Pioneer PL-518X Motor Rumble?

Discussion in 'Turntables' started by neevo, Jun 12, 2018.

  1. neevo

    neevo Super Member

    Messages:
    1,156
    Location:
    Sydney, Australia
    On lead in grooves I get a distinct sound from my TT and wondering what it could be and if I could fix it.

    It sounds like a whooshing, rumble sound that is then masked by the sound of the music.

    The motor had a noticeable scrape sound coming from it at one point so I took it apart, cleaned it and added a touch of oil. Scrape sound seems to have gone but I want to make sure this rumble is either from the motor and can be fixed or is within an acceptable level.

    The fact I hear it makes me think it’s not, however I cannot guarantee it’s the motor.

    TT is on a heavy stand and on a concrete floor so likely not related to feedback.
     

     

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  2. neevo

    neevo Super Member

    Messages:
    1,156
    Location:
    Sydney, Australia
    Doesn’t look like many here have played with the motors. I also cannot find an exploded view of what they should look like either.

    Spinning the platter on its own I’m hearing a noise that seems like it could be the source. A grinding/scraping noise that I would assume shouldn’t be there, although admittedly I have my ear right on the edge of the platter.

    Does anyone know about these motors?

    I have pulled the motor apart before, cleaned it, oiled it and put it back together. It was a great fit and didn’t bind at all and kept a pocket of air underneath the spindle as it inserted into the bottom half. There wasn’t a ball bearing or similar between the 2 halves. Anything unusual going on there?
     
  3. neevo

    neevo Super Member

    Messages:
    1,156
    Location:
    Sydney, Australia
    Doing some more reading I think it looks like the 518 motor runs on a thrust disc. I will pull apart the motor and see if I can see any issues with what the spindle is running on. I assume if it’s rither dirty in there or the disc is missing this would cause a noise on the bottom of the spindle which would resonate through the platter.

    Will post updates when I have them.

    If it is the thrust disc, you cannot buy replacements for the 518, so I’ll look to buy some delrin off eBay and turn it up to the correct diameter with a dimple in it on the lathe.
     
  4. Montycat

    Montycat AK Subscriber Subscriber

    Messages:
    16,715
    Location:
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    I expect you are on the right track. I researched some too and came across similar results. I have experimented with pieces of yogurt lids and similar things in spindle wells with varying success. However none of those were direct drive motors.
     
  5. neevo

    neevo Super Member

    Messages:
    1,156
    Location:
    Sydney, Australia
    Interestingly I cannot find any info online about it either. I can’t believe I’m a Pioneer ( get it ;) ) on this but it certainly looks like no one has documented the process yet.
     
  6. neevo

    neevo Super Member

    Messages:
    1,156
    Location:
    Sydney, Australia
    Popped the top of the table tonight to see if I could see what’s going on:

    E94A7109-7E91-4C68-B715-B952AEE7789F.jpeg

    I pulled the top part of the motor and cleaned it with tissue, making sure the spindle was as clean as possible and I couldn’t feel any gouges or scratches (I couldn’t).

    I then checked inside the spindle hole to see if I could see the thrust bearing:

    4C235E23-A2ED-4E25-A1CB-486F73B609EE.jpeg

    As you can see it’s perfectly in tact and looks almost brand new. The dimple is still present.

    So given the condition I simply cleaned it and added a drop of oil. I noticed as I sat the motor on top again it floated on an air bubble.

    Pushing it down a little I was able to button it up and ran it. There’s still noise but it’s very quiet and I suspect zero noise for a motor is impossible but it certainly seems quieter.

    Will spin some records and see how it sounds.
     

     

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  7. tom67

    tom67 Active Member

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    Location:
    Palm Beach Gardens FL
     
  8. bimasta

    bimasta Super Member

    Messages:
    2,170
    You describe "grinding and scraping". Grinding is consistent with a very bad motor. But scraping is usually something else. You've checked that nothing else is rubbing, scraping?
     
  9. neevo

    neevo Super Member

    Messages:
    1,156
    Location:
    Sydney, Australia
    It’s hard to describe. All I know is the motor is not perfectly silent even when I spin it by hand. Should it be?

    At one point I thought it was the paint on the motor blades which had bubbles and I thought they were touching the magnet, so I gently sanded them off, but it didn’t change anything.
     

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