Sony TA-AV480 Channel fade fault tracing

[0x1A4]

Hey All,

I have this unit and it was working fine until it got warm, then I sat down to work on a set and noticed the right channel was weak. I tried balancing it with the balance circuit, got better for a second and then gradually faded away to now almost nothing at full right.

I plan on pulling it apart and checking the solder points, but I was wondering, are there any other fault tracing steps I could perform before I begin disassembly?

Also, I am new to stereo repair, I come from the cell-phone/computer repair field, and I do not have experience with capacitors this powerful. What is the s.o.p. for discharging these bad mofo's? Everything I have read as to what rating of resistor to use or for how long is highly contested and I would like it '...from the horses mouth', as it were. Being taken out by a sony would just be damn shameful...

Anyways, hope you all can help me out, but thanks either way guys. I am loving this site.

 

[rayma]

the right channel was weak. I tried balancing it with the balance circuit, got better for a second
and then gradually faded away to now almost nothing at full right.

First, get the manual and study the schematic. https://www.hifiengine.com/manual_library/sony/ta-av480.shtml

 

[sgrossklass]

Sounds like a contact issue. Find the speaker protection relay at the output and give that a tap in operation to see whether that changes anything. It's usually pretty much the same kind of effort regardless of whether you clean the old relay (contact cleaner on some blotting paper comes in handy, also something oily to seal the contacts - if you see burned spots it's probably too far gone) or replace it right away. You generally can't open these without unsoldering them first, though occasionally there may be a trick involving clever hooks or dental tools.