I would really make sure that the heads, guides, capstan, pinch roller and tape tension sensors are all clean! Old tapes can shed and leave behind a surprising amount of gook in a very short time.
In auto-reversing decks you can have a problem where the machine plays fine in one direction but not the other, due to problems with the capstans and pinch rollers. Usually you can see this by observing the behavior of the tape itself as it passes over the heads in either direction- it should look exactly the same!
In auto-reversing decks you can have a problem where the machine plays fine in one direction but not the other, due to problems with the capstans and pinch rollers. Usually you can see this by observing the behavior of the tape itself as it passes over the heads in either direction- it should look exactly the same!