Advice for tape drive repair / maintenance

I've not (yet) aeen a video recorder where the rollers have turned to goo. Not saying it can't happen, though. The usueal reason for tape chewins is wear on the reel-drive idler which means the tape is not wound nack into the cassette on eject (And may not be properly taken up during play/record, so it gets tangled round bits of the machine). Or wear of the backtension band so that the tape loops on the feed side of the head during play/record and gets tangled. Or wear on the pinch roller so that the tape runs away from the correct path. Assuming the heads are still good, a set of rollers and tension band is not expensive. Setting up the back tension is 'fun', and you will need a service manual for the machine (but hey, do you really have a machine that you don't have the service manual for?). -tony