I you all. I am having an odd problem with my Teac 4010 sl. It does everything great but will not play in the opposite direction. From right to left. Everything is clean and lubed. Can't figure it out. Plays from left to right and records. Fast forward both directions work fine too. When I remove the reels and disable the auto shut off the capstan and pinch roller and reel motors all work. But with tape on it it just stops and does nothing. Anyone have any ideas.
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First suspect is capstan motor reversing relay K3 having a dirty, corroded or burnt contact for reverse direction. Next most likely suspect (and maybe this should be the first suspect at this machines age) is a shorted spark quencher capacitor across the reversing relay contacts.
When a spark quencher (also called an arc snubber or spark arrestor) goes bad and shorts it conducts across the very contacts it was meant to protect from arcing. That often happens in the direction and speed that gets the most use (forward direction, 7 1/2 ips speed). Therefore, IF the spark quencher for the forward direction is shorted the capstan motor will run in the forward direction (although there will be no arc protection for the relay contacts) however when you switch to reverse direction the shorted spark quencher will keep the forward windings in play as the reversing relay energizes the reverse windings. The capstan motor will stall out because it is trying to go in two directions at once. Same thing goes for the speed, a bad spark quencher in the high speed mode can cause the low speed mode to malfunction because the motor will be trying to run at two speeds at the same time
Could be a few other things too but those are the first two places I'd look. The relay and its spark quencher caps should be mounted on the relay board. Look for bulging, cracked or burned spark quencher housings (the little oval things) although I've seen them malfunction with no signs of being bad too.
When a spark quencher (also called an arc snubber or spark arrestor) goes bad and shorts it conducts across the very contacts it was meant to protect from arcing. That often happens in the direction and speed that gets the most use (forward direction, 7 1/2 ips speed). Therefore, IF the spark quencher for the forward direction is shorted the capstan motor will run in the forward direction (although there will be no arc protection for the relay contacts) however when you switch to reverse direction the shorted spark quencher will keep the forward windings in play as the reversing relay energizes the reverse windings. The capstan motor will stall out because it is trying to go in two directions at once. Same thing goes for the speed, a bad spark quencher in the high speed mode can cause the low speed mode to malfunction because the motor will be trying to run at two speeds at the same time
Could be a few other things too but those are the first two places I'd look. The relay and its spark quencher caps should be mounted on the relay board. Look for bulging, cracked or burned spark quencher housings (the little oval things) although I've seen them malfunction with no signs of being bad too.