcum powder over all of them - if one should go 
gooey then hopefully the liquid black colour will show 
up against the now light grey colour of the dusted bands. 
It may also reduce the transferred mess onto any adjascent bands 
should one perish. Methylated spirits on cotton wool will remove 
the goo well enough if repeated after cleaning off you fingers the first time.

Reducing chance of problems using an ammeter setting of a DVM / DMM
For those DVMs where you must swap the red lead to a different socket 
to do amp measurements and the plugs are elbow shaped. Stick a fluourescent 
contrasting coloured label under the red plug. Then when returning to 
use the meter and forgetting to swap the leads back there's a bit more 
chance of noticing before shorting the next piece of live kit thinking you 
are doing a volts test.

Crude basic test for checking MOS Fets.
The following is for n type mosfets and results do vary so it is probably best 
to try on known good matching FET before falsely discarding a suspect 
one of same type number.
Starting by identifying G,D,S if unknown and assuming starting in 
non-conducting state. Using a DVM on "diode" check with red and black probes. 
One pair of terminals only one way round should show a forward voltage x . The black is 
on the drain (D) the red is on the source (S) leaving the third as the gate. 
Put red to G and black to D then swap probes to D-S . There should be 
conductance less than x slowly increasing back to x in the limit.
Putting black on the G and red to D then should return D-S to full x value.
Or setting the D-S "voltage" to the low setting and just touching the G 
may reset to the higher "voltage" state. 

Wax covered capacitors from the 1950s
Proudly stating "British Made"
Yellow tubular wax covered caps, Dubilier type 460, TCC
type 343, 645 etc 300V to 750V caps in range 1 to 1uF going leaky ? 
On DVM resistance scale in Meg ohms but on a Megger then as low as 50Kohm.
Probably all such caps need replacing with modern or 
for the purists modern ones disguised in the original wrappers.

Pinch wheel replacements
Find a small local industrial rubber supply company.
Ask about cordage of the relevant diameter.
Drill a hole down the centre of a cut piece of this cordage.
To centrally align the drill bit well enough for this purpose.
Find a washer of right hole diameter for the drill 
and outside diameter a bit smaller than the cordage.
Place in a padded out (to raise up) chuck , 
minus screw insert, from an old power drill 
and place under a pillar drill to form the hole.
Local rubber suppliers to me, Hampshire, England
Portmere
Martins
Comrie
Technix
Preferably go in when its quiet and stock up with a range of "O" rings and
they may give you a sample length of cordage, otherwise about 2GBP per
metre.


Activating gear trains in VCRs under repair
Disconnect the motor drive belt . Activate with a small tyred pulley on 
a small DC motor driven from a variable power supply and a reversing switch. 
Touch the pulley against any relevant pulley or cog to save wearing-out fingers 
doing the same job.

Avoiding forgetting the code number for car stereos.
Assuming you have a favourite PIN number and the security number for the 
stereo is code then add Pin + code and write this number on the unit 
along with instruction to subtract your PIN number (undisclosed) from this number before entering. 
Also excellent tip for people who forget their credit card PIN number 
write the fudged number actually on the card. With any luck if stolen the hole-
in-the-wall will grab the card because the miscreant will assume it is a valid 
number.

Replacing components in awkward places.
Especially replacing component legs through pcb holes where it is too time 
consuming to dissassemble whole kit and kaboodle. When access is not suitable 
for holding part in jaws of surgeons ratchet clamp. With hot melt glue ,
stick the component at the correct angle to an old ball-point pen etc. When 
placed and soldered-in melt the glue bond to remove the pen.

Herringbone pattern on TV display.
That is roughly parallel lines of wobbly interference that sweep across 
the screen. If there is a VCR connected then it is probably interference 
from a harmonic/subharmonic of the output UHF signal of the VCR and a 
harmonic/subharmonic of a broadcast signal. Also called Moiree fringing. 
With a small jeweller's screwdriver slightly adjust the output frequency by 
turning the preset on the modulator 
near the VCR output socket. Retune the TV into the new VCR output 
frequency. I know an electronic engineer who with his family had been 
watching ,for some time,such a TV/VCR set up before I visited one time.

Removing jammed car stereos fixed in the dashboard recess.
That is the type removed with 4 steel prongs pushed in around the unit releasing 
the spring loaded retaining clips. Someone crudely removing these is likely 
to get one of the pins on the inside edge of one of these clips and so jams it 
outwards. Its a matter of using a separate steel pin and file-handle to push 
the clip inwards.

To repair cracked boards with .05 inch spaced tracks.
Reinforce the components side of the board over crack with hot-melt 
string (see gluing plastic).Clear away any loose ends of track at the break.
Away from the crack on every other track scrape-back varnish for a couple of mm.
Repeat further along the tracks on intervening tracks (gives space to solder 
without disturbing adjascent joins).Smear flux on these areas and pre-tin.
Prepare ends of varnished copper wire by scraping on 2 sides at the ends with a 
razor blade and tin with solder and recut back to leave 
just 2mm of exposed solder.Under magnifying lamp or equivalent solder 
into place.Near these joins place dabs of hot melt string to reinforce but allow 
for continuity testing and checks for shorts.Bond the loops of copper wire 
with odd bits of hot-melt to anchor to board.

Variant of the above for cracks in flexible .5mm spacing ribbon cable.
That is the type with a brown (phenolic?) semi-rigid covering used to connect 
flip-up LCD displays to the main board.
The thin (more coppery) covering first cracks then the copper conductor fails.
Bridge the actual breaks and one either side as a precaution with about .08 
inch diameter copper wire, anything much thicker will fracture on repeated bending.
Before doing any solder reinforce the bend covering with a melted 
film of hot melt glue so it can easily be remelted to bury the copper wires 
in after soldering as above and reinforces the good part at the bend. 
Also where possible turn the cable round end for end so a 
different part is stressed and reinforce area of bending with 
upholstery cloth tape.

"Making" a replacement .5mm or .05 inch pitch ribbon cable.
Find a scrap flipchip surface mount IC with the same lead pitch. Mask off the pins 
near the IC and at the ends and epoxy a line of bonding top and bottom. When cured 
cut away from the IC encapsulation with a diamond edged grind wheel. 2 of these are 
required. Glue one to each end of some cloth / upholstery tape gummed face up and 
temporarily fixed to  a base plate. Prepare some lengths of thin varnished copper wire 
pretinned at the ends. Skein in long loops and cut across with a razor blade then 
scrape the ends on both sides over a flat surface to remove varnish. Staggered 
solder to the "connectors" with the wires under a bit of tension fix to the tape 
  gum spaced at about the right pitch . Fix a cover length 
of tape over the wires and bond ends in hot melt glue. Plastic strip will probably 
be needed to pad out the contacts in the pcb connector housing.
If this doesn't work then bond the tape-ribbon direct to the pcb bypassing 
the original pcb connector.

How to read unreadable IC/transistor lettering
Yes, just like magic.
I could not read 3 of the 5 characters on a heat damaged TOP66 power
transistor.
I wondered if a sort of "brass rubbing" would work.
I just happened to have some plumber's PTFE tape to hand ( nominal 0.05 to
0.08 mm thick).
Laid a piece over the power tranny,  rubbed with a finger nail, and the missing characters
came up like magic.
As the characters remained on the PTFE, as an image , I realised you could
use this technique to read IC lettering where it is impossible to read,
because of constrictions and inability to introduce an inspection mirror or even just
where you cannot get the illumination at just the right angle to read.
You need access space enough to introduce a piece of PTFE and then rub it
with the wooden end of a small artist's brush, or similar, wrapped in some
of the PTFE, so it rubs easily without dragging.
Don't rub too firmly because you want the relief print to show as clear and
the rest of the PTFE becoming translucent rather than the original white.
Remove and read with a backlight or against something matt black. Maybe a
couple of attempts to get a clear image in all parts of the label.
May even be worth trying on reverse-engineering-proofed, rubbed off, IC
lettering. Useful for indistinct moulding logos / 
lettering etc on small plastic parts, gives some contrast.
Confirmed - this time a SIL IC with 
the lettering side of the IC 2 mm from a large block cap. Would have 
required 3 hours taking boards apart and back together to desolder just 
to read.
Used a 1mm steel rod covered with some PTFE tape for the "rubbing" and pulling 
a length of PTFE tight around the IC through the gap, 
and held tight while rubbing. I urge everyone to give it 
a try, so it is impressed on memory for when required in earnest, its just like magic

Mullard valve datecodes
A lot of useful stuff on the net but I'm still a bit stumped.
3 etched characters over 3 characters so later than 1956
characters are
mC.
B7A
The dot is splodgy so could be the lower part of something else.
Its an ECC83 so agrees with "mC"
the rest is Blackburn factory and January but was it 1957 or 1967 ?
I've never noticed before but comparing with a modern Russian one of 9mm
axial length of the anodes between the mica discs then this Mullard 
one is 17mm. Envelope dimensions are the same.
If a long anode (17mm) probably 1957, if short anode (14mm) tube 
then more likely 1967 for ECC82 and ECC83 anyway.

