Maybe there is an issue with how the scope is set up?? The probe's slide switch should be on 10X and the Channel Menu for Probe should be 10X also.? Maybe the trigger level is set too low or the horizontal sweep rate is too fast.? When you press and hold the key for a few seconds, do you see the voltage stay at the level show on your previous post?
Parts on the MAIN board are very sensitive to static discharge and can be damaged by a zap (or by a probe tip shorting two leads together).? You should wear an ESD wrist band that is grounded through a 100K ohm resistor and work on an unfiinished wooden or carboard surface (a grounded conductive ESD mat is better) also.??
Steve, W3AHL
Steve W3AHL