Dual 1228 Tonearm Auto Set-down Problem

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timnor
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Dual 1228 Tonearm Auto Set-down Problem

Post by timnor » 05 Nov 2019 21:12

Dear All,

I have purchased a Dual 1228 and am having problems with the auto tonearm setdown.

Sometimes (1 out of 20 times) it works for 12 inch records.

Most of the time I move the lever to start, platter turns, tonearm lifts, moves towards the record about 1 CM
barely clears the tonearm rest, lowers and then jumps back in the tonearm rest.


If I choose 45 or 33 rpm there is no change in the tonearm movement. In other words the movement
to the 7 inch position doesn't work.

I have taken the unit out of the housing and have checked the white pimple which looks clean.
I cleaned the pimple and the underside of the paddle it is in contact with. I also tried various
adjustments but nothing seemed to help.

I have tried the adjustment mentioned here but am stuck as I don't find nut 60

download/file.php?id=47083&mode=view

Any ideas gratefully received.

mikepick
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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by mikepick » 06 Nov 2019 16:33

I *think* that 60 might be a misprint here, it refers to an adjustment screw that is hidden by the tonearm gimbal.

I make that adjustment using the positioning sleeve (68) which is on the post in front left of the gimbal, it lifts the tonearm up for movement.

Edit: OK, it's not a misprint. There are two operations here. First, adjust for the 2-3mm from the lever using sleeve 68 on the front. Then, with the turntable unplugged, manually initiate the tonearm start cycle. When the tonearm is at its maximum height and starts to move toward the platter, ensure that there is a tiny bit of play between the front post and that back screw (60). Adjust via the silver nut seen next to the tonearm wires here.
518A8108-9BF9-422E-B5EB-A7B3C62904D4_1_201_a.jpeg
(382.95 KiB) Downloaded 106 times

timnor
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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by timnor » 06 Nov 2019 21:49

mikepick wrote:
06 Nov 2019 16:33
I *think* that 60 might be a misprint here, it refers to an adjustment screw that is hidden by the tonearm gimbal.
Thanks a lot. That really explained the adjustment I had to make. I now have those two settings correct.
However it still doesn't work. I've taken the unit out and turned it over and cycled in both 33 and 45.
Upside down I can see that both 33 and 45 work perfectly. But as soon as I turn it over and place it back
in the plinth the arm only moves slightly to the 33 position. I can't work it out !

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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by mikepick » 06 Nov 2019 22:26

Have you or the prior owner had any maintenance done on the unit? After so many years the grease and oil on the various parts gums up and causes it to stick and malfunction as you describe.

Even in the steuerpimpel looks clean, it may have enough wear that it is not gripping enough to steer the tonearm properly to the start position. The dimensions for the pimpel can be found around here I think, might be worth checking to make sure it is not too worn.

Does auto return work, if you manually start a record? Does the tonearm feel like it moves smoothly if you pick it up and manually start a record? Does it track smoothly as a record plays?

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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by timnor » 07 Nov 2019 07:35

mikepick wrote:
06 Nov 2019 22:26
Have you or the prior owner had any maintenance done on the unit? After so many years the grease and oil on the various parts gums up and causes it to stick and malfunction as you describe.

Even in the steuerpimpel looks clean, it may have enough wear that it is not gripping enough to steer the tonearm properly to the start position. The dimensions for the pimpel can be found around here I think, might be worth checking to make sure it is not too worn.

Does auto return work, if you manually start a record? Does the tonearm feel like it moves smoothly if you pick it up and manually start a record? Does it track smoothly as a record plays?
Thanks. I'm not sure about maintenance but inside the unit the grease and oil that is visible doesn't look as dried and gummed up as other units I've had. I will measure the pimple but as mentioned above, with the unit upside down the arm cycles and moves correctly in both 45 and 33. It seems that when I then place the mechanics in the plinth and add the weight of the platter than this results in a malfunction. My suspicion is that with the platter mounted the metal
lever that pushes the black paddle into the correct groove of the yellow plastic disc to enable the arm to swing out is not working.

I also notice that the platter is rubbing the black strobe light unit very slightly.

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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by mikepick » 07 Nov 2019 18:08

One other thing to try is cycling the start sequence with the tonearm locked to the rest, that is supposed to reset the shut-off mechanism.

Platter rub is not normal though, so that is something to look at. It may just be the strobe paper on the back of the platter coming loose, I have that issue with a unit waiting to be cleaned up. The bearing bridge and cam should be snugly attached, but if that were not the case I think you would notice the platter moving in a warped manner.

You haven't mentioned whether it plays a record manually though, have you tried that yet?

