Thank you, Mooly. This is by far the most supportive community I ever encountered. Proud to be part of it.
I will surely try the aluminum foil trick, it sounds clever.
Agreed: I have to start from the strange voltage readings on the bad ch. I will check and compare with the working one. I will also print your schematics just to have an approx guideline at hand. I'm starting to think that the problem is not component related. Remember, somebody has put his hands on it before (found the signal wire soldered to the ground!). So it's an extremely hard task: no schematics, no clues about what's been done, very bad layout, very little experience of the repair person.
The problem with desoldering components on this damn piece of gear is they are hard to identify on the bottom side. Plus, there’s no room between them, so you have to flip the PCB back and forth dozen of times before to find out which is which. With transistors you have to desolder two terminals at least, and then bend them, but no room for that, sometimes no room for MM leads either. Never saw such a (horrible) layout.
All that said, I have to admit I’m quite tired with this unit. It's been incredibly frustrating and time consuming, months already before to join this forum, so I have to put this task on hold for some days. I have other repairs to do, not to mention my job.
So, thanks for now, I’ll be back soon with hopefully better news.
I will surely try the aluminum foil trick, it sounds clever.
Agreed: I have to start from the strange voltage readings on the bad ch. I will check and compare with the working one. I will also print your schematics just to have an approx guideline at hand. I'm starting to think that the problem is not component related. Remember, somebody has put his hands on it before (found the signal wire soldered to the ground!). So it's an extremely hard task: no schematics, no clues about what's been done, very bad layout, very little experience of the repair person.
The problem with desoldering components on this damn piece of gear is they are hard to identify on the bottom side. Plus, there’s no room between them, so you have to flip the PCB back and forth dozen of times before to find out which is which. With transistors you have to desolder two terminals at least, and then bend them, but no room for that, sometimes no room for MM leads either. Never saw such a (horrible) layout.
All that said, I have to admit I’m quite tired with this unit. It's been incredibly frustrating and time consuming, months already before to join this forum, so I have to put this task on hold for some days. I have other repairs to do, not to mention my job.
So, thanks for now, I’ll be back soon with hopefully better news.