Yamaha C-80: What Am I Walking Into?

[Soundscape]

So after 3 hours of servicing the front face I took another 11 hours replacing the 72 capacitors. Spent 4 hours just ordering the right caps. 2 hours re-flowing light solders. 2 hour glue service & parts repair/replacement.
That's what your walking into...per thread title. Just cliff notes from my C-80 as a redneck hobbyist.

 

[avantbored]

OK. I would start looking at the Left channel of the NEW CONTINUOUS LOUDNESS and the 6dB FLAT AMP. Prime suspects - opamp in the loudness control IC309A (NJM4558S) or TR301 (2SK389) dual JFET input differential in the flat amp. Going to need to scope out the input and output audio signal of those two components.

I brought this over yesterday and this comment was photographed and included with the new service sheet. We will see!

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So after 3 hours of servicing the front face I took another 11 hours replacing the 72 capacitors. Spent 4 hours just ordering the right caps. 2 hours re-flowing light solders. 2 hour glue service & parts repair/replacement.
That's what your walking into...per thread title. Just cliff notes from my C-80 as a redneck hobbyist.

The front panel buttons did seem to work better (less noise) after I brought it home. How'd you clean these?

 

[hopeless]

This is timely. Have a C80 inbound. Really like my C4.

 

[Soundscape]

I brought this over yesterday and this comment was photographed and included with the new service sheet. We will see!

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The front panel buttons did seem to work better (less noise) after I brought it home. How'd you clean these?

I started with deoxit5. Then used electrical parts cleaner. Did alot of button cycling, all buttons. Then used almost the whole can of deoxit5 soaking the tactiles, and pushing the switches over and over, then more deoxit5. And repeat. Until all the switches had a good "snap". I put cardboard down to soak up the excess. It took awhile. They were really dry.

 

[avantbored]

C-80 back home with me. An intermittent IC; I left the service notes in my car and can't be bothered to go down and confirm which one. But my tech just swapped them all out and now it's quiet as hell. Maybe they got in there and cleaned the switches too. Very quiet operation.

The inverted pre out connection is real. Bass response is unreal! Driving an M4 and sounding very very good.

 

[Semanon]

Gummed up input selector switches are a problem on these at this age point.
To your tech:
Those tactile input switches are a bitch to access. When in there, they need to be doused in a bath of cleaner multiple times and cycled alot, then lubed.

You got that right. But with patience and care they can be brought back to good and mine have not returned to badness in 3+ years.