Dual 1019 tonearm return troubles

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lukef240
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Dual 1019 tonearm return troubles

Post by lukef240 » 15 Apr 2018 21:30

Hi folks, first time poster here. I'm having a problem with the tonearm on my 1019 dragging about 3/4" across the record run out at the end of play before lifting and returning to it's rest. If I manually select stop during play, all is well (lifts properly and no dragging). I was thinking this might be a steuerpimpel issue, but wonder why the problem only occurs at the end of the record.

Any suggestions would be very much appreciated!

dualcan
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Re: Dual 1019 tonearm return troubles

Post by dualcan » 16 Apr 2018 03:41

Hi and welcome!
The problem can still be the pimple but it is mostly the surface of the main lever that is too smooth from wear.
In the library above you will find the 1019 service manual and in the blow up on this page:
1019.jpg
you will see that the main lever (item 191) and the pimple (item 208).
The main lever surface that touches the pimple is sandblasted-rough when new. This roughness wears smooth from the pimple over the years an must be re"roughened". This can be done with some mid-grade (100/120 grit) sandpaper which must be applied in a few sharp strokes to the main lever, perpendicular to pimple movement.
This will leave some mild tracks for the pimple to grab on to. The pimple if worn too much, can be replaced by the one sold by Revisound:
https://www.ebay.de/itm/Steuerpimpel-fu ... Swol5YzBvK

Once the main lever is roughened and the new pimple(or useful old one) is re installed, it is vital to smear a very thin layer of grease on that contact surface to avoid wearing the pimple.
I know it sounds implausible to put grease on the area that should have friction, but that is what the sand blasting/sanding does- provide friction. The grease film protects the pimple from premature wear because every time the changer is engaged (Start) the very first movement of the main lever is a full drag over the motionless main lever.
You may also want to look at the full restoration of the 1019 and other Dual on my webpage under service tips, available via the "blue ball/Earth symbol" to the left.
Regards,
k

lukef240
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Re: Dual 1019 tonearm return troubles

Post by lukef240 » 16 Apr 2018 05:19

Thank you very much for the info, dualcan. A bit of history - this table is one that I assembled from the better parts of two auction site "specials" last October and has worked quite well since. I could not have begun to do so without the resources you and this site have already given me! At the time, I gave the main lever surface a cursory 180 - 200ish scuffing (the stuerpimpel "looked" fine). I'll try some 100 grit and a fresh swipe of grease tomorrow and report back. Thanks again for the info!

lukef240
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Re: Dual 1019 tonearm return troubles

Post by lukef240 » 16 Apr 2018 21:53

Well, after re-scuffing the main lever surface with 120 grit the table is exhibiting the same symptoms. Though the stuerpimpel "looks" as if it's OK, it is most certainly worn below the 1/16" thickness that I've read is the proper thickness. I'll order a replacement (thanks for the link, dualcan!) and report back.

In the meantime, I'm open to any other ideas you may have. Again, the problem only occurs in automatic mode and only in the record run out grove. I can manually hit the stop lever while near the end of the last track and the arm lifts and retreats fine.

Thank you very much for the Help. Admittedly, I enjoy tinkering with this turntable almost as much as I enjoy listening to it!

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Re: Dual 1019 tonearm return troubles

Post by mrow2 » 16 Apr 2018 22:43

I wonder about the coarseness of the grit at something like 120. It might wear that mushroom steuerpimpel right down. I have not roughed up any of my 1019s or 1209s on hand and they work just fine but if I did want to increase traction I might try a crosshatch at 400 grit or perhaps 220 grit, smear the grease and see how that does. I am thinking that an older worn mushroom could be built up after cleaning and then using some white Delrin and a solder iron, then rounding it to the desired mushroom form. This would take some practice though. At some point I will try it. What shaping I have done with Delrin has been successful; it works well and I am looking forward to trying it again.

dualcan
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Re: Dual 1019 tonearm return troubles

