This was originally posted on APC forums on 7/4/2015
I've got an Smart-UPS 1500 that has worked fine for several years, until now. I went on vacation and it was working fine, when I came back my server room smelled like acid, the batteries were hot and the UPS was beeping that the batteries are dead. I disconnected everything immediately... I went out and bought new batteries and tried to connect it back up. When I connect the batteries I get an short and sparks fly. If I measure the black and red wires with my multimeter set on beep, it does not beep.
What's wrong? Why has it shorted out and is there any way to fix it? Pictures can be added on the circuit board etc if it helps...