Issue with AC turntable motor. at 45 rpm Any ideas?

Discussion in 'Audio Hardware' started by DrZhivago, Sep 14, 2021.

  1. DrZhivago

    DrZhivago Hedonist Thread Starter

    Location:
    Brisbane Australia
    Hello,

    My Pro-Ject 6Perspex Turntable AC motor started playing up today. When switched from cold to 45 rpm it refuses to spin and judders. After a couple on-offs it would eventually start spinning, but its 50/50. No issues when my speed-box is set to 33 rpm. It also has no issues when its already running at 33 and then i change to 45. Any ideas what could be wrong here? Has anyone else experienced anything similar with their TT motor?

    Thank you
     
  2. Mr.Sign

    Mr.Sign Forum Resident

    Location:
    Germany
    Hello Dr

    In the manual of my Acoustic Signature TT is written that you have always to start with 33,3rpm , leave it that way for some seconds and then switch to 45 rpm. So in this case it is the normal procedure. For acoustical reasons some TT producer use very weak motors. There are some TT ( Nottingham for example ) that even need a manual touch to start.
    I do not know if this is the case for your TT. Perhaps cleaning the belt , platter etc. might help,. or if it is an old worn belt You might have to replace it.

    Hope that helps,
    Good luck !
     
    DrZhivago likes this.
  3. DrZhivago

    DrZhivago Hedonist Thread Starter

    Location:
    Brisbane Australia
    "Hertzlichen Dank" for your reply.

    Its not the belt issue. The motor is suspended. So I can just take it off the plinth and test without the belt and the rest. As said. It just rumbles when started from "cold" on its own. It will also work if I give it a quick manual spin/flick. It wasn't doing this before. At least not that I can remember.

    Regards
     
  4. vinylontubes

    vinylontubes Forum Resident

    Location:
    Katy, TX
    Do this and then don't worry about it. Modern belt driven motors are low torque for reduced vibrations once they hit their speed target. Yours is struggling to accelerate to the higher speed. You need high torque to accelerate. As it is, that rumbling is beating up your motor's bearing. The fact that it didn't do this before is inconsequential.
     
    DrZhivago likes this.
  5. DrZhivago

    DrZhivago Hedonist Thread Starter

    Location:
    Brisbane Australia
    Took the thing apart last night, and realised that motor shaft is still turning inside the pulley. For some reason. It looks like the pulley plastic became lose/worn and it doesn't grip on the shaft. Or perhaps it was glued/bonded together and it got unglued due to me going from 0 to 45 rpm over the years? Will need to check with the manufacturer if they glue these things together. If they did. I will try some super glue. Lesson learned is that i will start with 331/3 rpm first, and then switch to 45 when playing 45 rpm cut records.

    Regards
     

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