Dual 1218 Auto Start Issue

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mikepick
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Dual 1218 Auto Start Issue

Post by mikepick » 19 Sep 2018 14:24

I'm working on a 1218 at the moment that I picked up locally. Seems like someone had tried to "service" it before and as a result, it was clean, but un-lubricated, assembled incorrectly, and missing a few parts.

Anyway, with some lubrication and reference to the Service manual, I've got it mostly running now. Manual play and auto return work just fine.

A nagging issue is that auto-start does not function properly, the tonearm does not make it all the way to edge of the record. It seems to me that it is hanging up on pawl 243, which pulls the big switch lever to engage the motor. If I give the head shell a nudge as it hangs there it will continue to the edge of the record.

I'm wondering if the steuerpimpel is the problem, but it looks ok.
IMG_9208.jpg
When I start the turntable manually, I can feel the effort it takes to trip the pawl, it's very little but it is noticeable. The switch lever has been cleaned and lubed and seems to me to move well. The little pawl has been frustrating. When I first looked at the table it was not assembled in such a way that the pin on the tonearm plate engaged with it, and it's taken some time to get it to fit right and move relatively freely.

And one other minor question: does anyone know how this torsion spring is meant to fit? It's below the cuing lever, but it doesn't seem to be doing anything at the moment.
IMG_9209.jpg
Thanks, Mike

mikepick
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Re: Dual 1218 Auto Start Issue

Post by mikepick » 19 Sep 2018 15:10

Argh! Reading a thread at another forum this morning, and I've discovered that I'm missing tension spring 192, which connects to the tonearm "segment complete". :x

It can be seen attached to a hole and going under a plate at the bottom of this picture:

https://www.vinylengine.com/turntable_f ... &mode=view

mrow2
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Re: Dual 1218 Auto Start Issue

Post by mrow2 » 19 Sep 2018 23:42

You can see why these are so hard to diagnose from afar. I've found a lot of issue solutions over the years by making comparisons like this, it's great when it can be done. Now you can smooth over the previously dressed main lever paddle a little bit to make sure it's not over-wearing the steuerpimpel.

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Re: Dual 1218 Auto Start Issue

Post by mikepick » 20 Sep 2018 00:42

mrow2 wrote:You can see why these are so hard to diagnose from afar. I've found a lot of issue solutions over the years by making comparisons like this, it's great when it can be done. Now you can smooth over the previously dressed main lever paddle a little bit to make sure it's not over-wearing the steuerpimpel.
Indeed, I mostly hope to not get get a remote diagnosis but hopefully to jar some information loose that might Help me find a different way to think about it.

I'm not sure that the missing spring is the problem, however. In looking at the mechanism in the mirror, it seems like the spring connects the anti-skate mechanism to the tonearm, and so anti-skate is effectively non-existent here. Which might explain why I have had the occasional skip right at the start of records on this deck.

I'm going to go over the start lever again when I get a chance a see if I can get that pawl working a little more effortlessly. I'm interested in hearing from other 1218 owners about how it feels on manual start; as I say, I can definitely feel resistance when tripping the pawl on manual start...

mrow2
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Re: Dual 1218 Auto Start Issue

Post by mrow2 » 20 Sep 2018 17:44

You mean by holding the arm and tripping the motor on as headshell passes the rim of record? There would be resistance at that point, to trip the motor switch assembly manually. It is negated in auto-play.

But regarding the trip pawl at end of record you would not normally feel any resistance there.
For some reason there's some resistance in the lateral tonearm movements toward the beginning of set down and play, if the auto is still not bringing the tonearm to the record. Examine the entire 248 & 249 (ball) trip lever assembly. Look for anything underneath that might be dragging on the underside of the deck itself and causing friction or resistance. So hard to visualize exact issue!

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Re: Dual 1218 Auto Start Issue

Post by Patrice Brousseau » 20 Sep 2018 22:22

My 1215 had First a similar problem: there was a point of resistance when starting in manual mode (and it's still there but normal as DualCan told me). The auto function was unable to drop the arm past this same point of resistance.

It was page twelve fig.18 in the service manual of your 1218 I think.

