Dual 621 turntable fix

[david correia]

I got a mint Dual 621 turntable with a Grado cartridge that sounds fine.
The tone arm is supposed to be fully automatic. But it no longer moves
over to the beginning of the record when starting it, nor does it move
back to the right when it lifts at the end of a record. It will just go
up and down. It plays as a manual TT, but I want it fully automatic
again.

How much of a pita is this to fix??

David Correia
www.Celebrationsound.com

[Fred]

"david correia" <noe...@comcast.net> wrote in message news:noemail-EE1616...@forte.easynews.com...

If it's like most other Duals, there's a pin coming down from the tone arm that
moves the arm when a platform comes up underneath it and moves sideways,
moving the pin and therefore the arm. There is a little rubber cup on the bottom
of that pin that wears out, and then the platform doesn't put enough pressure on
the pin to make it move with the platform. You'll have to find or make some kind
of a substitute for that cup as Dual is gone and replacements are unobtanium.
Playing with different lubricants and amounts of lube for the upper side of the
platform can also yield results. There needs to be some lube or the rubber cup
will wear out in short order, but if it's too slippery the arm won't move. There
may also be a way to adjust the height of the platform when in the up position -
too low and the arm won't move for lack of pressure on the pin; too high and it
jams the pin and the arm won't move. Duals are finicky. Very finicky.

HTH,

Fred

[Reinhard Zwirner]

david correia schrieb:

Maybe you can find something helpful here:

<http://wegavision.pytalhost.com/dual.html>

("Anleitung" = user manual, "Service" = service manual)

Unfortunately, the service manual for just the 621 isn't provided, but I
think it's highly propable to find the manual for a comparable type.

HTH

Reinhard

[Scott Dorsey]

It's probably not anywhere near as bad as the older idler-drive duals where
everything was mechanical. They were just a horrible nightmare. The direct
drive ones aren't so bad; I would first check the contacts and make sure the
control board knows where the arm is. Get the service manual, they are out
there!

Note that these do have audible cogging and some arm issues; Paul Stamler's
putty trick might help.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[PStamler]

On Jan 18, 1:43 pm, klu...@panix.com (Scott Dorsey) wrote:

> Note that these do have audible cogging and some arm issues; Paul Stamler's
> putty trick might help.

With the arm, not the cogging!

For those who haven't encountered it, the putty trick is to wrap a
thin donut of Mortite, 3M Strip-Calk, or plumber's stainless putty
around the tonearm's shaft. If you do one halfway down the shaft and
another 1/3 of the way from the headshell to the pivot, it helps damp
down nasty resonances. You don't need much putty; if you make the
donut from a piece of unstretched Mortite (about 4mm in diameter)
then, once it's on the arm, flatten it out, you'll be fine. Of course,
the added weight will mean you need to reset the tracking force.

This won't be necessary on a really good tonearm, but on a less
stellar one it can help a lot with damping nasty resonances.

Peace,
Paul

[William Sommerwerck]

> ...the putty trick is to wrap a thin donut of Mortite, 3M

> Strip-Calk, or plumber's stainless putty around the
> tonearm's shaft.

Better make sure it can't fall off while the record's playing...

[Harry Lavo]

"Scott Dorsey" <klu...@panix.com> wrote in message
news:ih4qhc$amd$1...@panix2.panix.com...

Actually, if you like the TT but don't want to bother with the fix, look for
a 701 or a 601. The 701, Dual's first and flagship Direct Drive, had a
massive platter that overcame cogging, and a better, extra-long tonearm.
The 601 featured moderately-heavy platter and a belt drive, and if
well-mainained is an excellent turntable. Both are semi-automatic
turntables and therefore are simpler than automatic Duals. However, be
forewarned that almost all Duals will need some attention to their
auto-mechanisms sometimes during their lifetime.

[Scott Dorsey]

Harry Lavo <hl...@hotmail.com> wrote:
>Actually, if you like the TT but don't want to bother with the fix, look for
>a 701 or a 601. The 701, Dual's first and flagship Direct Drive, had a
>massive platter that overcame cogging, and a better, extra-long tonearm.
>The 601 featured moderately-heavy platter and a belt drive, and if
>well-mainained is an excellent turntable. Both are semi-automatic
>turntables and therefore are simpler than automatic Duals. However, be
>forewarned that almost all Duals will need some attention to their
>auto-mechanisms sometimes during their lifetime.