Post by dualcan » 17 Apr 2018 00:14

Hi,
The grease is there to mitigate the rough surface of the original sandblasted main lever. Grit 400 down to 220 only smooths the surface for these pimples, unfortunately. The pimple on all 1000 series is not made of rubber but vinyl. I have not tried to rework that pimple yet, simply because I still have some original stock. I would be curious how your experiment with the Delrin goes over a longer period of time, however. I would have thought that the material (old/new) would not fuse properly. The preferential way is to replace the pimple with a complete rebuilt, I would think, but never say never! We also had an IKEA solution way back when....
As far as the transport only being poor in the run-out area, it is a clutching problem, but might also be miigated by cam wear. At the beginning of the cam track (wherein the main lever runs) the incline slope (for main lever) and subsequent level run in that groove, sees the edge most worn by main lever scraping because of a dried (lube) cam. This is readily apparent when the original (black) molycote graphite grease was used. It is possible that the wear in that area (since it is the first contact area in all auto cycling), lowers the main lever just a tad and in combination with poor pimple and too slippery main lever, all combining to give poor traction on that spot (green line 2 edge).
1219 Cam sectional travel.JPG
Keep in mind that any activation of auto cycling as the above pic shows, involves the same cam rotation. It does not matter if it's Start, Stop, Repeat (as in next record) or end shut off. This is why I am more inclined to believe the main lever/pimple clutching to be at fault.
Have a look at that precipice on the cam's slope for wear anyways, especially if Molycote was still used instead of the Alvania.
Just for info sakes, the Molycote grease is a slipperier lube and actually better suited for the cam, however, it dries out from about five years on. That's when the stuff turns into scraping/sanding material instead of lube. Alvania is far better in longevity and still works fine after forty or so years. The cams that had Moly usually needed changing whereas the Alvania just needed cleaning and showed zero wear. That was the case already when I was still working at Dual-- many years ago!
Regards,
k

lukef240
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Re: Dual 1019 tonearm return troubles

Post by lukef240 » 17 Apr 2018 04:25

Interesting thought with the Delrin, mrow2. Thanks. As I've already ordered a replacement stuerpimpel, I was thinking I might try the down and dirty epoxy / file to profile treatment until the new part arrives just to satisfy my curiosity. I'll try to do this tomorrow if time allows.

As for the cam, dualcan, I picked the better of the two cams I had between the two machines. One had several black pits visible on the #2 ramp and the other was spotless after cleaning... I feel certain that I used the better one, but perhaps it's worth a look!

Thank you both for the suggestions and to show my gratitude, here's a link to a video I made of the old girl talking to the Tektronix back in her better days -

https://www.youtube.com/watch?v=einYb7HXxN8

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Re: Dual 1019 tonearm return troubles

Post by DSJR » 17 Apr 2018 17:09

I couldn't 'get' the inference of the arm skating across the record before lifting off.

The dragging could be sticky trip pawls on the cam. Forgive my terminology here, but the tonearm segment underneath is attached to the main trip 'slider' which is pivoted at the arm end and runs on a ball bearing under the platter to nudge the trip parts/pawls on the cam at the platter end to engage the mechanism. A guide as to how a velocity trip works is a sticky on the UK vintage radio side in the record player/HiFi 'room' and explains how the system works for popular auto turntables. These (fine and delicate on the Dual cams) parts should pivot and slide against each other very freely* and if they're sticky through inadvertent lubrication, the arm won't track at side end and will be inclined to 'stick' especially on run-out record grooves. The pimpel and main lever operation will have nothing to do with it I feel, as on Duals, the arm is smartly lifted before being urged to move back to the rest.

Forgive me if I have the above totally wrong. My 1019 auto mechanism at 33rpm, lifts the arm smartly, moves it back to the rest fairly gently but smoothly and again the movement back to the record indexing point is smooth and gentle before a fairly abrupt but smooth lowering to the disc if the cueing device isn't set first. When the arm is balanced out to 'zero,' there should be perfectly free movement from the rest to the near spindle end-stop. Mine had a slight stiction halfway along and it turned out to be the bias(anti-skate) spring catching slightly as the tonearm bearing was rotated.

Good luck.

* I got into 'school-ma'am mode regarding a CS515 on which the restorer smeared a little grease on the pawls as it seemed this was done on the originals when I suggested leaving these parts free and dry. Klaus recommended the tiniest spot of damping fluid (as used in the cueing device) on the *pivot* only on the 1219/1229, to stop excessive rattle and possible rebound at the 78 speed on these models (not sure the pivot friction of these parts is quite as low on other models capable of 78rpm use). I've seen too many Garrards of all ages where oil was used here in manufacture and after twenty years and more, this oil dries out, seizes these parts and all but jams the arm near end of side.

lukef240
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Re: Dual 1019 tonearm return troubles

Post by lukef240 » 17 Apr 2018 22:26

Fixed and working like a charm now!

I believe the culprit may have been sticky trip pawls (thank you DSJR). Before any attempt to build up the stuerpimpel, I wanted to rule out any cam issues. I removed the cam, inspected the ramp area and removed the pawls as they were sticky with a very light coat of grease! I cleaned them in alcohol and let them dry thoroughly. I reinstalled them dry and she now works like a charm. Though I don't recall applying grease to them back in October when I first rebuilt this table, I must have...

Thank you all for the Help - I hope I can return the favor someday.

Luke

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