Greetings EEVBees:
--I have a Heathkit IM-1210 DMM. It is not anything special in terms of resolution, but the bright red LED display makes it a joy to read. I was cleaning it up and preparing to give it a fresh calibration so I can flog it on Fleabay, when I noticed it was functioning correctly, only occasionally, and was very sensitive to vibration. The display was lighting up, some of the time, and giving decent readings some of the time but mostly either no display or gibberish.
--At first I thought it must be the IC socket interface, so I removed all the ICs and cleaned them, and put a touch of DeOxit on them and reseated. No joy. I examined the soldering, no visible problem. I then proceeded to wiggle everything, only getting zapped a couple of times. Eureka! There are six test points where a red jumper wire can be pulled out of its socket. Please see the attached pictures. I deliberately left wire "C" out of its socket, so you could see it.
--Here is the weird part. I live in Florida, and I do not use air conditioning, so on some days there is a rather wide temperature swing. Wire C had managed to back itself out of the socket and came to rest just touching the socket, but not held by the socket, and the other five jumpers had done exactly the same thing, they had all backed out but remained just touching. So if you held your mouth right the durn thing would work just long enough to confuse you. Who wooda thunk it? Duh.
--I jammed them all home and Bobs your uncle. When I get er done, in the next hour or so. I will flog it, and soon I will have enough money in my PayPal account to pay for a slightly used Fluke 87V, which I will snipe for bottom dollar. I have been turning green watching DJ gloating with his paws all over his yellow beauty.
"I told you so, you damned fools."
Hugo Gernsback 1884 - 1967
Best Regards
Clear Ether