Buckled large electrolytic cans
Where one has been knocked but otherwise working order
Dent "pulling" with a couple of Jubilee clips does work to a large extent
but not total and you need to wrap a piece of thin sleel plate around 
leather before winding up. Both leaving a gap to see the dent. The steel to cover the area
where the clip ring enters into the clasp and contracts on tightening or the
aluminium can will be deformed inwards at that point as the leather will not
slip over the can.

Dealing with partially cracked fine pitch ribbon cables.
That is where they are used to connect a main board to an LCD screen via a hinge section.
Repair the cable as described above but turn the cable around end to end. Often these 
cables have bends and twists in them to give a tidy appearance. This of course is 
no longer the case when turned around . Adding new static kinks in this cable is ok, it 
is flexing points that is the trouble. If there is space in the hinge area or 
space can be made reinforce the new flexing part of the ribbon with adhesive tape.

Decoding Siemens capacitor codes
of type
B..... - $****
where . and * represent digits and $ a letter
Of the 4 digits after $ letter, the middle 2 represent the 2 leading digits of the 
capacitance value and the fourth the indicial multiplier in pF ('8' -> 10^8 pF).
B4... means electrolytic and B3.... means other eg ceramic,polypropylene, polystyrene

Hint relating to long lazy thread screws.
That is the screws with wood screw form used to close the casing 
of electric drills etc. These sometimes bind because of the length 
of thread and ease of driving slightly off axis. A dab of silicon 
grease on the tip of the screw avoids binding and the chance of 
fracturing the screw / head stripping on removal again.

Using motor brush / armature seating stone.
For fractional horsepower motors cut the stone to small size with 
an old hacksaw and glue to a small length of plastic rod or matchstick 
to get access to small apertures around enclosed armatures.

Captive nuts on the sly
With top cover removed introduce bolts through the fixing holes and 
tighten standard nuts on the inside. Cut some cable sleeving and 
slide over the protruding screw threads. Dribble hot melt glue 
around the nuts and allow to cool. Remove the screws and replace 
cover and screws.

Undoing security screws.
IBM torx with centre pin etc.With grind wheel in 
a dremmel grind 2 flats on the head.Then undo with parallel 
jaw pliers or open spanner.If stubborn, hammer an old screwdriver 
blade between the metal sheets being fastened with the screws.
Hammer small diameter steel stem of a pop rivet into 
the geap between pip and torx recess, if the pin bends rather 
than breaks then try bending back the other way with an 
old dart point.
If this fails then totally grind off the heads.
However undone , replace with normal headed screw.

Removing security version Torx screws with central pips.
Alternative cruder method.
Use a 1/4 inch square-section blank of lathe tool steel angled into the 
recess to shear off the pip. Protect other end with some 
copper or lead before hammering or use a soft headed hammer. 
Then use standard Torx bit

Possible replacement for rubber pulley tyres.
That is the perimetal tyres found on idler pulleys/ jockey wheel 
assemblies in VCR and tape decks.They are usually square in 
cross section but often an adequate replacement is ordinary 
neoprene rubber "O" rings from decent traditional hardware shops.
It may be necessary to put 2 or more side by side to fill 
the groove or 2 concentric rings to pad out the radius if the groove 
is deep enough to constrain the outer one in position.

Reconditioning old style phono sockets.
As used on old domestic amps using paxolin board like tag board with 
the same zinc? plated prass formed into split cylinders. Over time and use 
the cylinders open and break contact. Squash the cylinders a bit with pliers 
yes buit they will only open again. Tie-off some rubber cordage somewhere 
and loop a couple of times around each cylinder in turn, and vaguely tie off. 
In turn with pliers tighten each encirlement in turn and anchor end off properly.

Simple spectrum analyser.
Take a TV tuner and a very basic scope display. Make up a sawtooth
signal generator and feed the ramp voltage to the X i/p and the tuning
Vt of the tuner and feed the tuner if o/p , high f rectified , to the Y i/p.
For added
sophistication loosely couple the o/p of a TTL crystal oscillator to
the tuner for spot frequency harmonics calibration.
Possibly adapt for an RF strength meter by 
taking IF output, rectified to drive 
a 50uV analogue meter, but IF output 
may not be linearly related to RF level.

Fancy loudpeaker grille cloth
Sari shops were no help but found a good material shop, Fabric Land, don't
know if its part of a chain.
No knowledge of Tygan or Tigan but some useful names are
"Aida", white to cream , so need dying or painting, open weave hessian sort
of material.
Some coarse muslins similar but come in darker colours.
Most likely is something called "Black Tea Bag" , but rather stretchy so
would need to be sparayed with starch or dilute PVA, car paint 
works well.
My favourite was "Gothic Net", open weave black overlaid with tinselly
copper spider's webs but again would have to be stiffened.
All about 2.50 to 3.00 GBP per m run of 1.5m width or whatever such bolts
are. "pvc coated polyester mesh" is another fabric from sail loft/ yacht 
furnishings /tarpualin suppliers/ garden table cloth/grass-friendly camping ground sheet. 
Open weave "anti-slip" net is another possibility.

Freeing seized grub screws in knobs.
Before resorting to more brutal methods attach a rod to a vibrating 
engraving tool and vibrate the grub.

Replacing un-shrouded halogen bulbs
If they come in a blister pack , cut around the 
bubble with scissors and grip around the plastic and insert 
without touching the glass. Avoids hand/finger oil 
causing hotspots on the glass envelope.

Making a housing for rechargeable battery pack.
A non-technical customer of mine had the basic concept but needed 
help in making the housing. He had a minidisc player which 
used a small internal ni-cad pack costing £50. His mobile phone 
used the same voltage and a nicad pack of 3 times the capacity costing £25.
Could i make a housing for an extra £25 battery he could use via a lead plug 
into the minidisc and when required place in the charger.
His battery had 2 contact points at one end. Found a matching standard 
4 cell dry cell battery holder. Cut away all the internal moulding 
and all the metal contacts. Cut angled slots in one end so the 2 spring 
contacts could be "screwed" into the holes in the end engaging the battery pack contacts 
when inserted. Soldered a lead to these spring contacts. Surrounded that 
end cap with a wide cable tie cutting off most of the tail ;this is to 
locate the pack. Then melted hot-melt glue inside this cable tie 
and covering the springs.

Mica versus Silicone pad insulators
I was not convinced that for an existing used amp with 4x TOP66 power output
devices that the silicone pads were better than mica.
Each of the 4 white insulating pads had shrunk about 5mm at the tops (hottest)
compared to bottoms , ruffling the original outer edges, heat damage ?.
I'm wondering if they can chemically change over time and/or excessive
temperature , downgrading to be more of a thermal insuilator.
They are not discoloured or hardened or anything different in the
ex-compressed area by sight or flexing, just permanetly deformed , the
ruffling is permanent.
I replaced all 4 with mica and thin films of thermal grease.
Before doing so I powered up the amp with 400 Hz cointinuous sine giving 20
watts in a dummy load. No fan cooling for this amp, just
convection/radiation.
Laid a brass barrel protected thermometer on the heatsink and took
measurements. Stabilised at 33 deg C over ambient after 50 minutes.
Replaced with mica and redid the load test.
For same ambient , same testing position/attitude, power in load etc it now
took 30 minutes to stabilise at plus 32 deg C over ambient.
More graphically , but less scientific, - the finger test.
After half an hour of heating with the mica setup I could hold a fingertip
on each tranny for about 5 seconds before finding it uncomfortable.
Previously half a second of fingertip touch was enough.
I think I will rely on the evidence of my own observations and not
performance tables produced by the manufacturer's with an obvious vested
interest.
I've no reason to believe the original silpads had aged, been affected by
WD40 or anything.
I will assume they are , all manufacturers, all generically bad until a
similar personally conducted experiment, in a real situation, proves to me
to be otherwise.

When it is necessary to remove soldered in ribbon cables.
This is where there is just enough physical access to desolder 
the ribbon but trying to realign the cable to the holes and solder 
back again is a right pain.
Before replacing ,solder a SIL strip header to the end of the ribbon 
then solder this precise .1 inch pitch pins through the pcb.

