Yamaha CR-2020 dial cord binding

[dbxdx5]

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.

 

[avionic]

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.

View attachment 1305624 View attachment 1305625

Did you try to restring it?

 

[Punker X]

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.

 

[dbxdx5]

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.

 

[dbxdx5]

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.

 

[avionic]

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.

 

[dbxdx5]

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.

 

[avionic]

Good luck. I hate messing with dial cords..

 

[dbxdx5]

Good luck. I hate messing with dial cords..

Thanks. I'm going to go ahead and restring it.

 

[dbxdx5]

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?

 

[amptramp]

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.

 

[dbxdx5]

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.

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.

 

[dbxdx5]

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]

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.

Outstanding.. I knew you could pull it off.