Yamaha CLP-120 Clicking sound


I have a Yamaha Clavinova CLP-120. When turned on the piano works as it should, but for the first half hour or so of playing it randomly makes a clicking sound. When the clicking happens the sound cuts out from the speakers, accompanied by a second click at which point the sound comes back. But the display and all lights remain the same as if nothing has changed. Sometimes the sound can be gone for as long as 5 maybe even 10 seconds, mostly though it clicks rapidly as in: off then almost instantly back on. Either way I removed the top and tried to get a better feel for what was happening. The click is coming from a little black square part labeled omorion. I am a car mechanic and it sure looks like a relay, but i don’t really know what it is exactly. Anyway the little black square in question is on a circuit board that has the RCA audio jacks on it, as well as 1/4 ouputs, and there is a heat sink on it as well. I am going to assume it is the amplifier board but again I have no idea what I am doing here which is why have joined this forum. Please give me guidance. I would love it if it were as simple as purchasing a new amplifier board and plugging it in. That would be assuming someone out there sells it at a reasonable price. But I’m already 99% sure that its either not available or astronomical in price. Either way any and all suggestions are appreciated.

There are 3 muting relays on that board.

From the clicking, I’d suspect that the voltage going to the relays is not high enough to hold the relay until the keyboard warms up. I would check for bad connections.

Taking a close look at my pictures I see a second white relay. I don’t see a 3rd but I am sure if I had the board in my hands I could find it. By bad connection do you mean ribbon cables, or cracked solder joints in the PCB? Which also begs the question is the issue on the amplifier board or from the power supply? I know you cant answer these questions, I need to get in there and poke around and see what I can see. But I am curious what you had in mind.

I have solder joints on the brain because in my search of a solution it seems like there are other folks who have these pianos chasing other issues caused by solder joints.

Yes, I was thinking of bad connections through the ribbon cables and cold solder joints - especially in connections that can be stressed.

From what I see on the schematics, the power supply board consists of a bridge rectifier and a couple of capacitors. Each circuit board has its own regulators that are fed by this voltage.

It’s possible that C5 on the power supply has gone bad. If it is slow to charge up, the +18v supply could be too low for the +12v regulators. This would allow AC ripple to be present.

A low AC from the main may also cause the voltage to be low. Check that you are configured for the correct line voltage for your area.