I recently picked up this ancient APC Smart-UPS 600. It’s so old that it still carries the original APC logo. When I received it, I could hear something rattling around inside. After opening it up, I discovered that one of the relays had broken loose, likely either during shipping or while it was with the previous owner. The relay’s pins had completely snapped off.
Compared to newer UPS models, this older design has several areas that don’t seem to be as well reinforced against transformer-induced vibrations. As a result, components appear to be more susceptible to mechanical fatigue over time.
I decided to replace the two other relays as well while on it.
Afterwards I also repainted the inside of the bottom part of the chassis where the paint went off in an apparent battery spill that must have happened a decade earlier. I applied anti-rust primer and new black paint.
