The holes were not "plated through" The connecting tubes were literally tubes with a seam that did not have any mechanical bonding apart from solder.
The tracks & lands were loosely bonded to the board, so the poor bloke try
The holes were not "plated through" The connecting tubes were literally tubes with a seam that did not have any mechanical bonding apart from solder.
The tracks & lands were loosely bonded to the board, so the poor bloke trying to repair the dry joints would have an extremely fine margin of temperature/ time to work within.
Radiospares tinned copper wire and araldite was dashed useful when it came to repairing a GEC.
Mind you, for a really impossible repair, was there anything to beat the IF assembly in the Pye 723 chassis.
I have seen Park Drive packets wedgeing them to a working position after an hours work and a hundred or so grammes of solder failed.
Anyone remember the odd hairbrush wedged between tuning knob and cabinet to keep the VHF biscuit tuner on station?
HN
e:
ularly annoying
I dont remember any tubes, I thought it simply relied on the component wire for connection.
I've soldered to loose things a huge number of times, and those GEC boards, and assorted junk grade PCBs where the pads are detached. It doesnt stop it soldering. It does make it necessary to scrape all crap off before heating the joint.
I think the GEC soldering was just careless 3rd world style penny pinching. Once there was at least some connection, they moved on.
33rpm records were handy for fixing LOPTFsNT
particularly annoying
Discrete "tubes" connected the layers. They were not plated through and were useless.
GEC boards were unlike any other. Desolder a component and pull and the top print layer would detach. The "tube" ensured braid or solder suckers didn't work, so on replacement the new component would force off the lower layer of print.
Braid was the recommended approach for GEC boards, but as the "tube" , component and both print layers were rarely in good thermal [or electrical] contact, this wasn't always a success.
I went to GEC Kidsgrove when they produced the rubbish. Attempting to educate them as to their problems I pulled a board off the assembly line and turned it upside down in order to fully explain the repair procedures at the retail end. 'Twas a little embarassing when all the components dropped to the floor :-{
HN
It was from the line before the soldering was carried out. All the components dropped onto the floor :-(
Sorry about the posting screw up. Got a new version of Agent and it isn't configured yet
HN
particularly annoying
Please tell me more about that.
You could divide engineers into two types, the ones that smeared the biscuits and the contacts with silicone grease, and the ones that did not.
I did not.
Used to pop out the contact springs of Thorn tuners with a small screwdriver so they laid flat, polish them with Duraglit, Bend them up to retention them then pop them back with my forefinger carefully applying pressure to form just the right amount of curl. Then refit the biscuits after giving them the Duraglit treatment too.
I'm still using version 1.93 of Agent, and it seems to do all I ask of it :-)
Let me know if you have discovered how to display the "Outbox" with the most recent post at the top please.
Check my headers, I'm 7/100 of a version ahead of you.
This clock using neons as the counting elements is worth a look:
Wow, memories :) My folks had a TV - I'm almost certain it was a Panasonic - somewhere around 1980 which was exactly like that. I do remember it having issues in the channel changing toward the end of its life, too. I also remember taking it apart when I was somewhere around 8 years old and finding the neons (and it actually wouldn't surprise me if I don't still have them in a junk box somewhere; I salvaged all the useful-looking stuff out of that set before it went off to the dump).
cheers
Jules
This is a bit of a sweeping statement which has gained "fad" status.
It would be worth breaking down the pros and cons:
1) Voltage driven mains detector requiring very little current to operate;. 1a) As such it is very sensitive and prone to showing false positives due to induced voltages or capacitive coupling. 2) Most cheap implementations are based on a single resistor to limit the current and many devices are not sealed against water ingress which may bridge the resistor leading to dangerous currents through the operator as the current path to earth is usually completed through the operator via a metal cap. 3) Such devices are often accused of being liable to giving false negatives due to malfunction - but this is no more so than any other detector and any detector should be proved before and after each session on a known live source anyway.Notes:
1a) is no worse in practice than modern "volt sticks".2) There used to exist professional implemntations of neon detectors that often did not incorporate a screwdriver - they were dedicated to the function of detecting livevoltages, Versions working upto several kV exisited and were used by at least the London Electricity Board.
Conclusion:
Better devices do exist now: Volt sticks reduce the risks due to point 2 and a test lamp eliminates problems in 1a).
However, if it is all you have to hand, it is better to use it than use nothing and bearing points 1a and 3 in mind, they are reasonably reliable.
Might be better to say ?catastrophic failure?. I plugged one in without checking. It was in a large housing, so I assumed that there must be a resistor in there ? why waste all that space otherwise? There was loud bang and bits of the lamp shot across the room, telling me that it?s safest not to make such assumptions.
done, ta
NT
this is all addressed in the wiki article on them.
NT
rote:
ticularly annoying
ient light, they
Thorough carbon removal can make most arcing LOPTFs work again, but its never possible to get rid of every molecule, so what remains is less able to resist breakdown than it was originally. Epoxying slices of vinyl on lengthens the air breakdown paths like a traditional insulator, preventing a patch of carbon causing arcover.
NT
Ditto, but I used Fospro.
Duraglit wasn't in the RS product list :-(
HN
One little feature that was found with neon mains testers was a certain type using a spring between cap and resistor that was a little too large for the resistor. The result was that the spring travelled over the resistor contacted the neon bulb and the poor user then became the total series resistance.
Never experienced it myseld, but I saw it documented in Practical Television.
HN
They were not stabilisers in themselves. In the Bush they merely acted as a triggering device for the thyristor stabiliser. As the neon had a fixed striking voltage it was used at a time determined by the R/C network controling the HT.
I may be wrong on this, but apart from the tuning neons on some sets the only other neon was in the line timebase. This conducted in the case of excess HT and killed the oscillator thus preventing the set becoming a scource of X rays & fireworks.
A neon when conducting passes microamps, so I would imagine that it's uses as a stabiliser would be extremely limited.
I remember I had a japanese comms receiver with something similar. O/K for oscillators, but I would doubt if the current it could sink would suit much else.
There's being polite! What about the meal remains and other unmentionable organic debris that customers spread about with their fingers?
HN
When lashing up a circuit on the bench (teenager at the time), I moved something which shorted out the series resistor. Bang, and the remains of the glass were embedded in the wall.
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