Adapting motor pulleys.
When adjusting speed of replacement DC motors in cassette players it is 
sometimes necessry to increase the speed of rotation a bit 
to get within the capture range of the adjustment pot.A small length 
of heatshrink over the pulley will increase the speed.Fix a piece 
of wire to a soldering iron and while powering the motor shrink the 
tube to the pulley.Will work on the double pulleys of dual cassette 
decks as well.

Large rectangular buttons for push switches.
As found on mains push switches.
Rectangular polycarbonate and moulded mylar and 
polyester capacitors when drilled in from the leg side make colourful 
and convincing buttons.

Poor contacts on slide switches
Particularly the large multi-way switches used as function switches 
in boom boxes,tape play/record switches and radio waveband switches where 
a pin for pin replacement cannot be found.Try locating which contact is bad 
and then melt the solder at each pin in turn and push the pin with a small screwdriver 
putting a set on the internal contacts and hopefully picking-up a different 
section of the slide contact.If no good try again pushing in opposite sense

Inspecting contacts on slide switches (multiway)
Desolder the 4 or 6 or so solder points on the metal casing but not the solder 
points to the switch contacts.Although 
tongues of this casing are bent under the paxolin base of the switch it 
is weak metal.It is possible to lever off the cover ,unbending these tongues 
in the process.Beware of any return spring flying out and the little phosphor 
bronze contacts are very light and fragile.These contacts may vary in form 
ie 2x2 or 2x3 contacts so make note before removing. Bend back fully 
the tabs before replacing and bending under again or gluing if access 
is difficult.

In anticipation of Year 2000 problems in VCRs etc
Should there be problems using VCRs or other equipment 
with calendar /day of week programmed in.
Reset the clock / calender to 1994 for Jan1 2000 up to 
Feb 28,2000 then 1995 for Mar 1,2000 to the end of 2000 leaving only the 
leap year date of Feb 29 uncatered for.
This will give agreement between the date of the month 
and the day of the week in 2000.

Small thermometer for restricted space
Use a 1N4148 wired to a DVM in diode test.
Cross calibrate by fixing diode and normal thermometer 
to a slowly raised and lowered heated metal plate 
over a source of heat

A tip for current measurement with DMM 
Reducing the
chance of mistakingly using a meter set for current monitoring on live kit ,
thinking you are measuring voltage.
Assuming others here are like me, rarely use the current function of a
DVM/DMM.
Its not the blowing of a meter fuse that I'm concerned about. Its shorting
some expensive bit of otherwise working kit that I'm wary of.
I've not done it for a long time but there could so easily be some time in
the future, probably pushed for time, and there will be a big flash and a
bang.
A 5 minute job and peace of mind.
Fluke 77 with hot melt glue down the 2 current sockets and a dollop on the
rotating function switch surround. so it cannot be turned to A dc or ac.
A dollop of hotmelt in the "volts" socket of an old meter and a 2 croc-clip
ended leads, instead of probes, so very unlikely to absent-mindedly use use
that one in volts test mode.
Someone, like me, using the same DMM day
in day out, 99.99 percent of the time for other than current, may accidently
go to use this meter , still set in amps mode, for measuring volts , just
because it is so ingrained in using it for such purposes.

Repairing loudspeaker cones
Prepare some black cloth by melting and spreading some 
hot-melt glue string with an old soldering iron.
Also treat the periphery of any holes in the cone similarly and melt in a cloth 
patch.For partial breaks in the flexing 
part of the cone at the edge.Make up a series of rings of 
about 2mm wire so they sit inside one another and match 
the diameter of the outer part of the cone.Alternately lay these rings above 
and below some of the prepared cloth after remelting with low temperature  
hot-air gun and squash to give circular corrugations .This can then be 
remelted as a patch onto the speaker.
I have no idea whether this would be of any use in complete 
re-coning.

Coloured hot melt glue, especially for use with black plastic.
Cut the plain rod to make easier.
Hold with pliers , heat the outer surface 
with hot air gun and roll in coloured photocopier 
toner or dyestuff, repeat a few times ,before forcing 
through the glue gun to form hot melt string.
Not too consistent in colour so twist together and 
reintroduce through the gun for a second go.
Or wait until use, if as soldering string, then 
the toner will distribute much more evenly and blacker.
For small amounts of colour-matched coloured hotmelt mix artist's 
palette-wise on a piece of PTFE. Cut off a piece 
of white or coloured rod. Coat with some permanent 
felt tip pen , eg black for grey. Melt with an old 
soldering iron , leaving it flat on top. If colour not 
dense enough then recoat the flat sides and repeat. 
For gold, copper or silver use a "metallic" felttip marker for 
dyestuff. eg for silver unscrew the fine tip end of a 
"Pilot silver marker" shake with  a pad over the end 
to get a goodly amount of "silver" liquid.

Tip for people allergic to house dust / dust-mite detritis
It seems a bit pointless vacuuming with conventional vacuum cleaner and blowing 
the finest most irritant dust through the filter bag and back into the room.From a 
polythene products supplier obtain a long length of lay-flat polythene tubing that 
is made for polythene bag production (by heat-welding and guillotining).Fix one end 
of this tube to the exhaust of the vacuum and  lead 
it out into the garden through a window,then move from that 
end of the house to the other pulling the tube indoors as you go. Switch 
on the vacuum and all the fine dust-mite crap etc is then blown out of the house.
Try and avoid twists in the tube but angled corners are ok.One such tube inside another 
may be better for long term use with inevitable holes appearing in the polythene. 
It is possible to vacuum a house with hardly a sneeze which may be possible with 
expensive cyclone type cleaners but certainly not paper bag filter cleaners for those 
people susceptable to stirred-up dust.  
This same tubing can be used as part of a soldering fume extraction system or air inlet 
for a positive pressure full-face helmet but fire risks should be considered.

Opening "in line" or small switch mode power supply cases.
Where there is only one screw towards one end , often under the label, 
and the other end won't budge.
Try forcing outwards one edge near the corner, not on the end, with a small 
screw driver to free the nib from the recess which will 
break if forced off without this consideration.
Then slide off the end retainer and nib on the other side.
Then to reclose 2 small clothes peg wedges in place .
For very small boxes , ie in line headphone lead boxes, 
what looks like a decorative molding may be prizeable 
and hiding a fixing screw.

Thin sheet metal work
1	For normal drilling of thin metal you would back with a sheet of wood and drill 
after making a centre punch mark.For adaptation of existing equipment parts it is 
often not possible to back the metal so do the "drilling" operation with 
a small ball-mill mounted in a mini-drill.

2	To open out an existing hole use the "countersink" cutting edges of 
a centre drill as used in lathe-work to start a centred drilling operation.
Mount the centre-drill in a hand-held power drill to use.

Replacing the type of potentiometers with thumbwheels not shafts.
Often found in guitar effects units for compactness but off-the-shelf 
replacement is next to impossible.Use a shrouded preset of right value,the type 
with a central slot that can take a plastic spindle(engages with 2 sprung hooks) 
 that transforms it to 
something like a pot.Cut down to size this spindle and glue to plastic cog 
 from a scrap audio tape deck,drilled to accept this shaft.Use hot-melt 
string on both faces to securely fix.

Repairing thin-film-conductor ribbon cable
This is the ribbon cable with thin conductors of order of .2mm diameter copper wire 
flattened to .8mm wide,not the very thin chemically deposited ? conductor type.
For both the plastic shrouded and phenolic type char or at least affect the 
covering with an old soldering iron so it can be easily pared back with a scalpel,use 
locking flats either side 
of the ribbon on the good side of the break to act as a heatsink. For conductor 
spacing less than 2.5mm  staggered on alternate conductors make preliminary solder points 
with a low temperature iron and solder again with the heatsink flats clamped on good side 
of the break. Prepare some enamelled copper wire bridge pieces 
and solder in place.Reinforce with some hot-melt string.

General tip for spectacles wearers.
The following,surprisingly,i only discovered recently.It explains how it 
was possible for our ancestors to observe small objects when they had failing eyesight 
and before it was possible to make lenses. Should you be somewhere without 
 your glasses then make a pin-hole in a sheet of paper and hold centrally over 
an eye,alternatively bend your index finger around your thumb to make a small 
viewing hole.A decent 
light level is required,restricting the area of the eye's lens to the central (
least distorted) 
gives a clear image.It also explains why reading some script in low light is 
not possible but 
is readable in good light-the eye "stops-down".
Instead of cursing about specs sliding away when trying to view 
inside something while your head is near enough upside down.
Tie the ear-hook parts of the arms togethe rwith a few 
daisy chained and looped rubber bands. Place the band to 
back of head and move the lenses down into position to 
avoid knotting hair and bands.