I wonder if the pawl (203) is gummed up. That's the first thing the tonearm hits as it moves out, which in turn activates the shift arm (187) that switches on the motor, starting up the platter. If the pawl or the shift arm aren't moving freely, that will hinder the tonearm. The shift arm pivots on the grooved pin (191) and that can often be gummed up as well.

timnor
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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by timnor » 07 Nov 2019 21:28

mikepick wrote:
07 Nov 2019 18:08
One other thing to try is cycling the start sequence with the tonearm locked to the rest, that is supposed to reset the shut-off mechanism.

Platter rub is not normal though, so that is something to look at. It may just be the strobe paper on the back of the platter coming loose, I have that issue with a unit waiting to be cleaned up. The bearing bridge and cam should be snugly attached, but if that were not the case I think you would notice the platter moving in a warped manner.

You haven't mentioned whether it plays a record manually though, have you tried that yet?

I wonder if the pawl (203) is gummed up. That's the first thing the tonearm hits as it moves out, which in turn activates the shift arm (187) that switches on the motor, starting up the platter. If the pawl or the shift arm aren't moving freely, that will hinder the tonearm. The shift arm pivots on the grooved pin (191) and that can often be gummed up as well.
Thanks a lot ! I took a closer look tonight and cleaned the pawl (which wasn't gummed up but had a black oil over it)
but this didn't seem to help. I was about to throw the player out the window in the general direction of the Black Forest when I noticed that the anti-skate spring was not connected. I re-connected it and hey presto everything is working.
I'm not sure I understand why.

I think the scraping is from the strobe paper which has obviously been glued and repaired badly. I pushed it down and it seems to be quiet again. I know there is a strobe to download but I read that this is not suitable for the 1228 ?

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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by mikepick » 07 Nov 2019 22:25

Great! I think I remember seeing the appropriate strobe for the platter in some thread here, you might be able to find it via search. I need to pull it off the one I have, if I can get it intact I will scan it for future reference.

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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by timnor » 08 Nov 2019 22:24

mikepick wrote:
07 Nov 2019 22:25
Great! I think I remember seeing the appropriate strobe for the platter in some thread here, you might be able to find it via search. I need to pull it off the one I have, if I can get it intact I will scan it for future reference.
Grrrrrr. I balanced the tonearm. Finally hooked the turntable up to my amp. Was blown away by the sound of this unit which was almost comparable to my 721 with a JICO SAS. Slight hum which I have to investigate but overall really happy. Played 2 LPs without problem. Set down was almost 100% correct but a few mm too far into the first track so I started adjusting the setdown point with the little screw that is exposed under the speed lever when 45 is selected. Minor turn of the screw and the set down is no longer correct and the swing out for 45s is not working. So I'm back to the original situation with no idea what I did to fix it last time.

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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by mikepick » 09 Nov 2019 23:03

Any luck since? Did you try to set the screw back to what it was prior?

I have a feeling that, even though the deck may look clean, you are not going to get out of this without a teardown and clean-up of the main automatic parts.

It could be that you cured a major problem—I could see how having an anti-skate spring detached might cause the tonearm to be completely unbalanced, maybe—but you probably have a few other things in there that are not moving as freely as they should.

I usually do a clean-up regardless of how well it works—though to be fair I haven't yet got a Dual that worked properly as was. It's not that difficult providing you are aware in advance of a few key danger points, and the 1228 in particular is a very simplified version of the Dual changer mechanism in my experience.

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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by timnor » 10 Nov 2019 08:55

mikepick wrote:
09 Nov 2019 23:03
Any luck since? Did you try to set the screw back to what it was prior?

I have a feeling that, even though the deck may look clean, you are not going to get out of this without a teardown and clean-up of the main automatic parts.

It could be that you cured a major problem—I could see how having an anti-skate spring detached might cause the tonearm to be completely unbalanced, maybe—but you probably have a few other things in there that are not moving as freely as they should.

I usually do a clean-up regardless of how well it works—though to be fair I haven't yet got a Dual that worked properly as was. It's not that difficult providing you are aware in advance of a few key danger points, and the 1228 in particular is a very simplified version of the Dual changer mechanism in my experience.
Thanks Mike

I've been playing around but have been unable to fix the problem. Sometimes I get it to work for a cycle or two
then it fails again. For sure I've found out that when I lightly touch the following part and the metal part upper right this seems to help. By the way should the copper part here be free to move ? This part has something to do with the tonearm movement ? The screw and round metal washer doesn't hold the copper part in one position but limits its movement ? Sometimes the corner pin of the tonearm comes out of this copper housing. Is this normal ?

