This mod has been well documented over the years over hundreds of threads on the VS forums. The problem is you have to read hundreds of threads, comments, mis-information, etc….
MPC-500 Tact Switches
Tact Switch Repair for the MPC500 MPC1000 and MPC2500 Fixing and replacing non-responsive tact switches can bring a dead worthless unit back to life. This does take a bit of…