601 tonearm travel issue

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analoged
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601 tonearm travel issue

Post by analoged » 23 Feb 2019 00:35

Hello,
I have a 601 whose tonearm (balanced ,no antiskate) gets about 7.5 cm from spindle and meets resistance.This leads to last track of record skipping or sounding horrible.When it rarely makes it to the lead out groove the arm is wrenched backward as it raises with disastrous noises.You can actually see the arm going up at an angle outwards.
I sent this to a supposed "expert " and was told it was a bearing adjusted to tight,WRONG.It is still doing it.At the time I asked how a tight bearing only affects the last few inches of travel,no response...
Before I tear into it,what should I look for.I am thinking it is the shut off lever but haven't looked yet.
help PLEASE.
Ed

Spinner45
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Re: 601 tonearm travel issue

Post by Spinner45 » 23 Feb 2019 01:56

Something like the automatic trip linkage is likely bent or mis-adjusted.
This happens due to carelessness or in-experience in servicing.
The trip linkage and its associated parts are VERY delicate.

mrow2
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Re: 601 tonearm travel issue

Post by mrow2 » 23 Feb 2019 02:29

Yes, You should examine the entire linkage of the tonearm and with it raised observe how it travels and what is happening underneath. Check the tiny cables from the tonearm to be sure they are not finding some resistance somewhere.

analoged
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Re: 601 tonearm travel issue

Post by analoged » 23 Feb 2019 14:53

So,the shut-off lever 170, and friction plate 171,were bent pretty badly.I straightened them as best i could and put them back on the cam.But they flopped around so loose on their axle,I thought I didn't do a good job straightening them.I looked closely at this and compared it to a known good cam and saw that the tiny axle was sticking out further on the problem girl.Sure enough,the axle was able to be pushed back into the cam.So,whatever trauma that occurred to bend these levers must have loosened the axle.
I could try glue to keep the tiny axle from moving,but I don't trust this repair so I will use the cam from my parts table.I don't want issues down the road. I'll get back to this thread after getting this all back together.I'll let you know outcome.
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DSJR
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Re: 601 tonearm travel issue

Post by DSJR » 23 Feb 2019 15:24

So, has someone been at this deck then do you think?

I'd have thought a pin-prick of superglue in the cam-hole would be fine to firmly attach the 'axle' of the trip pawls (169 and 171) to the cam, just let it dry thoroughly and only use a pin prick, so it doesn't overflow and impede free movement. organdonorparts did have 601 parts not listed and because I don't think this cam is shared with other decks (I haven't checked I admit), it'd be worth getting this one sorted carefully. Klaus and I differ here, but since the 601 cannot do 78rpm, I feel that free moving un-lubricated trip pawls should be fine as the cam won't ever move quickly enough. As many people would inavertantly ladle lubricants on with a trowel, I feel justified in the 'keep it dry' suggestion and my own Duals don't seem to have lubricant on these parts from new, although I could be wrong. I suspect the tiniest little dab on the sharp end of a pin is where Klaus may be at here ;)

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Re: 601 tonearm travel issue

Post by analoged » 23 Feb 2019 16:23

Yes,there are signs of some hamfist working on this previously.But I bought this from an individual that is known for his repairing of Dual tables.And I sent it back because of the tonearm issue that was not resolved .Most of the shafts that screw into the chassis have their screwdriver slots messed up by the wrong fitting drivers.I found the wrong spring in the cueing lift adjustment piece.It sported a fake pimple/guide and the control arm had a piece of friction tape where the pimple/guide rides.This table also has rumble the likes of which I have never heard from a 601.I will go through this whole table now because I don't think it received a proper service before I got it.
I have lubed the cams on 6 601s using Dualcan's guidance and all have performed perfectly.
Another case of,if you want it done right,do it yourself...

