Denon PMA-100M problem, service manual request

[rayma]

That's what conformal coatings were invented for.

 

[thimios]

Look for a leakage capacitor on the component side.
Clean input selector and any other switch.

 

[Endreigabi]

What do you recommend to clean it with? I haven't done this before. In the end, IPA is for sure.

 

[thimios]

You need to desolder & disassemble the input selector for better results but is a pain...
Try with a contact cleaner first.
Again,look for a leakage capacitor!

 

[anatech]

Where is the corrosion located? What part of the circuit? The switch may not be involved.

Toothbrush, alcohol. IPA would be best, but honestly it doesn't matter on the PCB itself. Distilled water would work for final rinse.

 

[Endreigabi]

Around R353. Left amplifier stage.

 

[Endreigabi]

Sorry for poor photo.

 

[anatech]

Leakage there would certainly be noisy. That may well be your problem. Wouldn't be the first time.

I thought the top side looked like it may have had a spill at some point. Not as bad as others I have seen. Brush off the top and have a good look at it.