YAMAHA ARIUS YDP-142 piano repair

I wanted to play the piano, but after I powered it on and tried to play E, I couldn’t hear anything. I tried different notes and I could hear them, so all notes were working except E. No matter how hard I hit the E key, it didn’t play anything…

I tried “restarting” the piano, but it still didn’t work…

So I had to open it. I am sharing this because there was little to no information online. I am in no way qualified to do this, so if you want to do the same, do it at your own risk.

First, take out the screws that are securing the top cover.

After that, gently tap the top cover from the left and right corners.

The top cover should move and be free to take out. Push it toward yourself, then lift it and place it in a safe location.

This is how the piano looks without the cover. Nice, isn’t it?

Next step is to unscrew the screws in the bar on the keyboard.

Next, remove all the screws around the hammers. Use a big screwdriver and then remove the screws with tweezers. Try not to let them fall under the keyboard.

Then remove the screws from the bottom side of the piano, it’s the second row of screws.

After those steps, you can push the keyboard away from yourself. This will make the space needed to take out the keys that are above the PCB and the membranes.

If you wish to inspect the contacts, gently remove the membrane from the start.

If you wish to remove the whole keyboard, don’t forget to disconnect the keyboard cable.

After I removed the keycaps, I cleaned the PCB and inspected all the contacts. I still don’t know why it stopped working. After some time, the key started working again.

Update

The key is sometimes still not working. I have already taken the piano apart a few times to inspect and clean the PCB again. After some the key starts making sound again, it fixes itself?! I don’t know what is happening, but it’s driving me insane…

There is also a possibility to buy a new pcb section of the piano keys but the cost is not the best… I will see if I will have to go that route later…

Update 2: Final Fix

After some time, the key stopped working completely. It also no longer starts working like it previously did.

After some investigation, I found out how the note presses work. There are two contacts, and the membrane also has two conductive pads, one of which is shorter.

When a key is pressed, one contact is shorted faster than the other. Based on that time difference, the piano can detect the speed/strength of the note being pressed.

The left contact looked damaged and did not show any continuity when measured with a multimeter. The other connections were fine.

After removing some silkscreen and measuring the traces, I found out that the connection on the through-hole component was not connected to the rest of the circuit. After adding some more solder between the trace and the contact, the problem was fixed.