PS4 DS4 controller (V2) button problem simultaneous pressing

Hi there,

I recently got a broken DS4 controller with multiple issues.

first the ones I got rid of:

  1. Right stick had a drift → replaced and fixed.
  2. corrosion on touch pad ribbon cable → bridged with jumper wire and fixed.

now the ones that I came across after the first two repairs:

  1. at first both rumble motors were working fine, after replacing the stick the right (light) motor doesn’t respond. the motor itself works, but there is no voltage on the pins on the board when enabling the rumble function. so the problem is somewhere on the board.

  2. after connecting the controller, everything else seems to work fine at first. then after playing a while, buttons “triangle” and “cross” are always responding together, when pressing either of them. the problem persists on any system (PS4, Windows, Nintendo Switch with adapter)

Does anyone have an idea which part of the board could be responsible for that? the button contacts are all good, I gave it all a good clean, so I suspect there is some faulty chip or other component on the board. I could not find a topic with a similar problem, so I’m asking here first.