I have a Yamaha P-45 keyboard. 6 keys stopped working (c2 to F2). I cleaned the rubber strip and it didn’t fix the issue. I then replaced the rubber strip and it didn’t repair the issue. Finally I replaced the contact board and it didn’t fix the issue. My question is: What else could it be? am I able to repair this? THanks!
That is not possible as keys are scanned in groups of 6 - It either has to be keys in groups of 6 starting at C#x or Gx if the select line is bad or alternatively it’ll be every 6th key of the select set if the respective scan line is at fault - therefore in your scenario … how about C#2 … F#2 ?
I think you could be right, C#2 to F#2. In this scenario, is this fixable? wouldn’t the scan line be in the contact board? if the contact board was replaced, then this would mean the scan line is also new right? thanks!
Yes and No - the replacement middle key contact board you replaced does get those lines and would have fixed it providing the fault was on that board. However, the select and scan lines come from the main DM board via that white flat cable that goes from the middle board to the DM board. Inspect that cable, make sure it is seated correctly, the blue stiffener is still in place (glued opposite of the contacts) and most importantly none of the contacts have been damaged, bent or curled.
If all that is OK you will need a meter to measure all the voltages on each pin of the connector on the middle board (easiest to access) to determine if any of the signals is floating. It’ll be easier to do with an oscilloscope because there are continually digital signals on the pins but can do with a DMM by comparing …