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Re: Dual 1218 Auto Start Issue

Post by mikepick » 20 Sep 2018 23:30

mrow2 wrote:You mean by holding the arm and tripping the motor on as headshell passes the rim of record? There would be resistance at that point, to trip the motor switch assembly manually. It is negated in auto-play.
To Help visualize, the pawl in question is labelled 243 here:

https://www.vinylengine.com/turntable_f ... &mode=view

But that's a good point, the start lever engages the motor, and so maybe it should be pushing the pawl out enough that it does not catch the tonearm? Right now it doesn't...

FWIW, the trip pawl for the runout is fine. I should check the ball and trip lever assembly anyway though, another good point.
Patrice Brousseau wrote:My 1215 had First a similar problem: there was a point of resistance when starting in manual mode (and it's still there but normal as DualCan told me). The auto function was unable to drop the arm past this same point of resistance.

It was page twelve fig.18 in the service manual of your 1218 I think.
Yes! I just saw this examining the manual again, it describes a different problem as the symptom. But that adjustment might be the key, I'll give it a try. It may be a matter of finessing the amount of overlap between the tonearm pin and the angle in the pawl groove.

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Re: Dual 1218 Auto Start Issue

Post by mrow2 » 21 Sep 2018 06:35

If the ball were to have a little dent, scratch or flat spot, this could cause intermittent trouble. A nick in the track would be a point of resistance, but it is more likely a cause of skipping during play for instance. My PDF guide shows how to apply a carnuba type of wax on the bottom of the deck for parts which can slide against the deck surface (remove part, apply wax, buff and polish, reinstall parts). The bottom side of the deck does acquire roughness over time (corrosion I guess, pretty much invisible). These are just things to do and check. Sometimes correcting several possible points of resistance makes the tonearm movement better in auto mode. Try a different steuerpimpel to rule that out.

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Re: Dual 1218 Auto Start Issue

Post by DSJR » 21 Sep 2018 14:14

Apologies if I'm off track again, but the switching on and off should be done between the beginning of a 12" record and the arm-rest.

If the cueing device is mis-set on some of these models, the indexing lever (#242) connected to the size selector and brought up and down by the main lever might be binding on the tonearm linkages underneath. Thumb not #65 (fig 8 and relevant to fig 24) needs very careful setting on ALL Duals thus equipped in my experience. i usually set the cueing device adjustment #225 slightly 'low' to start with, only adjusting this once the other parts are done - it messes with the other settings if set to high first I find.

These settings don't usually drift and it's usually because former owners have been twiddling that these issues occur. I learned by trial and error long before I had access to the manuals or the internet, so I have to admit that getting a 'feel' for them helped a lot once I had the internet.

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Re: Dual 1218 Auto Start Issue

Post by lreneat » 25 Sep 2018 03:54

I have the 1218 Dual. I recall something that was touching under that curved guard. Carefully check under the guard and see if that pitted silver plate is rubbing when in start-up mode. You get a tiny bit of wiggle room adjustment with that curved guard as I recall.You might have to slightly tweak the offending bar item that is interfering with the free movement of the pitted silver plate. I don't have a manual for the 1218 so the parts name(s) and numbers are not in front of me. This problem if like my 1218 should be easy to correct once you find the offending part item(s). It's been a while since I worked on the Dual 1218 project so my memory may be a little fuzzy.

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Re: Dual 1218 Auto Start Issue

Post by mikepick » 25 Sep 2018 14:02

lreneat wrote:I have the 1218 Dual. I recall something that was touching under that curved guard. Carefully check under the guard and see if that pitted silver plate is rubbing when in start-up mode. You get a tiny bit of wiggle room adjustment with that curved guard as I recall.You might have to slightly tweak the offending bar item that is interfering with the free movement of the pitted silver plate. I don't have a manual for the 1218 so the parts name(s) and numbers are not in front of me. This problem if like my 1218 should be easy to correct once you find the offending part item(s). It's been a while since I worked on the Dual 1218 project so my memory may be a little fuzzy.
Thanks for the tip, I had a similar problem with a 1019 (and have seen other posts to that effect) and thought it might be an issue, but couldn't see anything that seemed to hinder movement there. I'll look again when I get back to this one though, it's not easy to see under there.