Attention that will probably involve an incinerator or trash compactor....

[PStamler]

On Jan 18, 3:36 pm, "William Sommerwerck" <grizzledgee...@comcast.net>
wrote:

As long as it's a closed ring with the ends firmly joined together,
and the ring is pressed firmly against the shaft and flattened out, it
won't fall off. At least, the ones I've put on never have, and one of
them's been in place for 15 years.

If you're really paranoid put the gap at the bottom of the ring; then
you'll have some help from gravity. But you won't need it.

Peace,
Paul

[kbos...@gmail.com]

Hi David, did you have any luck in fixing this... coz I have a same problem.
Unfortunately the Service Manual that I found on the net is in German.

Kres

[geoff]

Google Translate ? Good it is very.

;- )

geoff

[kbos...@gmail.com]

Dana subota, 15. siječnja 2011. u 00:12:52 UTC+1, korisnik david correia napisao je:

LOL, no! It's just my broken English :)

Kres

[Chuck]

On Thu, 7 Feb 2019 13:51:09 -0800 (PST), kbos...@gmail.com wrote:

There is a plate that moves back and forth under the arm assembly. A
pin with a rubber boot presses against the plate. That boot can wear
out. Back in the day, I repaired thousands of Duals but I have no idea
where you could obtain the boot today. If the boot is still there you
could try cleaning the bottom of it and the top of the sliding plate.
Put a thin layer of GC Phonolube on the plate and let it cycle for
awhile. If you are lucky, it will begin working again.

[kbos...@gmail.com]

Chuck,
I posted one picture on my facebook page (coz I didnt find way to post it directly here), here is the link...
https://www.facebook.com/photo.php?fbid=10211046470556037&set=a.1329975387803&type=3&theater
Can you tell me is this pin marked with number 206 pin you are talking about?
Maybe there is a way to make such a rubber cap, or something else that would work as well.
Anyhow thank you for your answer.

[kbos...@gmail.com]

Dana subota, 15. siječnja 2011. u 00:12:52 UTC+1, korisnik david correia napisao je:

Or maybe after 40 years is time for the new turntable :)

[Scott Dorsey]

<kbos...@gmail.com> wrote:
>
>Hi David, did you have any luck in fixing this... coz I have a same proble=
>m.=20

>Unfortunately the Service Manual that I found on the net is in German.

These things are horrible abominations that need to die, but they are really
not difficult to work on if you think about the mechanics. Everything is
controlled by the big yellow brain cam and if something is moving or not moving
it is likely because whatever the brain cam is supposed to be shifting is not
moving.

What is useful about the service manual are the tear-down diagrams, the text
is really not useful anyway. Turn the thing on the side and watch what
happens as you set the lever into play... see how the brain cam turns and
what it's moving. It may not be in the right position or one of the gadgets
that follows it may be cracked or broken.

But really, the whole idea of stacking records and autochanging is a bad
one if you care about your records.

[Chuck]

On Fri, 8 Feb 2019 11:57:26 -0800 (PST), kbos...@gmail.com wrote:

Yes, It is the cap on 206 and one cleans and lubes the top of the
right end of 183. If the cap is missing, something else might work. I
worked for one of the largest U.S. Dual dealers so I had a ready
source of parts so I never had to experiment. Good luck.

[this]@ri.t-com.hr Edi Zubovic 1]

On Fri, 08 Feb 2019 11:05:34 -0600, Chuck <c...@dejanews.net> wrote:

>>Hi David, did you have any luck in fixing this... coz I have a same problem.
>>Unfortunately the Service Manual that I found on the net is in German.
>>
>>Kres
>There is a plate that moves back and forth under the arm assembly. A
>pin with a rubber boot presses against the plate. That boot can wear
>out. Back in the day, I repaired thousands of Duals but I have no idea
>where you could obtain the boot today. If the boot is still there you
>could try cleaning the bottom of it and the top of the sliding plate.
>Put a thin layer of GC Phonolube on the plate and let it cycle for
>awhile. If you are lucky, it will begin working again.

Hello R.A.P. after a long long time, Hello Scott and other members.

-- Yes this is a known problem with Dual changers, go to German Ebay
and search for "Dual Steuerpimpel".

