1245 tonearm setdown point movement

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analoged
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1245 tonearm setdown point movement

Post by analoged » 02 Dec 2019 17:12

I think that I have seen this issue referred to here in the forum but I can't find the relevant posting.
In auto start:
The arm lifts 7mm up from post as specified in S.manual.The arm moves over to the record,stops lateral movement,and just before dropping,arm moves 2 or 3mm inward then drops.
This is the first time encountering this problem for me.
Does anyone have knowledge of how to rectify this situation.I sure would appreciate the help.

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Re: 1245 tonearm setdown point movement

Post by DSJR » 02 Dec 2019 18:22

Possible silly question, but I'll ask it anyway...

When the auto mech lifts the arm, is there a smidge of free vertical movement before the arm its the max height stopper - #78 in the exploded parts list (adjust with thumb nut #52 pictured in fig 13 in the service manual on top of the lifter #56)

I only suggest this as if the arm is lifted too high and 'jams' on the height restrictor, all manner of things happen, such as little to no lateral arm movement under auto control to the linkages underneath not freeing the arm up when they should. To start with, I'd suggest setting the cueing height slightly low first to get the auto side working properly (#42), and only setting this correctly once this is done. Doing it the other way round totally messes the adjustments up as the cueing height assembly is also the basic pivot on which the lever #204 operates. Easier to see than for me to describe, sorry.

What's the pimpel like? there should be 'some' gadus (alvania) on the paddle end of the main lever, but too much can cause the main lever not to fully release from the pimpel. It seems a terrible compromise, but get it right and it works flawlessly for decades.

Hope the above helps rather than hinders. All Duals from the 1007 onwards work the auto mechanism in pretty much the same way, but the introduction of the later cueing lift arrangements did need slightly different set up procedures and Dual simplified the details further in later models, making them even quieter in use too I remember.

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Re: 1245 tonearm setdown point movement

Post by analoged » 03 Dec 2019 00:42

Got it,after using several China -pimples with good results,this deck just would not cooperate with one,I even squared the rounded end off and that did nothing.I replaced it with a factory 777 one and problem is gone.It's funny,most times I use the C-Ps they are no problem at all.But ,I once did a 601 and it didn't work with the stock 777 part untill I shimmed it out a tiny bit.
DSJR,when I service one of these,it's just a hobby not a job ,I always set the cue height screw all the way out untill it contacts the E ring.Then I set the lift spec up off the rest as per service manual then cue height.
Thanks for the suggestions.

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Re: 1245 tonearm setdown point movement

Post by DSJR » 03 Dec 2019 06:58

Some pimpels are too long for the sprung? studs they sit on and my 601 needed its replacement pimpel to be slightly trimmed so the stud could retract slightly under its spring loading. Mrow2 (Don) here does suitable ones and I think there are German suppliers too. May be worth looking on the Dualcan site for suggestions (I haven't lately) as some pimpel types work better with some decks over others (not as much a minefield as I suggest, but there are old threads here going back a few years).

Anyway, glad you have it sorted now.

P.S. You know, Dual in their current form do still make auto decks and I seem to think they continue to use the main lever plus pimpel arrangement as in these 'classic' models. Not sure how easy it is to contact them, but I wonder if the current pimpels they use are the same as the older types?

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Re: 1245 tonearm setdown point movement

Post by mrow2 » 03 Dec 2019 23:02

The Pimpel-on-the-pin does seem to retract a bit on many models and therefore I am paying attention to that. I am only aware of about "2½" conditions which might cause the sideways set-down jump, besides an obviously defective or improperly conceived steuerpimpel: Too much (Gadus) Alvania on the Main Control Lever can cause it to continue to stick and pull the pimpel as it stretches the grease to the point of separation (I think DSJR has that correct description nailed); and a pimpel which is not mounted far enough onto the pin so that about 1mm of pad thickness (or height of the pad to the end of the sprung pin) exists. As a side note that second point, the pad surface should be level with the Main Control Lever and not visibly higher on one edge than another. That condition (and especially with too much grease on the surface as well) might conceivably cause the arm to move sideways as the main lever pulls away from the positioning operation. At present I'm allowing a little over 4mm in length (height) for a pimpel. It's been that way for quite some time. But certainly a table can have other issues going on as well, which can interfere with proper tonearm operation.

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