I have a D6C Walkman Pro -- bought in, I think, 1990 -- that still works (or did last I tried it, anyway, maybe a couple of years ago). Great little deck; with metal tape and Dolby C, did a fine job recording CDs.
I replaced the belts, which got playback working again (see picture here https://twitter.com/chris_cannam/status/1043961675114840070) but ffwd/rwd appeared to be victims of a seized pivot which I couldn't get moving. So it plays beautifully once more, but still can't wind.
Might be worth checking that yours is still going ok, in case lack of use is a factor.