Beringer PMH3000

[daveball]

Hi All I have a PMP 3000 where one channel drops out intermittently . with a scope on the speaker output of both channels the channel that drops out has a 500khz 25v pp sine wave on it
has anyone come across this fault. I assume its the class D switching signal getting through ? possible filter capacitor.Any help will be much appreciated

Dave

[daveball]

hi all update on fault I have changed C53,C54 & C73 on the output board this has reduced the 500khz sine wave to 10v pp so I assume some other cap's are also faulty ?

Dave

[Evildoer]

Hi Dave.

Yes, you are right, it is D-class amplifier. Schematics could be found over the internet, if you need i can send you one.
I have fixed one amplifier. And it was a big headache - easiest way to fix it is to desolder output mosfets (irf 250n and 9640 as i remember) and check everything on the board. If you have any doubts - replace component. I'm pretty sure that HCA9001 and ixdd404 drivers are working in your case. Be careful - board tracks will easily tear off if overheated. And double check internal layers (it is 4 layer pcb and some tracks are inside the board) - some of them are broken sometimes.

Good luck.

[daveball]

Hi Evildoer

I cured the fault by replacing the rest of the filter cap's c72, c71,c92 & c90 .Both channel are now the same and the amp now work OK. Thanks for the offer of a schematic.I have the preamp section
but not the power amp.

Dave