Year 2000 bug fix
If like me none of the applications that you run on your computer need 
an accurate clock / calendar reset the system clock to say 1989 
instead of 1999.

To Remove gummed equipment labels
To remove gummed labels paper,plastic or aluminimum
from pieces of equipment use a hot-air gun/paint
stripper on low power setting.Warming the gum
makes removal as easy as original placement. 

Warning about soft plastics touching hard plastics
After pulling a piece of equipment out of storage for about 3 years i 
now know what causes the sometimes seen curvy marks etched into 
clear perspex-like cassette deck covers and similar. If the mains lead 
is wrapped around the equipment it can touch  the hard plastic.Over time 
the plasticiser from the soft plastic must leach out and soften the 
adjascent areas of the hard plastic. Same effect often seen with "rubber" 
grommets stored in the clear plastivc multidrawer cabinets and presumably 
the "rubber" feet of equipment if resting on hard plastic of other equipment.
Some related info
1/ see tips3 for the same effect inside a BSR vinyl record phono cartridge
2/ from Ron Jones
The problem occurs in all sorts of areas - leisure boats on UK canals are 
generally steel, and so have thick polystyrene insulation against the hull, 
then covered with wood panels. Boats of course vibrate - and cables getting 
brittle - even 12V ones are not a good idea.    All cables running in this space have to be 
run in a conduit, as it was found that the polystyrene would suck all the 
plasticizer out of the cable making it brittle and liable to break without 
warning.
3/ from Dr. Barry L. Ornitz
"Doll's Disease" is an entirely different phenomena 
than the leaching of plasticizer.  Doll's Disease is actually a result of 
cellulose acetate reacting with the moisture in air to produce degraded 
cellulose and acetic acid (the vinegar smell).  Originally it was seen in 
celluloid movie film, collar stays, etc.  Celluloid is cellulose nitrate 
with a little plasticizer but the plasticizer has nothing to do with the 
reaction.  With cellulose nitrate, nitric acid is produced.  Once the 
reaction occurs, the acid catalyzes further degradation of the cellulosic 
plastic.  Museum storage in sealed glass cases actually promotes the 
process.  About all that can be done is to neutralize the acid by washing 
in a dilute sodium carbonate or bicarbonate solution, drying carefully, and 
placing the item back in storage with flowing dry air.
The problem you are seeing is the leaching out of plasticizer from 
polyvinyl chloride or polyvinyl acetate items.  If you are old enough to 
remember vinyl automobile seats, you probably also remember the greasy film 
formed on the inside of windows when the car was parked in the hot sun. 
Over time, the vinyl would get brittle, shrink, and crack.  The film was 
plasticizer that evaporated from the vinyl.  As it left the PVC, the 
shrinkage. brittleness and cracking occurred.
One of the more common plasticizers was bis(2-ethylhexyl) phthalate, more 
commonly known as dioctyl phthalate or DOP.  It is still in wide use today, 
but many newer plasticizers are also available today such as 
trioctyltrimellitate (TOTM), dioctyladipate (DOA), diisononyl phthalate 
(DINP), di(2-ethyl hexyl) adipate (DEHA), acetyl triethyl citrate (ATEC), 
and even tricresyl phosphate (TCP).
Plasticizers are incorporated with PVC in the manufacturing process. 
Contrary to what Armor-All® and similar products might claim, you cannot 
put plasticizer back into the vinyl with a surface applied product.  Many 
products may contain significant amounts of plasticizers.  Very soft and 
rubbery PVC compounds may contain as much as 40 to 50% plasticizer. 
Preventing the leaching out or evaporation of plasticizers from vinyl 
products is prevented more by the choice of plasticizer than anything else, 
although low temperatures slow the rate significantly. 
About the only way to prevent plasticizer damage to other plastics is to 
keep vinyl products away from them.  Most coaxial cables for radio 
frequency use have a center conductor insulated with polyethylene, a wire 
braid shield, and a plasticized PVC jacket.  When the plasticizer leaches 
from the jacket into the polyethylene, its electrical losses increase 
greatly.  One modern innovation uses either aluminum foil or metalized 
polyester to wrap around the braid preventing the ingress of the 
plasticizer.  But it also provides better shielding allowing the braid 
coverage to be lessened from 90 to 95% coverage to less than 75% coverage 
leading to a much lower weight.

Replacing absent long equipment closure screws
Long (40mm or more) equipment screws with tapered lazy threads 
for fixing into plastic often seem to be absent from equipment (tinkerers).
Regular machine thread long screws are more readily available but will not 
bite into plastic.A not ideal solution is to twist 5 or so turns of a spring of 
correct handedness onto a machine screw ,heat up ,and push into the 
plastic,then remove leaving insert in the plastic.A stronger solution is 
to melt brass threaded inserts (as used in 2 part ABS boxes) to melt 
into the plastic reinforced with hot-melt glue and use standard matching 
machine screw.For seriously long fixing screws 
get some studding (plain threaded rod) cut to required length and on 
one end mount 2 nuts back to back and mutually tightened then 
with a hacksaw cut a slot in this "head".

To determine if an Infra Red light source is functioning
That is for IR LED o/p of TV remote controls,the end of tape light 
source on VCRs and the laser diode in CD players.For running off a 12 volt 
source an ordinary red LED ,an Infra-red 2 pin phototransistor and a dropper 
of about 1Kohm  (for 12V) all in series.For TV zappers will show visually 
variation of pulse train .Check on known good remote control,working 
VCR deck and working CD unit as spectral resposivity may be critical.It 
just happened that the phototransistor i used worked fine ,the response 
from CD lasers is less than other sources on my such tester.

Tip for not losing parts after disassembly
Often electronic repair consists of two parts ;disassembly and diagnosis ;
replacement and reassembly.Some days or weeks can pass between the two 
processes so place all screws and small parts in a labelled mini-grip 
polythene bag. If no longer than a day then use a plactic cutlery 
tray or similar with different compartments. If over days and many parts then a bag for each sub-assembly and 
before dismounting some parts mark with felt pen those that could 
have ambiguous orientation on reassembly particularly headers/sockets 
where the manufacturer has not deliberately used different number of way 
pins for unambiguous mating. Unfortunately I don't own one but 
a basic digital camera may be useful if they will work with a 
supplementary lens for close-up to record innards before 
disassembly. If just numerous screws of various types and sizes then mark on the chassis the 
number of screws of that type at each point of use, assuming they are different quantities.

To make a VCR mechanical functions test cassette.
For initially checking a totally unknown vcr to avoid a jammed 
tape and to diagnose visually and by feel tape transport problems.
Take an old cassette to pieces removing all parts retaining 
just the cassette housing and front flap.Prize off the 
clear panels in the top and cut into the central section to leave 
just a small central section(avoids centre activated trigger mechanisms 
catching in use) similarly on the base to avoid catching mechanical flaps 
that stop 2 cassettes being loaded into m/c.
Open up the holes in the base section leaving a bit of periphery 
for strength and the 2 recessed holes in the central section of the base.
Between the flap at the ends and the main housing 
stick some opaque tape to defeat the end of tape sensors.

Using a Q-Max cutter / Greenlee punch?
I had to use a 40mm hole cutter through steel sheet 
and had forgotten how to use them.
For the given size of allen key and the going gets too 
tough and you consider having to put a pipe 
extender on the allen key - no.
Once you have made the initial 2 diametrical 
cuts through with the allen key and it gets tough. 
Tap the profiled part of the cutter with 
some light hammer blows and take up the slack 
with the allen key.

If a replacement component is too big 
for the casing , cut a hole and fix in 
a sink strainer insert from a hardware 
store, perforations do not usually matter.

Audio cassette test tape
For anyone setting up the speed of a cassette tape unit and does not 
have an accurate signal generator and constant tone test tape to listen for 
beats.Make up a minute long test tape.At 1 7/8 inches per second for 
one minute translates to 9 foot 4 1/2 inches of tape plus 5 3/4 inches 
of leader at each end plus a bit at each end to fix into the reels.Do 
not use FF or REW as not as strong as the clear vinyl leaders.
Also of course this tape will not show up wow / flutter.

To fix aluminium chassis panels where the original self-tap 
screws have worn too large a hole
Cut the aluminium rivet part off a pop-rivet (blind 
tension-rivet) split along length with snips or similar 
and mount in hole ,check the screw makes purchase if 
not swage the rivet head to avoid rotation.

To remove brass pulley from the spindle of small motors.
That is where there is a interference fit ,warm the brass with 
a hot air gun on low setting initially and lever off 
the pulley.Use same technique to remove shafts from bearings and 
bearings from housings using a hammer with intervening block of wood or 
dowlling to minimise damage.To reassemble squirt aerosol freezer spray 
on the internal part and hot air heat the external part.

