Dead APC Back-UPS RS 1000

[berkutta]

Hi

Have here a USV which died through a dead computer PSU (short circuit). Now it only response with the "overload" sign on startup. I think there's something wrong with the mosfet stage or something like that due the short circuit. There are no burned parts or anything else obvious. A Battery Change doesn't changed anything on it. APC doesn't want to give out any repair manuals or schematics or anything else.

Are there here any persons who has knowledge on such things? What do you think about that? What would you do first on it?

Benjamin

[berkutta]

got it working again, dismounted the two mosfet stages on the top left and from 6 mosfets are 2 dead. Replaced them and it works fine again