Walkman WM-7 Power Issue

Discussion in 'Tech talk' started by DerekE, Jun 15, 2020.

  1. DerekE

    DerekE New Member

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    Hi guys, new around here. I did that thing where you take a gamble on a non working unit hoping it’s an easy fix. I bought a WM-7 in lovely cosmetic condition that looks like it was cared for. I know it’s a complicated unit but I always wanted one as there are childhood memories attached. I have others which have been easy enough to clean, change belts and use. So I was hoping it might have been just a dodgy battery connection but no such luck. Voltage out and to adapter input is fine (also tested with my 3V adapter) but no lights or any sign of power. Is there a tut somewhere that can show me the best methodical way to trace along the power route to see where there might be an issue? I’ve got the service manual thanks to another great thread but need some guidance.
    I feel like this unit is worth the love.

    Thanks in advance

    Derek
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  2. DerekE

    DerekE New Member

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    Doesn’t have a simple switch mechanism that I can find like my wm-10 which was its issue for not turning on and was easy to find...
     
  3. StaticAudio

    StaticAudio Active Member

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    Sony had (has?) the nasty habit of reversing the polarity of the power adapter input jack, the + is the outside, the - is the inside, whereas other manufacturers mostly had the - on the outside of the pin. When using a non-sony adapter you really have to take care not to fry your walkman...

    You're sure the adapter is the right type?

    Also, the WM7 has an internal DC-DC converter, because the 3V was not enough to power the unit, maybe the converter is broken because of the wrong adapter?
     
    Last edited: Jun 16, 2020
  4. DerekE

    DerekE New Member

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    It’s a period Sony one so all good there. It was the last thing I tried too. Always test off batteries or a battery pack and wires first. I have found a broken wire to the motor. I think the guy I bought it off may have been tinkering inside. As it had a new belt in it but was loose. If you don’t have the diagram you probably would get a bit stuck... Also one of the screws to securing the motor bracket was missing. 9BCF1777-9D79-4E14-B936-09647E91B46F.jpeg
     

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