To remove stuck knobs on spline type shafts.
Wrap the knob with a strip of leather to minimise damage.
Use a pair of mole-grips (lock-jaw pliers)/ engineer's cramp 
or small vice to squash. initially light pressure, the 
knob diametrically perpendicular to the slot in the shaft 
which seems to be fairly standardised in sense relative 
to the zero position of poentiometers but preferably confirm 
before upping the pressure. 

To make a bezel suitable for surrounding a scope front 
where the original was missing.
Use 4 black nylon computer card slides that are found 
in 19 inch equipment sub-racks,cut each to length with 45 
degree cuts,glue corners with dabs of hot-melt.To 
give a more aesthetic finish in-lay some coloured 1mm bore 
silicone rubber sleeving into the channel that the 
pcb cards would normally slide along.This also 
hides any fixing screws .

Waterproof and structural bonding between metal and 
 metal or ABS.
This gives a waterproof and reasonably good bond that is 
breakable using heat if required.Hot melt glue melts typically 
at 120 degrees C,place the metal pieces (cleaned and roughened with sand paper 
in area to be bonded) in a low oven in 
excess of this temperatue,remove and with the hot melt gun 
run glue around the bonding area and allow all to cool.
Remelt just the surface to make the required bond with other 
prepared metal or ABS box. The bond to steel and aluminium 
with pre-heating has much improved shear strength.

Scratches on glass (monitor screens etc)
Beware deep scratches should be considered dangerous as the 
whole screen could crack and implode.
Clean out scratch with methylated spirits and allow to 
evaporate.Make up a paste consistency of water-glass 
(sodium silicate),traditionally used for preserving eggs and 
is the medium for making "crystal gardens".Allow to evaporate 
but not totally .Wash back surplus waterglass with a damp 
cloth in a polishing motion.
This technique can be used on car windscreens where the metal parts
 of broken wiper blades have made grooves in the glass.I had an old 
car that the windscreen broke on and could only find one replacement 
from a scrapped car but had these scratches.Went through the MOT 
after this technique and 3 succeeding ones;I thought the rain would have 
dissolved away the silicate .

Poor mans silver loaded paint.
Silver paint is better,lower resistance ,the following
gives a resistanc in low tens of ohms.
Required-graphite powder obtained from locksmith / 
keycutting shop etc and some spirit based
artist's fixative spray,from art supply shop,in the
UK used some Rowney Perfix spray (active solvents
Toluene and butyl acetate).Spray some of the fixative
into a small container and add graphite to make a paste
and apply to pcb surface or whatever.

Send/Receive 1/4 inch socket bypass switches
For those of you who say "always replace" - ignore the following. 
It is for people like me who find it pointless replacing with weaker modern 
replacements unless the original is obviously weak with much reduced switch 
closure force.
Yet another amp "failing" due to dirty/grimey such unused bypass switch.
I prefer to beef up the closure force on the existing ones , after cleaning 
the "contacts", (contact is too grandiose). The spring action is still 
good but beefing up will make dirtying/griming of contacts less 
problematic, loss of amp-preamp by-pass action less likely, better contact 
with 1/4 plugs where the send/returns are used.
Requirements - Hama beads (small coloured plastic rings, trade name, they 
get everywhere if kids use them) for making pseudo mosaics on a sort of 
pegboard found in toy / craft shops, the size required here 5mm wide, 
5mm outside diameter, 2mm inside diameter. 2mm silicon rubber cordage 
from angling shop.
Two plastic beads rest neatly in the exposed groove part of the flexing 
part of the switch, to spread load , locate neatly and act as grips during 
assembly. Take 2 beads and 150 mm of cordage , pass through both beads and 
return to pass through a second time. Pull the first cord to reduce the 
diameter, introduce the other cut end and by a "preristaltic" action pull 
the second run through each bead like this. Pull tight to form a loop of 
about 6mm diameter. 2 passes through 2 rings mean this loop stays as 
formed while finishing off. This loop, stretch over the open end of the 
socket, with the beads in the groove. Loop the free ends of the cord 
around the other side of the terminals and wires and tie tightly via the 
other side of the terminals at the "hinged" end. Swathe in hot-melt glue 
to avoid the knot untying and bond to the socket housing, to avoid the 
hinge end , free end of the socket , cordage dropping off again, unlikely 
as the contact ends drop in a slot in the housing . Cut off loose ends of 
cordage.



 Hint for small spot welding.
For small spot welds such as found on desolder irons between the barrel and flange
where they often fail due to being knocked.
Use a welding transformer of about 60 to 80 Amps.Connect one terminal to the flange
and the other to some wire of same composition to that being welded and about 2mm dianmeter
with end located over the intended join held in place with 
insulated clips etc.Place a small piece of tissue paper with flux paste on it between
this wire and the pieces to be joined.Switch on the transformer only long enough
to sputter a crude weld then switch off and break free the wire from the joint.
Repeat a number of positions around the join line,especially as this tecnique does
not work satisfactory every time.
Safety note: Keep the paper small as it will ignite in the process and sheild
your eyes from any UV from the arc.

Hint for making a coil winding m/c
The following will wind enamelled copper wire
less than .5mm diameter.
Main requirements a carpenters hand-brace drill
and a mechanical tape counter from an old tape recorder.
Mount all parts on a wooden base board.Fix a length of
threaded stud bar approx 3mm diameter in the drill chuck.
Fix the coil former with nuts and washers,centered to this
bar.Similarly attach a small pulley which via a thin rubber
(stretchy)drive belt connects to the pulley of the counter.
Feed a piece of thread around the "tens" drum of the counter
and around another pulley to form a loop.Join the ends of
this loop with a tension spring to keep the thread taught
and form the shuttle mechanism by feeding the winding
wire over any loop in this spring.For different wire 
diameters use different pulley ratios (also differing
count ratios).Determine the real revs to the counter
increment to give inferred number of turns.After putting
on one layer,stop winding,put a twist in the rubber drive
belt and continue till the counter returns to original
setting.Continue in this manner alternately twisting
and untwisting the rubber belt.For non-matching shuttle traverse rate just 
move the wire to other loops in the spring.For back-tension on the wire pass through a fold
of sponge lightly clamped.

Hint for gluing plastic, what I call hot melt string.
Preform some hot-melt glue sticks by melting into strings ideally 2 to 3
mm in diameter  using the hot-melt gun , extruding over a clean
metal sheet in a tight loop snaking pattern and allow to cool.
Using an ordinary (old) soldering iron melt the surface of the plastic pieces
to be joined and melt in the hot-melt string similar to soldering operation. 
If anyone has a use for 0.1 to 0.2mm hot-melt "candy floss" , with a 
hot dollop of melted glue on the end of the gun, attach to a cylindrical 
plastic container of some sort, rapidly pull away and wrap onto the 
cylinder.
For coloured hotmelt string (for matching) i found in a toy shop some watercolour paints 
in tubes as a liquid in range of colours made in China marked Grafix or Happy 
Hours. Mix colours and melt into the string about 1 colour to 10 glue and remelt in the area of repair.
The watercolour sputters a bit but mixes quite well with solder iron and matchstick.

Hint for repairing broken plastic cogs / worn cogs
For the situation where a section of teeth only on a
plastic cogwheel are worn or missing.
Wrap a piece of thin polythene sheet around a section
of the undamaged cog teeth.Wrap copper wire diametrically
around the cog pulling the wire into the root of each
tooth over an "arc" 2 teeth wider each side than the broken section.
Coat with epoxy to form a mould and allow to cure.
Undercut the edges around the broken section,demount the 
mould and reposition over the broken section.
Bind on and make good the cog with epoxy in 2 or 3 
stages.Finally fettle with a file.

 
Hint for dealing with pesky small circlips.
This is for E circlips,C circlips,push-on ring circlips and
plastic radial cut "circlips".
Prior to removing circlip push some fine (0.2mm or so)
copper wire between the circlip and the rod,tie half a
reef knot and anchor off the free end of the wire.
More importantly use this wire tether when replacing 
the circlip so it can spring off if it so wishes and be retained.
Pull the wire out when secured.
For plastic "circlips" pierce with a needle and pass
the wire through this secondary hole.

