It may be time for a new UPS. My trusty APC XS 1300 has gone weird on me. I accidentally turned off the switch to the power supply. First thing that wasn't right, it didn't kick into backup power ...

APC makes it difficult to tell the difference ... I'm pretty sure that the XS (model with BX) doesn't do AVR Trim (only Boost) and doesn't have an external battery connector while the regular ...