I bought a early 1980's-era Hitachi VCR (billed as a VTR on its casing) and connections, dispays and buttons all work. Only thing not working is its heads (the most important part). Putting a tape in results in loud mechanical clanking sounds. The tape refuses to play, rewind, fast forward, or even rewind. The counter doesn't move, nor does the tape position. Does anyone have advice for repairing tape heads?