Art wrote:

Basically a DC to AC inverter with voltage and current protection circuits.
However there are also wave shaping circuits in the AC production section of
the device. In-depth troubleshooting and diagnostics may result in
determining what device is causing the fault however getting appropriate
replacement components may be the challenge. BE advised, the circuitry
produces voltages that may be considered lethal when in operation. Follow
all the safety rules endemic to this kind of service. IMHO: APC makes some
rather nice products, almost all are not consumer serviceable.

Thanks. We are fine with electonics generally, just never dealt with a
UPS before.

Thanks for the reply.