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MR67 static and permanent mute

Discussion in 'McIntosh Audio' started by david winter, Nov 5, 2018.

  1. david winter

    david winter Classical music lover. Subscriber

    Messages:
    569
    Location:
    Paris, France
    Hi,

    I'm working on a nice MR67 and found the source of the constant static noise on both channels.
     
    Last edited: Nov 6, 2018

     

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  2. david winter

    david winter Classical music lover. Subscriber

    Messages:
    569
    Location:
    Paris, France
    The problem is the T6 discriminator transformer. One of the internal mica capacitors is bad and leaks. It's not the 33pF accross both coils, but the one in parallel with the primary and sealed between two plastic bases maintaining the pins.
    T6 is reference T-107-135B. It was used by several tuners including the MR71 but McIntosh has no stock (from what I read in some other posts).
    Is there a workaround ?
    I'm considering opening the sealed plastic base, removing the two capacitors, cleaning the black residues and put external ones, but I need the original values. Anyone knows them ? If the second capacitor (accross the secondary) is still ok I can measure it but without the value for the first one I'm stuck unless both have the same value.
    Any advise appreciated. Thanks.
     
    Last edited: Nov 6, 2018
  3. John James

    John James "Bob's your uncle" (Stolen) Subscriber

    Messages:
    8,336
    Location:
    Piney Flats, Tn.
    Have you actually contacted Mcintosh to see if they have it?
     
  4. clinic-audio

    clinic-audio all on YAMAHA untill 1990

    Messages:
    2,182
    Location:
    France
    Hello David

    I can help you , send me a PM
     
  5. mnmmt

    mnmmt AK Subscriber Subscriber

    Messages:
    160
    Location:
    Minnesota
    Audio classics will rebuild it for $100, which I consider a bargain for how delicate, unobtainable, and essential it is.
     
  6. kaplang

    kaplang Works for me ! Subscriber

    I had one rebuilt by audio classic for an MX110. It was well done and well worth the cost.
     

     

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  7. david winter

    david winter Classical music lover. Subscriber

    Messages:
    569
    Location:
    Paris, France
    Thanks for your hints, that's much appreciated. Clinic Audio (who I know well and have helped me rebuilding other McIntosh gear) will take care of it.
    No idea if the other transformers can fail or need to be rebuilt, but at least the sound I get over the static is really nice.
     
  8. kaplang

    kaplang Works for me ! Subscriber

    If it’s not broke, don’t fix it.
     

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