Hint for users of Weller "magnastat" irons
Before throwing away any worn tips with a couple of 
pairs of pliers pull the magnastat from the end.
Then in the future if you have a tip with the right 
profile and (say) an 8
(800 deg.F) end and you could do with a 6 (600 
deg. F) then replace with a lightly crimped on
No 6 with a lower Curie point formulation. 
If the copper shears instead of the magnastat 
coming off cleanly then drill out the remains.
If the bit does not easily come away from the housing 
due to corrosion etc. A pair of pliers on the bit and 
another pair at the other end of the shaft where 
the screw cover goes on but protect this thread with 
a strip of aluminium before gripping with pliers. 
Avoids  deforming the other end of the shaft and breaking the 
element. Remember the magnetic properties 
of this screw on cover seems to be included in the 
switch action. Don't condemn a switch or element 
before checking again with this cover over the 
shaft.
Converting a W2 (hollow thermocouple type Weller tip ? ) 
to magnastat W1 or P1 types. 
Or other types with small enough diameter to go 
in the heater and you can add a ring of metal of turns 
of wire or something to form the anchor ring.
Cut down the stem to about 20mm from the internal indexing 
edge of the ring. Saw 2 orthogonal cuts in the open 
end about 4mm. Bend the 4 flaps in and grind the 
tapers a  bit more to let the magnastat onto the taper. 
Mount through a hole in a vice and progressively squash together until 
17mm from inside of ring to switch engagement face of the magnastat.

Hint for making rubber drive belts.
The result may be a bit lumpy for accurate speed control situations {rumble}
and limited to larger spindles only.
Obtain some rubber cordage from a rubber supply company.I obtained 10m of
1.5mm diameter cord from a local supplier for 2.50UKP.  Practise the needle
piercing technique before going ahead proper which is:-
Cut off a length of cord to the required final circumference with a razor blade for good
flat faces.Find a small tube,say,20mm long that will slide over the cord{I used a
turret tag for 1.5mm).With a sewing needle pierce centrally on the end facedown about 5
mm,then remove the tube and pierce through the surface of the cord.Mark the exit point with a small
nick with the razor blade.Repeat on the other cut end.Feed button thread through the 
needle-eye.Push needle back through marked exit hole,through cut face,through
other cord end face and exit through surface.Pull thread through and tie simple
knot about 50mm from the rubber.Using latex gloves,mix up some epoxy glue and
smear thread to be pulled and the cut faces.Pull thread.Wrap the juncture with PTFE tape 
to allign faces,cure then tidy-up.For larger diameter cord pre-prepare the thread with
dots of glue to give better mechanical grip.For flat drive belts use 4 threads with
alternating "throws" across the cut faces.For 1.5mm diameter cord I obtained
1.5Kg tension over the joint before failure.If you have belts too long for the intended
purpose then reduce circumference with this technique.

Hint for heater element repairs
The thin stainless steel strip found spot
welded to multicell ni-cads make good crimps
for joining breaks in heater resistance wire.
Form a small length of this strip around a 
needle or something similar to make a tight
spiral with enough clearance to go over
doubled-up heater wire.Abraid or file the cut ends
of the broken wire.Crimp into place
with a double lever action crimper.
If there is an area of brittlised element around
the break then cut out and splice in a replacement section with
two such crimps.Such a repair to a hot-air
paint stripper (indispensible tool in any electronics repair 
toolkit)has survived at least 50 hours

Checking the play speed of a cassette recorder.
Requirements: a 1KHz test tape or a recording of an accurate 
1KHz tone made on a known good tape unit and played back on that machine 
to check, and an audio signal generator 
with a fully floating output ie no dc reference if not then de-couple the output 
with a couple of capacitors.Parallel together  one channel of the phones 
output of the tape and the output of the sig.gen. and a set of headphones 
in mono (L and R connected).With approximately equal sound levels 
you should get unmistakeable beat note .Reduce the beat to a minimum by 
changing the speed regulation of the cassette unit motor.
Is it possible with my technique to make a test tape using frequency counter
cross-checked sig gen and one good tape deck.
If the deck is actually out a bit it will still play back on itself at 
correct pitch.
So require 2 good decks and make a tape on each and try in the other ,
then unless both are out by the same amount and both up or down by that
amount then they should all be close to zero beats in all 4 permutations ?

To determine the voltges of multiple secondary transformers un-powered.
The following is a rough guide.
For an unknown transformer with an AC inductance meter measure
the inductance of the primary Ip and the inductances of
the n th secondary Isn .
X=square root of Isn
Y=square root of Ip
then with voltage on the primary of Vp then the secondary
voltages Vsn=Vp multiplied by X/Y
The power handling of each secondary is in proportion
to the ratios (Vsn x Vsn)/Rsn where Rsn is the dc resistance
of each secondary
Hence the current handling is power/Vsn

Forming brass eyelets without proper tool.
Required a multi punch leather punch and a 
few ball bearings.
Punch undersize holes in the leather, stout cloth 
, tarpaulin etc. With small ball located in a suitable 
hollow hole punch in the pliers , squash lightly.
Then repeat with a larger one, then with a 1/2 or 3/4 inch one 

Soldering connectors
For connectors with a plastic matrix 
holding the actual connector pins.
Mate the connector in question with a 
connector of the opposite gender then even
if you do melt the plastic it will re-solidify
in the correct registration.

Hint for repairing conductive pads on TV remote controls etc.
Preform some strings of hot-melt glue by extruding from
the heat-gun over a clean sheet of metal and allow
to cool.  This material in conjunction with an old
small soldering iron has many uses in the tool-kit.
But for this application melt evenly some of this
string over some black conductive foam-the stuff
for storing ics on (the soft kind not hard formulation).
Wrap some plumbers PTFE tape around a couple
of small metal plates and while the glue/foam is 
still hot,sandwich between the plates in a vice
and allow to cool.With a leather punch or thin walled
metal tubing of right diameter ground to a cutting
edge on one end,cut out little pads.
If the coductivity is not enough use aluminium foil.
Scrunch up and squash in a vice ,heat with a low hot air gun 
and melt hot-melt glue on one surface ,the crumpling aids
 the adhesion and punch out disks.
The next problem is how to glue to the rubber
of the remote control button moulded sheet.
I.m sure there must be more elegant ways
using cyanoacrylate glues etc but the following
is cheap and long term durable.
Find a small paper staple gun and staples,actuate the
stapler without any paper.Cut the resulting wire forms
in two and slightly open out to form wire V shapes.
Radially press at least 2 of these wire pins in the
stub of the contact button and any where else that
is relatively unflexed in use.With some of the
hot melt string and soldering iron envelop these
pins and the rubber stub in hot-melt and while
still hot press one of the conductive pads on top.

Hint for repairing holes in Jeans and trousers.
Well it is of more general use than the other esoteric stuff
on these pages.
Again using the good old hot melt glue .Clean and dry
the jeans,turn inside out,cut out a patch of denim from
some beyond-hope jeans about 12mm all round larger
than the hole to "mend".
Cut thin discs from the glue stick (gardening secateurs are useful for 
this (by-the-way secateurs useful for cutting thick or multistrand 
cables) and place around the hole
up to the edge of the patch then with a hot clothes pressing
iron and grease-proof paper or aluminium foil, iron the patch onto the jeans.
Use the paper/foil next to the iron to avoid glue seepage
on to the better-halve's clothes iron, or probably for family harmony 
use an old iron.
Putting the patch like this on the inside
avoids catching toes etc on the raggedy edge.
Washing at 40 degree centigrade is fine,60 degree or
above may be problematical.

Determining value of failed fuse with confusing or absent marking.
Use the mechanical cut-out function of an AVO 8 analogue
voltmeter.Set the Avo on what seems an appropriate current range
for the section of circuit being protected.Activate circuitry
and read current,if meter trips investigate further before
upping a range on the Avo.

Repairing vinyl record decks.
Before working on these remove the cartridge and stylus or protect well 
if not removable. Wire down the arm to the support pillar and remove the record 
platten if it is not positively held down.

Cheep and cheerful display bezels.
To mask cut edges of Ali box holes for display
bezels strip out the copper wire from some 
polythene insulated wire and split similar
to the above tip for rubber bands but
only make one extended cut.Instead of a
rectangular hole in the Ali make the ends
semicircles then only one end of
the sleeving needs to be joined.

Extracting screws well recessed in equipment cases.
Where stroking the shaft of a screwdriver on a magnet does
not produce enough transfered magnetism to
 overcome the resistance to extraction.The "proper"
techies self flaring 3 or 4 "fingered" grabs are too bulky
in the shaft to push into most case recesses.In cheapo
tool shops there are remote grabs about 2 foot long
with Borden tube shaft like throttle or bicycle brake cable and a T
trigger and spring at the end (6 in tool pics below) .Flatten out the fingers a bit for this purpose

Adapting a screw cutting tap for use in a restricted space.
Had to replace a tape head azimuth mounting screw because a 
twiddler had stripped the thread. Filed out the slot in the head to 
take a 2.5mm thread screw instead of the original 2mm. Problem was 
cutting a 2.5mm thread hole enlarged from the 2mm original. There was 
not enough space for the tap T bar or pin chuck recessed in the equipment. 
Find a piece of hex section aluminium or brass pcb spacer that will engage with 
a standard nut spinner. Drill out the hex to take the shaft of the tap . Drill and tap 
a radial hole in the hex to accept a grub screw to grip the shaft of the tap and then place in the 
nut spinner.

