I recoated the contacts on this prophet 600 with the material shown in the image below. This stuff works great on all rubber contacts in keyboards... I have never had a problem with using it and never had a problem with it wearing off over time (although I have only used it for a few years). For contacts that are hard to find, such as the ones in this prophet, it is a great way to restore the functionality of all keys without spending too much money on tracking down parts.
One interesting note about the Prophet 600: it uses the same keybed as the Korg Poly 6. Yes, part for part it is the same keybed.
|CircuitWorks keybad repair (bought from BD electronics)|
In addition to the contacts, I recapped the power supply, replaced some pots, and replaced the battery. As far as the knobs (red!) I found these nice replacements from allelectronics.com . THe original unit was missing all its knobs, and it just didn't seem cost effective to track down 25 prophet replacement knobs.
These knobs are actually for 1/4" round shaft (the prophet uses 1/4" flatted shaft),but they have a set screw in each of them and can be attached easily and securely. The knobs also work with the 1/4" shafts modern cousin, the 6mm shaft, which is almost the same size but not quite.
Since the replacement pots I put on this unit had a 6mm shaft, the knobs were great in that they could be attached to both size shafts.
|This is what a repaired contact looks like.|