LED watches - buyer beware!To anyone thinking of tracking one down, these are the main problems I've encountered with them.
1) Main enemy is leaking batteries. If these were left in the watch after they expired, it's probably been ruined by battery acid. I have succeeded in cleaning up one or two but it's very difficult and the watch is unlikely to ever work again.
2) Sticking command buttons. If there's been an attempt to free them using normal lubricating oil it will either have leaked inside the watch and killed it, or completely destroyed the rubber seal and jammed the buttons solid. The only lubricant I would dare to use is (expensive) "dry film" lubricant which doesn't contain oil.
3) If the watch has "stopped" and is continuously showing an unchanging set of LED segments, it could require a new quartz crystal. Sometimes these crystals become inefficient causing the circuit not to oscillate any more. They can be sourced and fitted but it's a tricky job requiring good soldering skills and eyesight.
There is also the hazard of missing, faulty, LED segments, although surprisingly I haven't found this to be a major problem.
I hope this helps anyone who sources an LED watch making an expensive mistake

Before I sign off, here's another couple of old goodies for your delectation

A very scrappy example I happen to have at work. Rockwell, a chip manufacturer, briefly got into manufacturing calculators in the early/mid 70s (using their own chips, naturally). The styling with the distinctive brown rounded keys is the standout feature. Note the "percent" feature. Features taken for granted now, like "memory", "percent" facility, and "constant" were all charged considerably extra for and emblazoned across the front!

A customer at my shop left me this knowing I collect old tat! The 0860 number is still written on a stickytaped bit of paper on the back. Sometimes I feel like walking down the street bellowing into it just for a laugh
