Audio scracthy in voices w/out sequencing

[SKATCAT]

Some of the voices (only checked in combi) have a low volume scratchy noise that seems key press derived and can only be heard when there is no sequencer playing (stand alone voice). I checked and cleaned the 1/4" output jacks, no affect. Is it possible that this noise is software derived, which I have never experienced before now?

Also, this keyboard has two boards in the EXB slots 1 and 2 but does not show in the startup menu, neither does the RAM in slots 1,2 and 3. I attempted a master reset by reloading the preload from the hard drive, no change. Is there any other form of MASTER RESET that would be used by service techs?

Another annoying item is the fact that I can not COPY or MOVE .PCG files on my computer (downloaded fine as a zip file from KORG). I tried to make a floppy copy of the preload software and I keep getting a message that the disc is not recognized and may need to be formatted.