PMH 1000 Fuse blowing - Bang

[valvewhiz]

Hi,

I have a friend's PMH1000 that I borrowed for the second time this week, worked o.k. for two sessions then when plugged in it went with a loud bang blowing the amp fuse, the plug fuse and taking out the breaker at the venue.

On opening the amp up and doing some resistance checks on the input and outputs of the PSU I can find no shorts, and also none on the power amp + and - rails.

Any ideas anyone, (I normally repair Valve guitar amps!!)

Valvewhiz

 

[valvewhiz]

Hi,

Further to my previous post, both switching mosfets have blown, taking at least one 0.47 ohm resistor out, what else is likely to have gone besides the mosfets?

I'm more at home with valves and hate switching power supplies

Thank you

Valvewhiz