Replacing thermal fuses
It is usually advised to crimp thermal fuses into circuit but it is possible
to solder them (for space constraint resons) .Make a heatsink from thin-nose pliers with a stout
rubber band wrapped around the handles and grip the fuse terminal to be 
soldered and just prior to soldering blast the thermal fuse with a squirt
of freezer spray.

Checking solder integrity of Surface mounted ICs 
Make a small tool consisting of a stout sewing needle glued into the empty barrel 
of a ball point pen.By holding the barrel and rubbing the pin around all the IC pins a 
change of note will indicate suspect pins.Two of such tools are useful for 
prizing off the small plastic
 circlips used in tape /vcr units.Also useful for starting small nuts on 
difficultly placed small bolts,feed nut on one needle and hold back with 
the other needle-probe until the tip of the first is on the start end 
of the bolt.

Specialised variant of telepohone/modem/keyboard IDC connector
Need to reuse, after someone yanked the wires out, it is a non standard
form.
Going into a recessed socket in an epoxied box so no chance of wiring in .
Luckily clear plastic with this connector
Drilling 1.5mm holes opposite each of the prongy IDC bits, allows you to
push each one out cleanly with a jeweller's screwdriver.
Use a 1mm drill bit, by hand, to check the receiving channels 
are clear.

Colour code on radial inductors
If they are like this
2 large - Gold, Brown
2 small - brown,black placed in that order between gold and black it means
100uH, gold presumably means tolerance or just an identifier but its on the
left hand side of reading the dots, unlike resistor bands.
At least on pale blue cased globular ones it is
I chose a bad example
gold,orange,orange, black
means 33 uHenry
gold,brown,green,brown
means 150uH
For physically larger ones (again light blue body) with 3 dots only , read
from the top and multiplier nearest a pin. eg
brown,black,red = 1000 uH , not 200uH
For the 4 dot ones, the 2 small dots on the top, farthest from the pins, and
the large dots on the sides. So presumably a small 3 dot one, with one large
dot on its own, is the multiplier.

Checking Fax machines and answer machines.
As far as checking the response to an incoming phonecall.
If you have access to a BT line (in the UK) use the engineer's test dialing number.
It is not in my interest to divulge this number but keyphrases "BT line test facilities" 
and "ring back test" on the internet should be sufficient.

Checking fax machines (2)
Continuation of last tip. Requiring one known good m/c and the one 
under test. Connect both machines in parallel and connect to a BT line . 
Set one m/c to send a fax and one to receive. Use the ring-back test and when 
the receive fax engages disconnect the BT line. Swap over send and receive 
machines and redo the test.

Powering up old equipment.
Electrolytic capacitors in old or long unused equipment especially
valve (tube) era equipment can dry out and fail catastrophically 
when power is re-applied.To give a chance for old electrolytics
to reform themselves power up slowly using a Variac.This also
gives a chance of spotting overheating caps and switching off
before an eruption causes any mayhem.For anyone without
a variac for this purpose a mains bulb holder in series with
the equipment can be useful.Plug in an ascending (powerwise)
series of lamps eg 15W,40W,60W,100W,150W,250W.The bulbs
can also act as an ammeter,fluctuations showing that all
may not be well in the power supply.

Adapting 2 tools for restricted access use eg cassette deck mounting screws.
1) Flexible screwdriver, ie flexible shaft. I could not find a crosspoint/philips 
head flexible driver. Notched a hex driver bit by cutting a slot in the hex shaft. 
Opened out a bit and pushed on the original flat bit blade. Wraped the junction 
with some turns of brass shim tied with some wire,heated with a hot air stripper and soldered 
into a whole.
2) I found a useful miniature ratchet socket driver in a cheapo/shoddy tools shop. Handle about 
110mm long and hex shaft driver bits. Found some matching hex shaft pcb spacers to 
make extensions between bit and driver socket. To mate up, hacksaw the hex part off
a matching socket driver or nut driver .Wrap some wire round each part to 
loctate the bridge piece. Or drill out a 1/4 inch pot shaft extender as a bridging 
barrel.

Removing small plastic circlips
The circlips as found on the spindles of audio cassette decks etc.
Make two of the pin probes as described in a previous tip.
Hold the circlip in place with one of the probes and at the radial 
join in the circlip use the other probe to open up and remove most 
of the circlip.transfer this probe to the central hole of the circlip 
then it is safe to remove the first anchoring probe.

Misleading transistor and IC numbering.
All repair bods have to be told this one at some time.
On transistors marked C???? read 2SC????,similarly
A???? = 2SA????,B???? =2SB????,D???? read as 2SD????.
Also ICs marked A???? can mean LA???? (Sanyo) and
B???? can be LB????,C???? can be LC????. 
Also C???? and PC???? can mean uPC???? (NEC,for u
read mu) and D???? can mean uPD????.
On Sony ICs of the 70s and 80s marked with 3 digit numbers and no 
leading letter such as 174A and 174-2 read as CX174A and CX174-2
Motorola MC14??? usually you can drop the 1 and then read remainder as normal CMOS 
4000 series number.
Signal diodes with one wide band followed by 3 coloured bands , 
one convention, eg 
wide red , black, blue,red may mean the last 3 digits of the 
type is 062, in this particular case 1N3062
Sharp surface mount reulators , try adding PQ 
to the number on the body.
Thick TO126 transistor marked "H 669A" may be 180 volt 2SD669A with mounting face on 
reverse of normal , so reversed pinning, or mount legend face.
Harris powerfets , with just letter H...... read RFH......
Generally , but presumably manufacturer dependent
Transistor number with  an N suffix = lead free / RoHS pins/leads.
ie full tin coating, so scrape back for tin-pest free, long term
reliability, if soldering into old kit.

An Electronic repairman's toolkit
The following is a list of small handtools useful for the 
electronic repairman not including the obvious soldering-iron,wire-strippers,screwdrivers,etc.
Numbers in pics in () brackets in following text



2- countersinker, 3 - hole fettler, conical reamer ? a range of small size Torx 
drivers or Torx insert bits (not the Allen key type) are often tapered 
and make good PCB hole reamers due to the fluting



8,9 - parallel jaw pliers,10 3 prong sleeving pliers,  



(20,21) Frustrum shaped PTFE shrouds for SM desoldering and protecting other components ,
,(29) hole punch 

ITF means more expanded reference somewhere else in tips files.

1	Hot-air gun and IC extractor tool (ITF) (6) for removing ICs,freeing brass pulleys off 
small motors etc,instead of large soldering iron to desolder tinplate screening cans.
As an aside some more uses for the hot-air gun:- Starting barbecues instead of using surplus to 
Vietnam war processed napalm,repairing holes in old lead water pipe - use 2 hot air guns,one to 
dry out enclosed water and generally heat the pipe and the other one to locally heat to sweat 
in lead solder. Even a novice can do a functional repair like this as there is much less chance of 
the pipe totally melting away as with blow-lamp heating.  Also blowing over sheets of paper 
from copiers and laser printers where the toner has not properly fused into the paper. 
Mixing hotmelt glue with small rubber punchings from lorry inner tube to patch holes in shoes, 
after pre-heating the sole with a hot airgun.

2	Hot melt glue "string" (24,25) (ITF) and old soldering iron for plastic "welding"

3	Two needle-point probes (ITF) (28) for removing plastic circlips ,making good the holes in 
PCBs after IC extraction,prizing wire bound through and soldered on turret tags and chassis mount 
pot tags,introducing nuts to screws in awkward areas etc. Also modified dart body 
for heavier use (26).

4	Smallest of pocket torches and small bits of mirror,plasticine / blue-tack to stick 
on end of old telescopic antenna for viewing in awkward spots;also some 
mylar film (silvered plastic)-break open a mylar capacitor ,to read IC numbers etc when there 
is not even access enough to slide a piece of mirror in the gap.

5	Leather punch with various interchangeable dies (5); my set was made by S Cassels and Sons 
1918 still with all original 7 cutters,and various larger punches with pad of lead for 
punching out felt slip clutch pads etc

6	Engineer's scraper (1) (about the size of a gouge chissel  but tapered the length of 
the shank to a point,used properly for hand-scraping the bed of worn lathes) useful for opening out 
holes in metalwork.

