Yamaha P105 Keyboard no sound. Bad Amp, DAC or Potentiometer?

Hey everyone,

I have a Yamaha P105 keyboard that I picked up for free. It's in great physical condition, but the sound is broken and I'm trying to understand why.

By broken I mean that there is no keyboard sound and the demo songs don't work. The only sound I can get out of it is what sounds like a bit crushed/distorted audio when I select one of the keyboard sounds or the demo songs. It plays for about a second then nothing. I know that the CPU works because the MIDI system works perfect, all of the keys work, the buttons work, the lights work and the debug options work.

This keyboard has 3 different audio outputs; the onboard speakers, the headphone out, and the line outs. I was expecting there to be some differences between them, but the same problem is present on all of the outputs, which is the lack of piano sound and only the strange distortion that plays when changing modes. Interestingly, changing the volume does produce a scratchy sound that is typical of potentiometer failure, but the distorted sound effect does indeed get louder as I increase the volume.

I don't have a schematic for this, and originally I was thinking that amplifier chip (YDA 175) was damaged, but since the problem is also present on the Line Outs, I am more inclined to think that the DAC (WM8524) is damaged somehow.

I suspected the amplifier because of this post I found, but the chip on my board has no signs of damage.

https://www.alexanderpeppe.com/yamaha-p1...

My board looks like this:

Amplifier chip is IC22 and the DAC is IC23. Has anyone seen anything like this before? Does a DAC chip fail like this? Could it be the amplifier, or the volume potentiometer? Any help at all would be appreciated!