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Re: 601 tonearm travel issue

Post by Spinner45 » 23 Feb 2019 16:32

analoged wrote:
23 Feb 2019 16:23
Yes,there are signs of some hamfist working on this previously.But I bought this from an individual that is known for his repairing of Dual tables.And I sent it back because of the tonearm issue that was not resolved .Most of the shafts that screw into the chassis have their screwdriver slots messed up by the wrong fitting drivers.I found the wrong spring in the cueing lift adjustment piece.It sported a fake pimple/guide and the control arm had a piece of friction tape where the pimple/guide rides.This table also has rumble the likes of which I have never heard from a 601.I will go through this whole table now because I don't think it received a proper service before I got it.
Another case of,if you want it done right,do it yourself...
Sadly, there are many "ham fisted" rocket scientists out there, butchering up all kinds of stuff.
I suggest that these types should have gone into another field of service..... perhaps doing open heart surgery instead, or fine Swiss watch repair. :shock:

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Re: 601 tonearm travel issue

Post by analoged » 24 Feb 2019 00:07

Ok ,got everything back together.It cycles way quieter than before,but the original issue is still apparent but to a lesser extent.It looks like 262 shut off bar was tweaked when the catastrophy with the cam happened.It didn't look bent,but I will check closer for binding at the arm segment axle and the opposite end that contacts the shut off lever on cam.The resistance starts just as the triangulated end approaches the cam shut off lever.

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Re: 601 tonearm travel issue

Post by mrow2 » 24 Feb 2019 18:50

It seems like you are definitely in the right area. But I see shut-off lever as 161 and the ball right next to it in the explosion view. Shutoff lever 170 is critical too, but I think it could be worked on if there was not a replacement. I do know that it's critical that these be perfect or very near-perfect. Didn't see 262.

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Re: 601 tonearm travel issue

Post by analoged » 24 Feb 2019 21:59

OK,here is where I am at:
I disconnected the the shut off bar 262,I thought this would be the culprit,but it was not.
One thing left(I thought/hoped) the antiskate spring.Removed it tested arm,nope,still doesn't like getting within 7.5 cm from spindle center.
The wiring is not the issue.
So,I tried loosening the vertical bearing and still ,no dice.
I think the only thing left are the arm parts (37,66 and their bearings) that allow horizontal movement??Maybe something is bent or a bearing is at fault.
I think I'll take a break from this for awhile before changing out the whole tonearm assembly.I will get to the cause of this.Getting tired of playing with it for now...

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Re: 601 tonearm travel issue

Post by analoged » 26 Feb 2019 22:11

A little more progress:
Removed tonearm,all appears good with it and associated bearings/parts,but the cueing cylinder was loose.I thought the screw was stripped out.Removed it,found the cueing piston almost unmoveable because of excess/dried siliconoil.So I started cleaning it up and found the cylinder loose where it is crimped to the flat plate/mount and the little mounting plate is bent also,yikes.So into my spare parts again for a lift I had serviced and ready to go.I am glad I have spare parts.
Hopefully when I get this back together I will have kicked these multiple problems in the arse.
I can't believe I payed what I did for this battered old girl.But I do enjoy working on these in the winter and setting them straight.And I did get a nice new base and dust cover with it.; )
I'll keep you all posted on my progress.

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Re: 601 tonearm travel issue

Post by analoged » 02 Mar 2019 00:03

My original fear has come true.The screw hole that holds the cueing cylinder(213 lift plate) is stripped.But,I was able to catch the lower threads with a 2mm longer screw.The called for 3mm long screw barely clears(maybe 2 threads) the thickness of the lift plate.
So,on with the assembly....

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Re: 601 tonearm travel issue

Post by analoged » 02 Mar 2019 02:13

Success,
I now have a 601 whose tonearm travels unimpeded the entire arc of travel.It was the lift plate(cueing cylinder) that was seriously fubar.
Thanks for all your help.
My persistence payed off.
Time for an adult beverage.
Cheers !

2002afan
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Re: 601 tonearm travel issue

Post by 2002afan » 02 Mar 2019 05:04

analoged wrote:
02 Mar 2019 02:13
Success,
I now have a 601 whose tonearm travels unimpeded the entire arc of travel.It was the lift plate(cueing cylinder) that was seriously fubar.
Thanks for all your help.
My persistence payed off.
Time for an adult beverage.
Cheers !
Analoged, Congrats for getting it back operational. 8)
You earned it. =D>
Cheers,
WillO

T68
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Re: 601 tonearm travel issue

Post by T68 » 02 Mar 2019 10:14

Good work and troubleshooting, analoged!
I'll keep this in mind if I get problems like this on my 601.
Hope it behaves better for you now to enjoy. It's a great deck when running properly.

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