Currently waiting on a couple of small parts, and then I'll get back to this one again. Probably will clean and reassemble the entire start lever and switch assembly again...

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Re: Dual 1218 Auto Start Issue

Post by lreneat » 25 Sep 2018 18:43

Yes, the area mentioned is rather obscured. If you remove the screws on that curved guard and hold it slightly back while moving the tonearm back and forth, you will know if this area is the problem with the sticking tonearm movement. It's hard to understand why Dual designers felt it necessary to cut some corners so tight in their designs. The female RCA plugs on the underside are another head scratch-er area where it would have been so easy to have given the gap between the R/L female RCA's an extra 1/2 to 3/4 inch space between the two. German engineering and the many foibles there-in. I'm constantly amazed that people here in the USA still buy German, English and french cars. More money than brains is all I have on why so many people do what they do to lighten their pockets. Good cars are often cheaper to buy, cheaper to maintain and last a long time before turning into a money pit.

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Re: Dual 1218 Auto Start Issue

Post by mikepick » 18 Oct 2018 19:52

Just to revisit, I've had a chance to look at this turntable again and in fact have it playing now.

@Ireneat: I took a closer look under the tonearm cover plate (207). I am getting some friction under there, but it's not the cover plate but the Skating Lever (195) that creates slight friction with the very descriptively named Segment Complete (186).

I removed both parts, and I still get the same hang-up on auto-start, so I don't think that is creating the problem, however. (I know I shouldn't mess with the anti-skate, but since I was missing the tension spring that connected the skating lever to the segment complete, I'm pretty sure it's been messed with prior. I took care to not disturb the set screw or the cam washer.)

Anyway, I received a replacement tension spring and so I've reassembled this area and have the turntable playing again. As before, manual start and auto return work fine, but I get the same hang-up on auto-start about halfway between the tonearm rest and the record edge.

I think I need to take apart, clean and reassemble the Switch arm again. At one point I had it moving and springing back very freely. I still think there is something with Latch pawl 243 that is not quite right, either in ease of movement or adjustment.

I'm also waiting for one of Don's replacement steuerpimpels, which should be arriving soon. I'll be curious to see if it makes any difference.

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Re: Dual 1218 Auto Start Issue

Post by dualcan » 18 Oct 2018 22:46

Hi Mike,
Since there is no calibrated anti skate spring (192), you can not do a precise tone arm bearing test as I would suggest to do in the first instance, but if you have a replacement 192 installed, try the test anyways:
Here is the procedure to check both planes:

Vertical test:
1. Set arm for zero tracking force and zero antiskate force.
2. Balance arm perfectly (perhaps without stylus for safety) .
3. * Place arm between platter and rest post, so it can descent. *
4. Drop a stamp on the head (over cartridge).
Arm must descent all the way for the 1200 series, most of the way for 1000 series with tk 12 headshells and at least lower somewhat for 1009, the lower, the better obviously...
If arm moves without hesitation then vertical bearings are ok.
*Note: for the 1219/1229/1229Q, there is a rubber bridge mounted left of and into the rest post, pivoting on a chrome shaft. This rubber bridge can be shifted/removed to enable a proper vertical test.

Horizontal test:
1. Balance arm as before (no stylus-no stamp...)
2. Apply 0.5 anti-skate on any side of the Anti Skate dial under the tone arm.
3. Bring arm towards center of record.
4. Let arm go.
Arm must return all the way back to rest post without hesitation.
If arm moves without hesitation, then horizontal bearings are ok.

Because the unit was worked on and you don't know exactly on what, I would suggest to remove the main lever (212), and the shut off slide (248) (be careful - don't loose parts 246, 7 and 9) for the test.
Now the arm with segment (186) is riding only on the four pin bearings, plus the pull from the A.S. spring 192.
Since 192 is no longer accurate, the .5g is somewhat arbitrary, but still must pull the arm back home with very light amount of AS applied from 66.

