My used YAMAHA CLP-635 works fine, but my wife is getting annoyed when she plays with the headphones on.
The problem occurs only with headphones on and is independent of the headphones and which port is used.
The problem is: While playing or listening to demos the level of the right channel gets lower until it’s completely gone and I feel like deaf on the right ear. Some seconds later it works again for some time. While the sound is gone it doesn’t help to wiggle the phones plug, or the volume fader. Maybe it helps to unplug and plug in the plug again, but it also can be a timing issue.
Had same/similar a few years back - after long troubleshooting, because fault comes and goes, it came down to relay RY1 on the AJK board (see yellow in picture). That is easy to replace - very common part to be found in any electronics store.
As a matter of fact - you can proof the point - remove the relay and add two little wires (red lines in the picture) to hard wire the signal path - if the fault permanently disappears it was/is the relay, if not … have to look further back in the path.
First I had to find out that I have to remove only the three screws at the top of the backside and slide off the top of the synth.
Then I measured which contacts are normally closed and which are closed when the clavinova is turned on with or without headphones (which is actually the same). I don’t know when the relay is not powered aside from the synth powered of.
One fact I noticed: the continuity beeper was beeping shortly on both poles which should be open while powered. This was not the case with the left channel.
So I followed your instructions, removed the relay and bridged the contracts and it worked!
Now I actually didn’t order a new relay yet and opened the relay to have a look inside and switched it manually a few times. I don’t know what was causing the issue, but now with the opened relay (covered it again) the problem is gone for now.
