Sony TPS-L2/WM-3 running backwards

Discussion in 'Tech talk' started by quaz30, Aug 21, 2020.

  1. quaz30

    quaz30 Active Member

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    I've wanted to talk about this for a long time. I've had 2 WM-3s and TPS-L2s on my hands so far and all but one of them had the issue of spinning backwards after replacing the belts.

    I hesitated to mention this, as it could just be a dumb mistake of threading the belts incorrectly, but after examining everything and getting the same problem on 3 different machines, with the belts installed absolutely correctly, I decided that it can't be the belts.

    The servo board on the WM-3 I'm currently working on outputs correct voltage, it is not reversed. So it must be the motor itself.
    Has anyone experienced the same thing? Reversing the leads to the motor fixes the problem and everything works fine. I can provide images of the belts if anyone doubts they are installed correctly.
     
  2. Boodokhan

    Boodokhan Well-Known Member

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    It should be the belt. I understand that you rechecked it but it cannot be anything else UNLESS:

    If the previous owner unsoldered the motor wires and soldered them back in reverse position !!!! (maybe the motor was dead and previous owner got a working motor and soldered the wires in a wrong way
     
  3. quaz30

    quaz30 Active Member

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    That's what I'm thinking, but the solder joints on all of my units looked factory...
    I also have a TCM-600 and I changed the belts in exactly the same fashion as in the WM-3s and TPS-L2s and it turned the right way.

    I've read a bit about magnets and *apparently* it's possible for a magnet to reverse its polarity in certain conditions. It could also theoretically happen due to changes within the magnetic material.

    I strongly think that is what is happening inside the motor, because I checked the voltages on both my TCM-600 and WM-3 and both are identical, with the same polarity going to the motor.
     
    Last edited: Aug 21, 2020
  4. Boodokhan

    Boodokhan Well-Known Member

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    belt orientation is similar in all TPS-L2 replicas (WM-3, WM-3ex, TCM-100 and TCM600).
    I have never heard about changing magnet polarity just by itself. Its interesting to find out how to fix this issue on your walkman. We never had this issue or at least as far as I remember none of the members dealt with this issue in the past.

    well,
    I think your best option here is to reverse the motor wires or place the belt in a wrong way! to get the right direction on tape movement (unprofessional advice :wink2)
     
    Last edited: Aug 24, 2020
  5. Silver965

    Silver965 Well-Known Member

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  6. quaz30

    quaz30 Active Member

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    I had no idea the belt was supposed to make a twist like that, I didn't even notice it even after looking at the photos for some time! Thanks for clarifying what was the issue.
     
  7. syndicalex

    syndicalex Member

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    It's funny, I did the exact same thing when I fixed my WM-3, I've uploaded a video where I explain the mistake ,I thought I was going mad!

     
  8. quaz30

    quaz30 Active Member

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    Yeah, you'd think a belt with a twist like that would be the incorrect way to route it, not vice versa. Bizarre, especially since other Sony mechanisms using a similar belt path don't have a twist like that: WM-2, M-301, for example..
     
  9. Silver965

    Silver965 Well-Known Member

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    Great I'm glad you solved it :thumbsup:
     
  10. syndicalex

    syndicalex Member

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    The thing I noticed is you can hear 3 clicks in close proximity for every rotation when it's running backwards, it's easier to notice this than anything visual while it's disassembled.
     
  11. Dejan Mosharevski

    Dejan Mosharevski New Member

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    I stripped open my wm-3 litterally less than an hour ago clean it because the play would not release fully and when i put it together it was running backwards and chewing the tape. I said to my self congradulations you made it worse, then after tinkering with it i swapped the belt around at the motor and it fixed it, thank god
     

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