7	Some joggled screwdrivers flat and cross-point ;these are double blade-ended shafts 
with a right-angle joggle near each end for restricted access.
For removal of CD platter motors buy a set of jewellers screwdrivers 
and make a joggled version of each one. Heat the shaft with a blow lamp 
but protect the active end with some pliers then with another set of pliers/ 
mole-grips bend the shaft to about 50 degrees (22) as near to the active end as possible.
Also the hex-shaped inserts 
and a pair of mole-grips(vice-jaw locking pliers) for even more restricted access.Also the 
impact driver (4) (combined screwdriver and torsional sprung anvil that can be hammered) that 
goes with these inserts for seriously corroded screws prior to having to resort to drilling out.
For removing cassette decks without removing all innards other possibilities are 
flexible driver perhaps modified (19) (ITF) or small ratchet driver (23) (ITF).

8	Flexible remote pick-up grabber (ITF) (7)for initial placing of awkward screws and 
picking up dropped parts and extraction of recessed screws.

9	A few assorted medical artery forceps (16,17)  (Spencer Wells - TV medical dramas have their use)  or needle holders (forceps with ratchet racks to 
lock gripping faces together - try angling supply shops) also similar type much longer with more play and mating jagged teeth because of the length for gripping larger items - sorry have not found the mecical term   .
Also on a medical bent a dentist's sickle probe (27) or two (rod with a hook either end) for joggling 
drive belts around tape mechanisms etc to avoid taking completely apart or crochet hook.

10	Parallel action pliers for undoing nuts, squashing the 
rivet parts of potentiometer pin to track and general holding functions one I have 
has marked date of 1918 ,Bernards of Conneticut and a smaller set marked Maun Industries,England.

11	Automatic centre punch (18) for starting-off drilled holes 
to prevent "skating" of drill bit.

12	A child's plastic "toy" microscope (30) of x20 or x30 magnification. Just the 
barrel is useful for inspecting record stylii and with part of the objective end ground 
down at an angle back to (or even into ) the lens allows to get close enough for
video heads to inspect in situ when illuminated with a torch. To
inspect whether the gap is chipped and generally whether worn down too much.
View in a downwards sense wherever there is enough clearance.

13	A good strong magnet from a loudspeaker or video head motor to stroke over 
with screwdrivers to retain undone small screws (to avoid dropping into the m/c ) or aid re-assembly.

14	Double action (heavy duty) end snips (12) for cutting off 
the internal portion of pop-rivets (blind aluminium tension 
rivets)(UK manufacturer Footprint Tools) traditionally used to cut off surplus copper nails 
after clenching the roves in wooden boat construction / repair. Useful 
for rough "knurling" of steel shafts where a plastic cog 
or pulley is slipping rather than friction fit.

15	Double action (heavy duty) gilbows(beefed-up scissors) (11) for cutting 
tinplate.

16	High power blower for blowing out dirt from inside of old equipment.
In the UK Martindale is a good name to look for 1KW hand-held,due to the 
air cooling so low weight.

17	Illuminated magnifying lamp on an "angle-poise" support,preferably 
glass magnifier and fluourescent circular lamp. If the cheaper plastic type 
of lens then cut out a circle of 
glass and fix immediately under the lens- molten solder and flux sputters 
will blemish plastic lenses.

18	For audio work often the only test instrument you need is a crystal earpiece 
with an earth clip and a probe replacing the jack. Also use for determining I/P and O/P pins 
of Sanyo STK hybrids when feeding in a signal and other audio problem areas in audio kit.
There is just enough signal from vinyl deck magnetic pickups to 
check for output on both channels.

19	Various holding devices: Vice with removeable soft jaws,a couple of engineer's 
cramps (13,14) (2 solid steel bars interconnected with a pair of screws with T bar handles -one small 
one medium,a retort clamp from a chemistry lab the type with opposible 3 fingers like  
thumb and first two fingers ,with soft grips,good for irregular shapes

20	A piece of insulated plastic such as a ballpoint pen barrel. To poke about 
in live equipment amongst cables ,components etc to check for intermittent contacts and 
dry joints especially (the bane of repairmen) intermittent problems. Another piece of 
plastic rod fixed in the chuck of an engraving tool to seriously vibrate boards/components 
while monitoring outputs etc.

21	Dremmel or other high speed (but variable) small hand power drill and small ball mills on 
arbors and preferably thin diamond edged cutting wheel on arbor.

22	Vernier callipers/micrometer and screw pitch guage along with reference 
tables for matching thread forms and screw cutting taps .

23	Circlip pliers (for small clips) - (15) start with ( Moore & Wright say ) set of (old) engineer's 
dividers. Undo the cross tie studding and reinsert the other way about . Obtain some 5/32 inch BSW 
(that old) nuts or make for 2 pairs to go back to back lock-nut fashion either side 
of the sliding anchor. Fix a fair sized knob to the studding. Splay the main arms 
a bit to give some room for the 2 central nuts and grind back the points a 
bit and after heating give a slight set to the points. For internal circlips repeat but 
with the points set the opposite way.

24 Dremmel or other low power high speed small drill with ball mills 
and set of carbide/centride coated bits , especially small cone types

25 Digital camera to photograph pieces of complex mechanism 
before disassembling. Also where there is no schematic for some 
kit take photos of components and track side , may be useful in 
the future for removed  or burnt cmponent determination

RIP
Unfortunately to save others from trying to find the "Forum Stores" in Southampton 
it is no more. That is the electronic junk emporium that over the years moved 
from the tram shed and Nissen huts of Richard Taunton School to Bellemoor 
School to the defunct boiler room of Montefiore Hall, Wessex Lane and finally 
a shed tucked behind the chemistry section of the university.
The educational trust carries on but the stores offshoot is gone.

Some interesting shops for technical stuff

GWM Radio Ltd
40/42 Portland Road
Worthing
Sussex BN11 1QW
Tel:  01903-234897
Fax: 01903-239050

Techno Trade
167 West Street
Fareham
PO16 0EF
Hampshire
Tel: 01329 234199

Tools,Hardware and Ironmongery Shops: 

Barron Tools,
332 Shirley Rd, Southampton

http://www.in-excessdirect.co.uk/
West End etc
end of line tools , fittings etc
Name of shop not noted but a "pound shop" type 
in the road where Winchester main post office was, 
excellent for the full range of Rolson tools etc

Stainless Steel fixings etc , specialist shop 
A2A4 Chhurch Rd, Shirley , Southampton
http://www.a2a4.co.uk/acatalog/
Useful for UNC , 
No longer off the street supply, you 
have to know precise details , from their stock, 
to pick-up the items there and then.
Otherwise mainly internet supply but no 
minimum order other than postage amount.
For anyone else often coming across American electronic kit 
The most common size is UNC 6-32, 8-32 and 10-32 are also common. 
That is AWG size 6, 8 and 10 all with 32 tpi threads.
Also 10-24 and 12-24 with 24 tpi are used. 

Ignore the name , ground floor of the 
interesting malthouse building has all sorts of stuff
Botley Bathroom Centre 
 01489-786272 
The Malthouse
Church Lane
Botley
Southampton
Hampshire
SO30-2EJ

Metal Supermarket, Mount Pleasant Ind Est, 
Southampton (national chain) , no 
specified minimum quantities, plenty of 
offcuts of non-ferous plates and 
profiles etc , sold by weight.
    
Street's,  11 East Street,  Havant
 023 9249 2460 , PO9 1AB 

Harwoods, St. James' Square, Yarmouth
Isle of Wight PO41 0NS
Tel: 01983 760258 



Diverse Devices,Southampton,England


Telephone number - the same number as it has been since 1988 
but email is now the preferred method of contact so number deliberately not placed here. 

I devote time each day to replying to emails.

   (obscure/obsolete components,second hand test equipment,
schematics etc)
Postal: 
66 Ivy Rd,
St Denys,
Southampton,
SO17 2JN
England   


e-mail 
diverse9@onetel.co.....m ( for anti-spamming reasons 
please remove all 5 dots ..... between co and m ) 
Plain text only (see below) 
 

 If this email address fails then replace onetel.com with fastmail.fm or 
replace onetel.com with divdev.fsnet.co.uk part of the address and 
remove the 9 . 
Please make emails plain text only , no more than 5KByte or 500 words. 
Anyone sending larger texts or attachments such as digital signatures, pictures etc will have 
them automatically deleted on the server. I will be totally unaware of this - sorry, again 
blame the spammers. If you suspect problems emailing me then please try using 
my fsnet.co.uk account. 

More hints & tips and repair briefs on
homepage http://home.graffiti.net/diverse:graffiti.net/