This stereo amplifier from Sony flagship series ES is missing sound from Right channel. I serviced this unit 9 years ago of broken solders.
It's sensitive to knocks (yes, in amplifiers, some controlled "mistreatment" is required to diagnose), so first I suspect of more broken solders or bad speaker relay contacts. But as I touch near input selector (that row of 5 green bricks), the problem goes away. After switching input a few times, problem seems gone.
It's not wise to think that's all. Since it's a big motor-driven input selector, I decide to take it apart and clean it inside. See pictures of disassembly. Remember to mark everything with permanent marker, even if you think that it cannot be assembled back unambiguously. Sometimes you'll be wrong and serious doubts will arise when reassembling. In this case, inner shaft allows two possible orientations of rotary contact brushes, beware. Contacts were really dirty. I clean them with alcohol and rubber eraser. In more difficult cases I use fiberglass brush, gently.
Another cosmetic defect is that Source Direct LED doesn't stay lit when this switch is on. This LED is switched by [S208] via plastic stick [65]. This stick has a piece of foam that touches the switch, and this foam has disintegrated. I've replaced with a piece of 4.5mm thick foam, keeping the plastic sheet that it had on top (so the switch pin can't perforate foam).
No more problems with this repair.
It's sensitive to knocks (yes, in amplifiers, some controlled "mistreatment" is required to diagnose), so first I suspect of more broken solders or bad speaker relay contacts. But as I touch near input selector (that row of 5 green bricks), the problem goes away. After switching input a few times, problem seems gone.
It's not wise to think that's all. Since it's a big motor-driven input selector, I decide to take it apart and clean it inside. See pictures of disassembly. Remember to mark everything with permanent marker, even if you think that it cannot be assembled back unambiguously. Sometimes you'll be wrong and serious doubts will arise when reassembling. In this case, inner shaft allows two possible orientations of rotary contact brushes, beware. Contacts were really dirty. I clean them with alcohol and rubber eraser. In more difficult cases I use fiberglass brush, gently.
Another cosmetic defect is that Source Direct LED doesn't stay lit when this switch is on. This LED is switched by [S208] via plastic stick [65]. This stick has a piece of foam that touches the switch, and this foam has disintegrated. I've replaced with a piece of 4.5mm thick foam, keeping the plastic sheet that it had on top (so the switch pin can't perforate foam).
No more problems with this repair.
Attached Files
So let’s take...