Probably bad or dirty heads. If accessable, clean the play/record head (big silver spinning drum type) with a light claening solution and cleaning PAPER not q-tips or any other lint/fiber producing swab as they may infect the head with such. Also clean the erase head (black one before the drum) and the audio head (silver head after the drum). Check the pinch roller (black rubber) and guides. Good luck.
Terry T. @tagproductions@sbcglobal.net, November 2005