Does the RK05 have a similar problem? I didn't know that, but I do have a couple of RK05 drives that I want to get working sometime. Unfortunately I have to fix both my RK8E and my RK11D first, though.
I have three DEC RA8x drives that have failed (all of them fault with "spin error") because of bad photo-interrupter tachometer sensors. After talking to a few friends, it sounds like this is a pretty common fault. Photo sensors like this are fairly common, even today, but the specific parts DEC...