https://i.ibb.co/LnSWnpt/IMG-20191110-0 ... ER-TOP.jpg

I'm still wondering if it makes sense to strip the unit down further before replacing the pimple. Here is a picture of mine. It looks ok to me but I'm no expert :

https://i.ibb.co/92x1zzv/IMG-20191110-091450215.jpg

Thanks again

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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by DSJR » 10 Nov 2019 10:13

I thought original pimpels were dark grey/black coloured? Worth asking mrow2 Don here for one of his and also a supply of original gadus alvania grease, otherwise to re-grease with other stuff a total strip and clean will be needed to prevent possibility of the lubes reacting chemically with each other (why i always baulked at a once universal recommendation for Superlube, which I'm sure is fine, but maybe not when mixed with the original stuff?).

https://www.ebay.com/itm/Steuerpimpel-f ... 4187657044

Usually, the main lever paddle and pimpel have a kind of love-hate relationship with each other, one part adding friction and the other smoothing it a little. There should be (alvania) grease on the paddle (I think this still applies to the plastic main levers as above) to aid smooth movement and maybe even add some drag to assist the pimpel's 'grip' as well?

I haven't checked, but have you looked at Dualcan's site and service advice? In any event, Don has a very informative printed sheet he supplies with his stuff and this should assist no end.

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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by timnor » 10 Nov 2019 15:27

DSJR wrote:
10 Nov 2019 10:13
I thought original pimpels were dark grey/black coloured? Worth asking mrow2 Don here for one of his and also a supply of original gadus alvania grease, otherwise to re-grease with other stuff a total strip and clean will be needed to prevent possibility of the lubes reacting chemically with each other (why i always baulked at a once universal recommendation for Superlube, which I'm sure is fine, but maybe not when mixed with the original stuff?).

https://www.ebay.com/itm/Steuerpimpel-f ... 4187657044

Usually, the main lever paddle and pimpel have a kind of love-hate relationship with each other, one part adding friction and the other smoothing it a little. There should be (alvania) grease on the paddle (I think this still applies to the plastic main levers as above) to aid smooth movement and maybe even add some drag to assist the pimpel's 'grip' as well?

I haven't checked, but have you looked at Dualcan's site and service advice? In any event, Don has a very informative printed sheet he supplies with his stuff and this should assist no end.
Thanks. I'm in Germany so I ordered one from here

https://www.ebay.de/itm/Steuerpimpel-Gl ... SwuxFY1xS7

I took another look today. Perhaps someone can confirm but when 45 is selected I believe the tonearm pin is
supposed to travel out from the open end of the copper guide shown above. Mine doesn't. I don't see any point
of friction so I am almost convinced that this is simply because the pimple is not doing its job properly.

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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by mikepick » 10 Nov 2019 17:08

The copper piece is the pawl I referred to earlier. There is a pin on the tonearm segment, the sliver diamond shaped piece, that fits in the slot at the end of the pawl.

The way it works, is when the tonearm rotates towards the record, the pin on the segment pushes the pawl downward and sideways, and it catches on the square post. The other end of the pawl has a pin which pulls the long lever that switches the motor on and pulls the idler assembly against the platter.

The tonearm segment pin exits the bottom opening of the pawl when it catches, and then open return it glides in there and pushes the pawl back so that it releases and the long lever springs back to shut off the motor and disengage the idler.

So yes, it needs to move freely lengthwise and sideways a little to catch. The washer is there to hold it up on the post when the unit is right side up. :)

One way to see it working is to put the unit up on four cans (beer, beans, soup, whatever you have), one in each corner, and then you can use a mirror to see it working, if you manually lift the tonearm and move it toward the platter.

It’s hard to diagnose the pimpel from photos, it looks like it may have some wear. You could take a look at the main lever as well. The underside of the paddle that moves the pimpel has a cross-hatch pattern on it, if I remember right. It may be worn, but I would think the plastic ones would be less prone to that.

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Re: Dual 1228 Tonearm Auto Set-down Problem

Post by mikepick » 10 Nov 2019 17:21

timnor wrote:
10 Nov 2019 15:27
Perhaps someone can confirm but when 45 is selected I believe the tonearm pin is
supposed to travel out from the open end of the copper guide shown above. Mine doesn't. I don't see any point
of friction so I am almost convinced that this is simply because the pimple is not doing its job properly.
All that and I didn’t directly address the question, which is that yes, the pin moves out of the opening of the pawl, not only on 45, but on any mode—45, 33, and manual.

So if it bumps up against the pawl and is stopped, it is either not enough friction from the pimpel or too much friction in the levers. I guess that narrows it down. :P

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