Chattering Sony Tape Deck
 

I have this nice Sony TC-K670 deck I bought a couple of years ago for
recording from high-end sources, it's a great deck but it's had an annoying
problem almost as long as I've owned it. After it's been on for a few
minutes, something inside (probably one of the motors) starts to chatter
loudly. It's an irritating, high-pitched sound as if something is in need of
lubrication. It has no effect on the decks performance, it's just annoying
enough that I can't stay in the same room with the thing. I had a TC-WR570
before this and it had the exact same problem, so I guess it's quite common
on these. Is there an easy fix for this, or will I just have to be content
to keep my distance? These things are murder to take apart and reassemble
(three-motor PLL transport system) and I don't want to risk damaging
something.
Thanks.