PPI ProMOS 50 repair help

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I have a PPI ProMOS 50 in need of repair. I will be looking it over and will report back what I find.

I am a new member and wanted to get this thread started and will keep this repair to this thread. Thank you for any help in advance.

There has been some previous rework on it and I suspect it has a different transformer in it. I believe it has a 2150m/am transformer in it now. If anyone has a board photo I can compare I would appreciate it greatly.

Jason
 
I have the FETs out off the board. I am worried about powering it to test as I see pin 2 on the opto has been hot, also the temp sensor has melted. The trace from the ground plane to the chassis has blown as well.

There is no obvious damage in the output side but every output trans on both channels is shorted B-E. Should I pull all 16 complementary outputs? There are 4 additional transistors on the output side, are they pre-regs for the linear +-15v regulators?

Please help, I have done alot of the homework and just need a helping hand if you would.

Jason
 
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This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.