If the bearing tests show the bearings to be free, the next step is to refit 246 to 8 and see if there is drag.
With no appreciable drag, the arm transport comes next. You mentioned that the arm returns ok , so we need to check the amount of friction applied to the lower pimple 190 > tonearm.
With a new pimple and the contact area of the main lever sanded (ideally sandblasted) plus a smear of grease on that area, the arm should get enough impetus to move onto record. Check however if the geometry of the main lever (212) was upset. Do you see pliers marks on the item? The sandblasted "paddle" surface which touches the pimple must be perfectly parallel to the flat section which hold the pin that reaches into the cam (143). The pin itself must be 90 degrees to that surface. I tend to place a suspicious levers etc. on the chassis edge and eyeball for "straighness". For the main lever, the paddle would have to be parallel to the chassis in this context.
checking straightness.JPG
Another item to watch is that the auto and cueing lift do not block the arm movement. The amount of cueing lift must be inferior to the amount of lift that the automatic system has. Adjust the arm height as follows.
With power removed start the unit and rotate platter until arm is fully lifted and starting to move over. This is max height and must be below the bottom record of a stack of records ( to clear arm from stack).
This height is adjusted/limited by 55. Now turn down 65 to lower the arm a very small amount At the stylus end that would mean a drop somewhere around a few millimetres. The exact amount is not too critical, it just needs to lower. Check at the same time if that barrel 65 has a crack in it. That is fairly often the case and prevents that adjustable free play from staying put.
The cue system must also not impede so adjust 225 to also stay below the last arm height position.
The arm should now be free from all encumbrances.
Check now for the main switch lever(252) / pawl (243) clearance (0.3mm) towards riveted square block as shown in Fig 18.
This clearance is adjusted via 213, but don't adjust arbitrarily....
The 1218 is a precision unit which will require precise tolerances to be met in order to function properly.
Unfortunately, the AS spring can not be set properly without the use of precision tooling:
1019 152 CJ no anti skate.JPG
The 1019 shown, has no antiskate and shows a maximum skating pull of 200+ mG .
That skating force is cancelled by adjusting the length of 192 by rotating the half moon 194 all the while re-reading the applied counter force on the skate meter, until the meter reads zero/ central position.
Hopefully the half moon is still attached to the AS spring with the red or blue seal....

There also seems to be a discussion of the RCA sockets used on most Dual turntables. These sockets were used at a time when the plugs did not have the enormous coverings with fancy logos printed thereupon, none of which have a bearing on the plugs performance. It is interesting to note that the world's largest turntable manufacturer at the time, BSR, used a socket with even tighter spacings:
DSC00024.JPG
Dual Spacing of socket
DSC00025.JPG
BSR socket
At the time all these units where made, there were no "monster cables" et all with a need for these bloated covers whlich still are not necessary today..
I am at a loss though to comprehend the linkage of German, British and French car makes to Dual products. Do these cars have inferior technology / manufacturing to Japanese or US brand of cars?
If it is however referencing the precision required in both products, that would be a plus in my view. Precision Makes the Difference after all was the slogan on Dual packaging at the time. It is also the reason we can get these units to perform flawlessly today- with a bit of proper attention and precise service applied.
Regards,
k

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Re: Dual 1218 Auto Start Issue

Post by mikepick » 19 Oct 2018 15:38

Thank you Klaus, for the detailed and informative reply!

I sourced a replacement spring from an online site, but unfortunately I do not have the half-moon washer, both the spring and the washer were missing. I have instead used a hole-punch to make a small cardboard disc with a slit, and mounted the spring that way. So the anti-skate is not going to be accurate, but that's ok for now.

I had a chance last night to preform the bearing tests, the vertical test passed fine, a stamp-like piece of paper will drop the tonearm down to the bottom limit, and removing it allows the tonearm to slowly rise up to balance.

With the anti-skate spring installed, the first horizontal test passed as well, the tonearm swings back smoothly towards the rest with 0.5 set on the dial. However, the catch it that it stops just above the start/stop switch lever, which is also about where it hangs up on auto-start.

I will try the other tests soon when I get a moment.

I have tried to set the tonearm height as outlined in the manual, although the instruction is not entirely clear. I set the lower limit to ~2mm above the start switch and the upper limit to allow a little play between barrel 65 and 55, as I understood it.

I confess I don't quite understand the clearance in figure 18, as in exactly where to measure the 0.3mm.

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