Casio WK-3200 keys stay pressed (not physical)

[Talboren]

Hello,

 

I recently picked up a WK3200 and am having problems with 8 keys in a row.

 

When pressed the key sounds at full volume and then cannot be played again (until switched off/on), the digital display shows the keys are still pressed.

 

I've tried cleaning the working side of the PCB with isopropyl and changing the order of the rubber strips to eliminate a physical problem.

 

I've found so far that only the top rubber dimple needs to be pressed for the key to sound (rather than both together for the working keys) which leads me to think that the bottom buttons are thought to be permanently pressed.

 

If anyone has had a similar issue or knows what might be wrong any help would be appreciated.

 

Thanks,

 

Nathan