Best,

Edi Zubovic, Crikvenica, Croatia

[kbos...@gmail.com]

Thx Edi :)
There tones of it, all kind... for every Dual model.
Tell me Edi do you have maybe repair shop?

[this]@ri.t-com.hr Edi Zubovic]

--Well not an "official" one, but I do have a well equipped shop.

[this]@ri.t-com.hr Edi Zubovic]

--Now I've been thinking about this a bit, if the turtable was mint
there shouldn't be any problem with the "Steuerpimpel" unless it is
cracked due to hardened plastic over the time. I doubt that.

If I faintly remember, Dual changers may get out of synch after
transport.

Try this,--

keeping the start lever in "on" position, try rotating the platter by
hand a whole cycle and see if it changes something -- don't try too
hard.

[kbos...@gmail.com]

Edi,
da li bi se Vi privatili servisiranja mog gramofona, uz naravno neku razumnu nadoknadu.
Vidim da ste stručnjak a ja sam po tom pitanju totalni diletant.
Gramofon je kod mene već skoro 40 godina i nikad nije bio otvaran do prije neki dan. Trebalo bi ga generalno podmazat i sredit to automatsko startanje i gašenje.
Jedino što je novo na njemu je igla. Zvučnica isto nije nikada dirana al mi se čini da je ok.
Ako ste zainteresirani slobodno me nazovite na
091 940 8975.
Živim u Gorskom kotaru a radim na Urinju u rafineriji tako da mi nije problem doći do Crikvenice.
Pozdrav
Krešimir Bosnar.
P.S.
Ta plastična kapica se raspala

[this]@ri.t-com.hr Edi Zubovic]

OK, it seems indeed that the cap is gone. Well then, I'll PM you...

[Chuck]

On Sun, 10 Feb 2019 15:25:48 +0100, Edi Zubovic <edi.zubovic[rem
this]@ri.t-com.hr>1 wrote:

>Dual Steuerpimpel

Thanks for this information. If I can find a source for the idlers, I
might start repairing these again.

[this]@ri.t-com.hr Edi Zubovic]

--You're wellcome. Idler wheels are scarce. I don't know who makes the
new ones or refurbishes their old rubber. Here or there they appear
either as used or (rarely) NOS at Ebay. Try Dual Treibrad at German
Ebay. Usually they aren't so problematic unless they are very worn
out or they somehow remained pressed against drive shaft.

Oh yes! Antiskating wheels can be easily found as well. These can be
often found cracked.

[Scott Dorsey]

Edi Zubovic <edi.zubovic[rem this]@ri.t-com.hr> wrote:
>
>--Now I've been thinking about this a bit, if the turtable was mint
>there shouldn't be any problem with the "Steuerpimpel" unless it is
>cracked due to hardened plastic over the time. I doubt that.
>
>If I faintly remember, Dual changers may get out of synch after
>transport.

They get out of synch ALL THE TIME. You don't need to transport them,
you can just flip the levers in the wrong directions while it's doing
something and get it out of synch.

This is why I say... look at the brain cam and see that it's turning
and watch what it's moving around. If it's not moving the right things
either the things are broken or they aren't in the right position or
the cam isn't in the right position.

>keeping the start lever in "on" position, try rotating the platter by
>hand a whole cycle and see if it changes something -- don't try too
>hard.

This is a useful thing to do, but watch underneath while you're doing it.

[Scott Dorsey]

The last I saw, PRB still had idlers available for these things. If not,
Dave Dintenfass will occasionally put together a group buy on the Ampex
Mailing List to have new pinch rollers fabbed up... whoever he has doing
that can probably make you Dual idlers too.

The nice thing about the Dual idlers is that there are only a couple
different sizes for all their models.

But really.... the whole autochanger idea is so wrong...

[kbos...@gmail.com]

I just have to correct you a bit Scott. The problem has got nothing with autochanger, Dual 621 doesn't even has this option. Problem is with automatic start so you don't have to manually put the needle on the record. And second, the needle won't get on starting position once it reach the end section of the record.
But I agree with you that autochanger is not friendly to records ;)

[Trevor]

So is the idea of idler wheels on manual turntables. :-(

[Chuck]

Scott,
I agree with you more than 99% of the time, but the turntables that
got out of sync and often self destructed were PEs not the 12xx or 6xx
series Duals.