PPI PC4100

[S Merlington]

This amp had blown power supply fets..

I replaced All gate resistors (47 ohm)

I replaced all Power supply fets (IRFZ44N)

I replaced Q76,Q79, Q53 Q57,Q68,Q78 which i belive are the drivers

Q82 thru Q86 get red hot as soon as i touch the remote to the amp..

I removed the BYW29's Still same issue Q82 thru Q86 (Fets) get red hot and the amp draws excessive current as soon as i tounch th remote wire to the amp..

The other side Q1 thru Q5 (fets) remain cold to the touch..

Anyone know what im missing here?

 

[RiLoWa]

When I have as much blown in the power supply of a PPI amp as you do, I replace the 3525 also.

 

[S Merlington]

Ok ill try that to see if that is it

 

[S Merlington]

Replaced the 3525 ..

Still same issue power supply fets on 1 side get red hot as soon as i touch the remote to the amp

 

[S Merlington]

Ok fixed that problem amp powers up and idle's perfectly..

Now the right rear channel is dead no output..


Do theese amps have muting transistors and if so does anyone know the board locations??

 

[1moreamp]

Q30,Q32,Q51,Q49 according to my info on hand these are all J108 mute fets, and they appear to be in parallel. with Q30 & Q32 on one channel, and Q49 & Q50 on the other... hope this helps some😉

 

[S Merlington]

All of the J108's test good

Amp still has no output from the right rear channel


Any ideas what to check next?

 

[1moreamp]

Have you checked the switches in the preamp section? Try and inject a signal at the large mylar caps on all channels to actually verify that all channels have output, then go back to the front end of the amp if all the main channels check out. Also measure the DC offset on all the channels, if your defective channel has DC offset I'm thinking its ok but your front end may not be passing a signal to it.. Just thinking off the top of my head and remembering what my 4100 looks like inside....😉