I just blew up a FSP250-50LC PSU while trying to diagnose the problem of low voltage outputs on all rails!
Lessons learnt from the encounter :
- Use a power plug with earth. I have used an adaptor without a earth connection for the kettle power cord.
- Disconnect the charging cord for the scopemeter when measuring variables on the live PSU.
- Determine the polarity of the test points before using your probes. I poked my ground probe over the positive of the 180uF 450V capacitor. I have discharged 322VDC through the scopemeter to earth.
- Do not handle both probes with your hands at any one time. Fix the earth probe first!
My encounter destroyed the PSU with burnt components, explosions and smoke. Both the circuit breaker and the ELCB was tripped.