UPS - Uninterruptible Power Supply.
I have a now non-working one, a NOVA 600 AVR.
It went well for about 3 years straight - never off. Now it's never on!!
Pulled it apart and found the battery had split along one edge. It has a tiny voltage now of 0.5 V.
It is a 12 V lead/?acid type.
Ran a multitester along it, carefully inspected it for blown fuses, got nothing, and found none. The two fuses were
intact. Of course, there's a heap of intervening electronics, but it all looks intact too.
Now the Q:
Does anyone know for sure how to test one? A new UPS costs about $130, while a new battery costs $35.