Hi there. Occasional lurker, first time poster.
To start, I do have experience with electronics and repairs, but I wouldn't consider myself advanced. I know stuff, but some of what I come across here is totally lost on me. My day job is IT (mostly help desk) and my side hustle is repairing pinball machines.
Ok, so the reason I'm here... I recently purchased an APC Smart-UPS 1500, model SMT1500, on Facebook Marketplace. The seller said it worked fine but would probably need new batteries "soon," so I couldn't fully test it. Well, "soon" really might right away because they're dead, so I bought a set of aftermarket replacements. I installed them and, aside from appearing to charge curiously fast, everything seemed fine.
Alas, everything was not fine. Once the battery reached 100%, the unit threw an "output over volt" error and shut down. This happened no matter what I did or what settings I changed. Strangely, during one test I managed to measure approximately 123 or 125 volts (I can't recall which) in the few second window before it shut down... certainly didn't seem over voltage to me. I also found that it works perfectly fine with the batteries disconnected, but together the batteries measure around 27 volts.
Obviously the guy still says it worked fine for him and won't give me a refund... so I figure I have little to lose and take it apart. I found a section of
very charred components on the mainboard. One piece was so fried it just fell out and I have zero clue what it was.
Questions...
- Does this seem repairable or does the board look too far gone?
- If feasible, what components should I replace?
- Alternatively, does anyone have a clue whether I might be able to swap the entire board (640-3081A_REV06) for one from the rackmount version of this UPS (640-3081_REV03)? They look very similar aside from the battery connector.
I think that's all I have at the moment. Hopefully this thing isn't a lost cause.