Chosen Solution
Hi, I have a Yamaha psr-e223 and after removing the rubber contacts and cleaning/undusted the card, the B2 flat note keeps “ghostly” triggering itself, I turn it off and on but after a while it triggers itself again, first randomly beating but then soon gets stuck pressed on, disassemble everything again and double checked, but the note keeps triggering itself with not external/mechanical touch to the board. where is the problem? Can’t find any help on line about this.
Hi, How did you determine that it was the B2 note? Looking at the keyboard key wiring the B and F notes share the same wiring multiple path back to the CPU. Here’s an image taken from the service manual that shows what I mean. To prove if there was a problem with the B2 key you will need to unsolder the diode that connects the contact to the track multiple and check if the problem still occurs or not. (see purple cross between red and green arrow at B2 on image below)
(click on image to enlarge for better viewing)
