Dual CS 1268 33-45 lever not moving belt sufficiently both directions

[hrtattckcity]

I've got manual operation working, and managed to replace the steuerpimpel and clean some crusty grease tog et the auto-return functioning.

Next on the agenda is to fix the 33/45 speed change mechanism. The lever does not appear to be travelling dar enough to move the belt sufficiently in both directions--it will reliably move in one direction (i think 33>45) but not back the other way.

Any thoughts on how to solve this?

Thanks in advance!

 

[Tim D]

I've got manual operation working, and managed to replace the steuerpimpel and clean some crusty grease tog et the auto-return functioning.

Next on the agenda is to fix the 33/45 speed change mechanism. The lever does not appear to be travelling dar enough to move the belt sufficiently in both directions--it will reliably move in one direction (i think 33>45) but not back the other way.

Any thoughts on how to solve this?

Thanks in advance!

From my experience with belt drive Duals they have a white plastic speed selector fork under the platter. On my Dual 506 with the same problem one of the tines on the fork had broken off making it only able to change speeds in one way but to not return back to the previous speed. I found a bunch of models used the same fork. I can’t remember if yours was one of them. I found the same part from one of the other models for about 12 bucks on the big auction site.

 

[Tim D]

The service manual for the 1268 can be found on vinylengine.com and it is a free register to get in. The 1268 from the blurry diagram from the service manual seems to have the fork, but they are not calling out the individual part number in this service manual but instead it looks like an assembly part number with a couple of parts and a spring. For this reason I can't confirm it is exactly the same part and whether it is interchangable with the other Duals that I had researched when fixing my Dual 506. If you can pull the platter off and verify that is the part that is broken we might be able to help further. Assuming you need that part it is a little tricky to replace because of springs that are attached, but if you are handy you should be able to do it.

I know I'm getting ahead of my self, but once you are in there replacing parts you should probably remove all the old grease and oil and replace the lubrication. It's probably overdue. After fixing and lubing it you may be done for another 30 years.

 

[Montycat]

An old belt and sagging suspension can contribute to this. The belt gets stretched and more easily deflected without moving much by the "fork" (part 45). If the rubber motor suspension is kind of collapsed the pulley might also be riding a bit low. That can make the fork not readily access the range it needs to work. The fork is not adjustable though might benefit by a drop of light oil (don't get it on the belt) but the pulley height is. According to the SM it should sit 26.4mm from the plinth surface to the top. There will be a small flathead screw under the barrel shaped section.

https://www.vinylengine.com/library/dual/cs-1268.shtml

 

[hrtattckcity]

Thanks both for the thoughts--it gave me some other things to google, and I found an interesting thread on vinyl engine, where the newness of the belt was believed to be the culprit.

It also made me spend a little more time investigating the mechanism--when the belt is removed, and the arm moved to engage the platter, I could test that the white fork that moves the belt up and down moves quite a bit. It moves significantly more than when the belt is on--so I am wondering if the new belt I put on is creating too much resistance. I will wait to see if it breaks in a bit.

gratuitous markup of mechanism attached:

 

[Tim D]

Yes, if the fork is not broken and the mechanism is working freely then it might be the belt is not quite right. They are sensitive to the right size and tension of belt. There are aftermarket belts that have exhibited these problems in the past. Not sure if a break-in period would help.