Hello Everyone!
The past day in my thrifting adventures, I came across a Melcor 390 calculator, a nice specimen from the pocket calculator revolution of the 70's! At least, it's cool to me! Anyway, the unit worked a treat when I got it home - naturally the first thing I did was open it up and check out the board, the traces, the IC's, and all that jazz - but I noticed while it worked fine early on, once I closed it back up it started to just not power on. This got me worried so I opened it back up, checked around on the board and cleaned up a few old solder blobs that had dried up from manufacture (those probably caused no issues to begin with but you know how it is, ya see it, ya wanna clean it) and was for a few minutes confused as to what happened, thinking I had broken it.
That's when the magic smoke happened - a part had blown. Now, the unit is pretty darn simple - 9 volt battery, the wires for the power, the display LED's, and 2 boards - one for the keyboard, one for the logic - this had one little red object that I *think* is a ceramic capacitor on it (I could be totally wrong of course) and that part had very clearly blown. Considering the battery was getting oddly warm I should have known something was shorting out, but it didn't click - I was too concerned, almost childlike, with the fact I had a working device not 10 seconds before hand, and once I went to seal it up and power it back on it then didn't work right. I guess that part shorted internally and next thing you know.. pop!
I fear it may have damaged the IC's but at the same time, maybe not? I don't know, I'll trust what you guys think. I'm not new when it comes to electronics, but I have only a moderate knowledge and experience with many things beyond simple repairs, some understanding of the principles, and some skills with video game consoles (mostly mechanical issues though, so, eh). I still have enough compitence that, if we find out what the part that blew is and get a replacement I could get it in there without issue.
All I can do now is link you all to the images of the unit. If you need anything else, don't be afraid to ask - I don't mind taking more pictures or what have you.
I hope we can figure this out, but if something is probably beyond dead, then that's fine too. I just don't want to give up on this calculator, even if it was a cheap find - I'm sure some of you can relate.
Thanks!