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Yamaha CR-2020 dial cord binding

Discussion in 'Tuners' started by dbxdx5, Oct 14, 2018.

  1. dbxdx5

    dbxdx5 AK Subscriber Subscriber

    Messages:
    2,792
    I'm starting with you guys before I pose this in the Yamaha sub-forum.

    I have a Yamaha CR-2020 in front of me with a binding dial cord. It will go all the way to the left, but only about 2/3 of the way to the right (on the dial) before a jam occurs at the point where the cord comes off the flywheel toward pulley 4 and winds on to it from pulley 5. Somehow I've managed to avoid having to deal with many tuner dial cord issues all these years. . . . until now. o_O

    CR-2020 Dial Cord Routing.jpg Dial cord.jpg
     

     

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  2. avionic

    avionic " Black Knights " Subscriber

    Messages:
    43,656
    Location:
    Fort Dodge, Iowa
    Did you try to restring it?
     
  3. Punker X

    Punker X Moderator Moderator Subscriber

    Messages:
    3,986
    Location:
    Panic in Detroit
    Concur restring.. take off the old and make sure the front-end or any of the pulleys are not binding. I would leave the pointer disconnected and restring. Make sure the front-end goes from fully open to fully closed. Then attach the pointer. More than likely the the front-end will need realignment for the scale to be calibrated correctly.
     
  4. dbxdx5

    dbxdx5 AK Subscriber Subscriber

    Messages:
    2,792
    I haven't tried restringing it yet. It's odd: There was no issue until after I replaced the bulb in the pointer. This required raising/tilting back the metal plate where the cord is attached by about 3/4".

    It seems as if the issue is in how the cord is wrapping on the flywheel at the problem point, causing it to bind on itself. I found that if I pull back the cord between pulley 5 and the flywheel while trying to turn the tuning knob, the pointer will move freely.
     
  5. dbxdx5

    dbxdx5 AK Subscriber Subscriber

    Messages:
    2,792
    Is it possible to tighten the cord via the tension springs? I ask because it appears that the cord isn't laying flat on the flywheel right before the jam occurs, which says loose to me.
     
  6. avionic

    avionic " Black Knights " Subscriber

    Messages:
    43,656
    Location:
    Fort Dodge, Iowa
    Possibly the rust/corrosion on the flywheel spindle is also contributing to the dilemma.You can try to apply a little more tension with the spring.The dial cord may have gotten twisted while messing with the pointer.
     

     

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  7. dbxdx5

    dbxdx5 AK Subscriber Subscriber

    Messages:
    2,792
    Thanks Avionic. I can't see how I would have introduced any twist into the dial cord. I think it's just past its prime. I'll see if adding a scooch more tension at the spring helps.
     
  8. avionic

    avionic " Black Knights " Subscriber

    Messages:
    43,656
    Location:
    Fort Dodge, Iowa
    Good luck. I hate messing with dial cords..
     
  9. dbxdx5

    dbxdx5 AK Subscriber Subscriber

    Messages:
    2,792
    Thanks. I'm going to go ahead and restring it.
     
  10. dbxdx5

    dbxdx5 AK Subscriber Subscriber

    Messages:
    2,792
    An AK search shows me two different suggestions for replacement dial cord: #6 unwaxed bead cord or 30lb. test Dacron braided fishing line. Any thoughts on which is more appropriate for a Yamaha CR-2020?
     
  11. amptramp

    amptramp Active Member

    Messages:
    400
    Location:
    Mississauga Ontario Canada
    There are two ways to loop a cord around a tuning shaft, with the cord being wound so it approaches the front or rewound so it approaches the rear. This looks like a case of it being the wrong way. I don't think you need new cord, just rewrap it in the same direction but the opposite direction from front to back.
     

     

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  12. dbxdx5

    dbxdx5 AK Subscriber Subscriber

    Messages:
    2,792
    Thanks. I re-looped the cord to confirm that as it comes up from pulley 4 the first wrap around the flywheel shaft is toward the front of the receiver. That's what I'm seeing in the SM diagram. It's still binding.
     
  13. dbxdx5

    dbxdx5 AK Subscriber Subscriber

    Messages:
    2,792
    Ok, did the restring. The old cord measured nearly two inches longer than the spec in the SM. Some of the slack was being taken up by a second spring someone rigged inside Pulley 1. In addition, Pulley 4 was binding a little because its shaft was seated in too far. Now we have smooth, consistent movement of the dial pointer again.
     
    avionic likes this.
  14. avionic

    avionic " Black Knights " Subscriber

    Messages:
    43,656
    Location:
    Fort Dodge, Iowa
    Outstanding.. I knew you could pull it off.:D
     
    dbxdx5 likes this.

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