one of our new (only 4 year old) 1KVA APC UPS stop working and through error P13 contact customer support.
the equipment is out of warranty , upon investigation, we found the inverter board has the fault on the output hybrid relay circuit.
The inverter output relay is parallel by SCR/Triac to enhance the relay performance or other means.
We replaced the SCR with new device,, but the device is not power on as expected.

Further research on the issue found that, the error P13 (event ID 107) is latched on the UPS nvram/MCU and need to clear/reset using a service procedure....