u/Jer7440

I am working on a Yamaha CR 620. I have posted about it a couple of times. Someone else tried to work on it and they trashed a lot of traces on the right channel. They had components bent over to span gaps, and gobs of solder holding it all together . I decided I was spinning my wheels trying to diagnose the problem when there were so many questionable connections.

So, I decided to desolder some of what looked questionable and repair the board if I could. Can I get some feed back on what I'm doing? I'm slow as can be at doing this and if i'm not doing it right I'd like to know now!

The first pic is what I walked into, the second is after I desoldered some things and the third is a few repairs I've tried to make. Am I in the ballpark?

Can some one offer some advice on fixing my receiver (other than dump it)?

The right channel does not work properly. You can kind of hear it, but it is mostly static. Also if the right channel is active and I bring the volume up too high, the speaker protection relay will freak out.

I think I have tracked the issue to the power amp. The first picture is the schematic from the service manual. The signal (i'm using a 1000khz test tone from the signal generator in my cheapy meter) hits the power amp board at point RI(second pic). I have a normal sine wave at this point (third pic). Then, if I'm reading the schematic correctly, the signal path goes through c704 and r704. When I probe r704 with my oscope (pic 4) I get the funky reading in pic 5. Is it possible my problem is just with this cap, or can the bad juju be back feeding from the transistors farther down the line?

Also...someone else hacked on this before I got it (pic 6).

Am I chasing the right rabbit trail? Do I need to pull out everything in that section and try to redo it? Any advice would be much appreciated!