Just closing the loop on this discussion! I obtained a keyboard assembly from Reverb.com, which included the KPC Circuit Board w/ EPROM 2.33 chip. I swapped the board this evening and the VFX works like a champ.
As you indicated @Vladistone, there were multiple areas of the VFX that needed attention and care. I removed ALL the keys, cleaned and wiped the keyboard coils with DeoxIt, created custom 20P ribbon cable (re-using the ferrite choke) and swapped out the KPC Board from an assembly I picked up on Reverb.com. Looking forward to having fun with both SD1 and VFX!