TD 125 no power to motor?

Discussion in 'Hi-Fi and General Audio' started by mjp200581, Mar 20, 2011.

  1. mjp200581

    mjp200581

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    Hi All,

    I recently bought a Thorens TD 125MK2 of a friend who had had it in storage for a few years.
    The turntable does not work and as far as I can establish there is no power to the motor.

    For those knowledgeable in such things:
    I have cleaned the speed adjustment switches and I have adjusted the phase 1 motor adjustments as per the service manual.
    I seem to have no reading at the voltmeter between ge and b1 solder points when trying to adjust phase 2.
    Any ideas? Can anyone recommend a thorens repairer?
     
    mjp200581, Mar 20, 2011
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  2. mjp200581

    Cable Monkey

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    Before you do that, are the pair of large electrolytics on the main PCB original? If they are swap them out for new ones and check again. Should be cheap to do and is the most obvious point of failure.
     
    Cable Monkey, Mar 21, 2011
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  3. mjp200581

    mjp200581

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    That's pretty much the conclusion I was coming to myself. I've just been quoted £280 plus parts for a professional repair. I trust the repairer will make it better than new but as it's already knackered I may as well take a gamble and replace the capacitors myself. I tried to purchase some caps from Maplin today but came away empty handed after being totally baffled with choice. What type of caps should I buy? The writing on the originals says: 1000MFD 25v 85 C
    The sales assistant in Maplins thought that 1000MFD was an usual rating so I wasn't confident about getting the right thing. I have since checked at they are definitely marked as above. Can anyone confirm what type and rating of capacitors I need?
     
    mjp200581, Mar 21, 2011
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  4. mjp200581

    Cable Monkey

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    1000 MICROFARADS, 25 VOLTS 85 CELCIUS. Seems perfectly sensible to me. It is ok to use a higher voltage and a higher temperature rating wouldn't hurt (though not necessary as the board runs quite cool). Should only cost pennies. I think the originals were silver and look their age. Make sure you get the polarity right and at the very least it should confirm if anything more needs doing. Consider changing any other electrolytics on the board too. Their age and the period of inactivity will almost certainly have rendered them suspect.

    At the price quoted your repair shop could buy an entire table guaranteed working, scrap the rest, swap out electrolytics on the board and still make a tidy profit. If push comes to shove do the same. Buy a worker, swap out any undesireable bits and put the remnants on ebay describing the fault.
     
    Cable Monkey, Mar 22, 2011
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  5. mjp200581

    mjp200581

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    I bought some capacitors at Maplins today for the princely sum of 88p!
    I'll replace the two big electrolytic caps and then see what happens.
    (The confusion over the ratings was because the original caps have 1000MFD written on them rather than 1000mFD (m for micro). I've checked and I'm certain I've got the correct rating now).
    Wish me luck!
     
    mjp200581, Mar 22, 2011
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  6. mjp200581

    Cable Monkey

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    Good luck!
     
    Cable Monkey, Mar 23, 2011
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  7. mjp200581

    mjp200581

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    OK here's an update:
    I tested the DC voltage across all of the capacitors with the following results:
    C2 17.37v, C3 17.48v, C4 17.97, C5 17.84, C6 0.30, C7 4.80, C8 0.00, C9 0.49, C10 0.45, C11 0.00, C12 0.00, C13 0.00, C14 0.00 All results with speed setting at 33rpm.
    Would this suggest the fault lies elsewhere other than the two big caps C2 and C4?
    As yet I haven't replaced any components.
     
    mjp200581, Mar 24, 2011
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