See post No. 18 Jan.Cut the cap.
Cap cut, and it's no longer tripping the RCD, but it's dead to the world.
I did suspect the cap was more a symptom than the problem, so it's going in the skip.
Will it matter what type/dielectric?That suggests it is a timing component rather than a snubber. It is good news that it has stopped tripping. Fit a new capacitor and it may spring into life. Be aware of Voltage rating, try to find 400V if you can.
I have two UPSs with the same fault. Haven't looked at them yet, but my suspicions are firmly on those X-class caps to start with.here are generally one or two X class capacitors on the input for EMI suppression. They go bang once in a while.
I took the second one with the fault and powered it from a non-RCD-protected socket. It's been happily working away for the past several hours.I have two UPSs with the same fault. Haven't looked at them yet, but my suspicions are firmly on those X-class caps to start with.