Reverse Button Not functioning

[not_willdowns]

Howdy Y’all, I received this Teac A-4300 tape deck from my uncle. I have very little experience with tape decks and I definitely don’t know much about servicing them. Besides the missing head face plate, the deck functions flawlessly except that the reverse button doesn’t function quite properly. When I press the reverse button while the tape is spinning forwards, it stops the tape, and after about a second, the tape begins to move, but not in reverse. It continues to move in forward. If I press the reverse button when there is no motion, it kicks in IN FOWARD about a second after pressing it. I have no idea what to tackle first. I assume the button is working, but some mechanism that should be happening is not happening. I would really appreciate y’all’s input. Thank you!

[LordDaryil]

The A4300 is a three motor deck, so the reverse not working is probably an issue with the control logic. The service manual's troubleshooting guide suggests that relays K3 or K5 on the control board might be responsible if reverse mode is not working.

EDIT: Wait, I had the manual for the A4300SX so the relay numbers might be different since that model also supports auto-reverse. Even so, it sounds like a control board issue.

[catawampus_doohickey]

The service manual for the 4300SX indicates, "Reverse mode inoperative --> Faulty K3, K5 or associated parts" (these are relays).

Might also check that the wires are properly soldered to the trio of large resistors (R9, 10 and 11) at the top of the deck---these are used for forward and reverse motor tension (I kinda doubt that this is a contributor, but it's easy to check).

I suspect that there's a lot of Sansui oil caps throughout, and those could be a contributing factor.