Hi,
I'm hoping I can get some ideas on what to check in this old (1978) soviet-era electronic calculator I got from a flea market, the Elektronika EPOS-73A.
Got it home and plugged it in. It worked just fine at first, I used it a few times for a few minutes each time, "kid with new toy" style.
Then I disassembled it to clean the plastic case and the keys. I couldn't separate the lower half of the case from the board because cables are tied to it, so during the cleanup one of the cables going from the power board to the main board detached,...