I have a Sharp HK-9000 I have recently acquired with a few issues. Corroded battery connections and murky switches which I can probably try to venture in and sort out myself (I hope the switches just need contact cleaner and the corroded battery compartment will likely need some scrubbing and baking soda solution if that will even work) as well as a radio tuning dial which feels great but does nothing I'm not sure about.
However the main issue that I have no clue on is that one of the tape decks doesn't work. On the working deck, when I press play, the rollers start to move and a metal mechanism rises and locks into place for the head to read the tape. On the non working deck, which is also the recording deck, when I hit play the rollers (The ones that turn the reels) don't move and the head mechanism starts to rise but then just drops back down again and the play button unclicks, as though I had told it to stop or the tape had finished.
My terminology might be off, but I am happy to be corrected or explain better! I could also post a video of this as I can press play with the deck door open.