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Tascam Porta One - Motor not spinning. Dead, or could it be something else?

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  • Tascam Porta One - Motor not spinning. Dead, or could it be something else?

    Hello!
    Sorry for what is probably a very basic question, but I'm just getting into analog electronic repairs.
    I've got a Tascam Porta One four track recorder. Just bought it. It looks PRISTINE. Everything seems to operate fine except one big thing. The motor doesn't start spinning when I hit any of the transport keys. So, until I get that working, it's just a very simple mixer...

    I have too many questions, but my main one is: how do I test if the motor is the problem. I mean, it clearly doesn't spin, but would there be some bit of signal between the transport and the motor that somehow isn't being transmitted?
    Additionally, I own a multimeter, but I don't even know how to go about testing if the thing is getting power.

    I may be hopelessly too new for this thing, but the intention here is that I learn how to fix this sort of thing, because it's really fun, so far, to mess with the more mechanical elements of these tape machines.

  • #2
    Open it up carefully, some of it is on the top and some in the bottom, with wires connecting the two. Look at the transport. The capstan is also the shaft of the flywheel. Note which way the capstan turns, or at least should turn. Now underheath, give teh flywheel a little shove in that direction.

    Many times a bit of dirt or even a hair gets in the gears and it stalls. Giving the flywheel a start often will make it finish the cycle it is stalled in.

    No help? OK see if you are getting 12v on the motor.
    Education is what you're left with after you have forgotten what you have learned.

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    • #3
      Thanks for the reply Enzo! Sadly, no, it needs a bit more than a nudge. The capstan motor wheel itself, the part that connects to the belt, never turns. Typically, it would turn as soon as you press play, or most other transport buttons. But this doesn't, even though it doesn't feel at all stuck. It moves very nicely with little effort, if I turn it by hand.

      I know that in some versions of this transport, the motor (and subsequently the capstan) always turns no matter what. Not the Porta One.

      So, yeah, I can't figure out how to test if I'm getting 12v on the motor. There's just the few little wires connected to a bit of PCB sticking out of the motor. Do I first de-solder those wires and check them? Can I check them while they are still soldered onto the board?

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      • #4
        Here's the motor control circuit. As Enzo said, check voltage at the motor. You don't need to unhook anything just yet. Of course the motor could be shorted and loading the supply, but I've not seen that in the Porta One. If there's no voltage at the motor, THEN you may want to unhook it and check the supply again.

        Click image for larger version

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        "Yeah, well, you know, that's just, like, your opinion, man."

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        • #5
          Originally posted by neckcarpenter View Post
          I know that in some versions of this transport, the motor (and subsequently the capstan) always turns no matter what. Not the Porta One.
          Just in case you don't know, there is a switch that detects a tape is installed. Without that switch being triggered, the motor will not turn.

          "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

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