Stylus pressure adjustment wheel (on tonearm) won't hold position

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analoged
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Stylus pressure adjustment wheel (on tonearm) won't hold position

Post by analoged » 16 Dec 2018 13:51

hold position/setting.
help...
Is the "needle" the only thing responsible for keeping the setting in place?
Also,where do you orient the wheel if replacing?
Has anyone dealt with this problem before?
I ended up replacing the whole arm assembly (601) some time ago,but I am thinking there is nothing wrong with the removed arm itself.
Now I have a 1249 with the same affliction.What am I missing here?

dualcan
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Re: Stylus pressure adjustment wheel (on tonearm) won't hold position

Post by dualcan » 16 Dec 2018 17:30

Hi,
It is always a good idea to go to the service manual (in the library above) and mention which Dual and the item numbers shown in the isometric drawings at or near the end in every manual, for the parts you are referring to. That way a false response can be avoided.
Regards,
k

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Re: Stylus pressure adjustment wheel (on tonearm) won't hold position

Post by analoged » 16 Dec 2018 18:48

Both 601 and 1249
No. 78 (1249) and 59 (601)
Thanks.
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musicmn
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Re: Stylus pressure adjustment wheel (on tonearm) won't hold position

Post by musicmn » 16 Dec 2018 18:57

Hi, Ive had quite a few of these type of Duals come across my bench in the last year that have had this same issue. And what I found is that the tonearm bearing housing on the side of the tonearm where the tracking force adjustment wheel is breaks from age and the stress of the coil spring used in the tracking force adjustment. The part in question is called a Frame I believe and if you check my pictures you can see what happens. In the first three pictures you can see the broken bearing housing. For some reason Dual made this part out of plastic and at this time it just fails. The bottom picture is how this bearing housing should look and you can see the the notch in it for the coil spring to attach to and this frame is made of metal. This notch is needed so when you turn the adjustment wheel the coil spring can windup and put downward pressure on the tonearm. With out this notch and the housing housing in tact the little ball bearings and race fall out. The coil spring cannot be wound up and the entire assembly on that side of the tonearm will be loose and will move around. I currently have a 1242 sitting here with the same problem and I have been waiting for a similar model to show up with a good tonearm but bad cosmedics . And low and behold a 1247 showed up on my local CL that had been stored in a shed and had been used by mice for a home. The tonearm is good but it will need a rewire since mice love to eat the coating on wires. I did order a tonearm from organdonorparts.com earlier this year for a 1247 I was working on at the time. But that tonearm was also broken in the same area. They did have another tonearm for 1247 available that one was good and I did install that one and it worked fine. I checked everywhere on the web for just that frame part but it's not available anymore. So your only choice is try and find a different tonearm and hope it's in good shape so you can use it.
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T68
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Re: Stylus pressure adjustment wheel (on tonearm) won't hold position

Post by T68 » 16 Dec 2018 19:09

Hi!
I got a 601 on which the VTF adjustment still works as it should. But reading this and viewing those pics I get a bit worried that this part will break on my deck too.

Is there any precautions to make that will prevent that from happening?

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Re: Stylus pressure adjustment wheel (on tonearm) won't hold position

Post by analoged » 16 Dec 2018 19:38

Well, the 601 arm isn't broken.Haven't taken 1249 apart yet.
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Re: Stylus pressure adjustment wheel (on tonearm) won't hold position

Post by dualcan » 16 Dec 2018 19:59

Hi,
assuming that the bearing screw 79:
bearing and dial.jpg
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is tight onto the (yellow) metal plate of the dial, then another problem that happens over the years of use, is that the stopper nose of that yellow plate wears the (red) plastic surface , allowing the dial to slip under the nose.
As a rudimentary fix, the nose can be gently persuaded (bent) towards the plastic giving more "grab" at the point of the nose, however the wear will now be more pronounced on the tip of the nose, so "dialing" in too often will speed up wear. I have tried to insert some material but since the plate is riveted into the dial, this has been ineffective.
The dial MUST be removed to perform this "hammering" fix, otherwise the whole shebang will be destroyed...

In regards to the broken dearing ring for the 721 and later units, that ring is plastic. I never had one break because of time related issues as the usual cause has been clients "spearing" the bearing with the bearing screw, missing the centre and destroying that edge.
For the 701 and 601, these dearing ring parts are metal, however incorrect bearing insertion will still kill the race way, so be careful when re assembling!
Regards
k

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Re: Stylus pressure adjustment wheel (on tonearm) won't hold position

Post by analoged » 16 Dec 2018 20:26

musicmn wrote:
16 Dec 2018 18:57
Hi, Ive had quite a few of these type of Duals come across my bench in the last year that have had this same issue. And what I found is that the tonearm bearing housing on the side of the tonearm where the tracking force adjustment wheel is breaks from age and the stress of the coil spring used in the tracking force adjustment. The part in question is called a Frame I believe and if you check my pictures you can see what happens. In the first three pictures you can see the broken bearing housing. For some reason Dual made this part out of plastic and at this time it just fails. The bottom picture is how this bearing housing should look and you can see the the notch in it for the coil spring to attach to and this frame is made of metal. This notch is needed so when you turn the adjustment wheel the coil spring can windup and put downward pressure on the tonearm. With out this notch and the housing housing in tact the little ball bearings and race fall out. The coil spring cannot be wound up and the entire assembly on that side of the tonearm will be loose and will move around. I currently have a 1242 sitting here with the same problem and I have been waiting for a similar model to show up with a good tonearm but bad cosmedics . And low and behold a 1247 showed up on my local CL that had been stored in a shed and had been used by mice for a home. The tonearm is good but it will need a rewire since mice love to eat the coating on wires. I did order a tonearm from organdonorparts.com earlier this year for a 1247 I was working on at the time. But that tonearm was also broken in the same area. They did have another tonearm for 1247 available that one was good and I did install that one and it worked fine. I checked everywhere on the web for just that frame part but it's not available anymore. So your only choice is try and find a different tonearm and hope it's in good shape so you can use it.
This looks more like abuse.I don't think the spring force could be enough to cause this damage.
By the way,I cleaned the wheel for the 601 with alcohol and slightly bent the "needle" to apply more pressure and setting seems to hold.Sure wish I had tried this before swapping out the arm,but I didn't have Dualfred's nice bearing adjust tools then either,live and learn...
But,the 1249 "needle" does not afford the ability to bend it,so,not sure how to increase pressure on wheel.

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Re: Stylus pressure adjustment wheel (on tonearm) won't hold position

Post by musicmn » 16 Dec 2018 21:00

When I see five turntables in the same year from four different customers that all have this same problem. That's not abuse that poor design on duals part. You don't need to disassemble that side of the tonearm to see the broken parts. Just use a bright flash light and look into the inside on the adjustment wheel. You should be able to plainly see the broken bearing holder. And the adjustment wheel will not stay on any setting and it will also just spin around and like I said that hole area will just move around. It should be tight with just a very small amount of movement.

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Re: Stylus pressure adjustment wheel (on tonearm) won't hold position

Post by analoged » 17 Dec 2018 01:43

musicmn wrote:
16 Dec 2018 21:00
When I see five turntables in the same year from four different customers that all have this same problem. That's not abuse that poor design on duals part. You don't need to disassemble that side of the tonearm to see the broken parts. Just use a bright flash light and look into the inside on the adjustment wheel. You should be able to plainly see the broken bearing holder. And the adjustment wheel will not stay on any setting and it will also just spin around and like I said that hole area will just move around. It should be tight with just a very small amount of movement.
Sounds like multiple Ebay shipping disease victims...

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