Hi John,had some fun with my Disc Drives that have stood,I first tried a cleaner disc,low priced from any computer store,try that first.If that does not help the problem come back to me. In between time I will check up on the self test mode for the Kn6500 to see if the problem in electronic,I had that with my KN7000 and found the drive had died but I found a replacement for under 15 GBP.
Regards John.D