Dual 505-2 tonearm balancing issue

[joostdemoor]

Hi all,

My first post here. I've tried to make sure my question wasn't already addressed here previously...

I'm trying to balance the tonearm of my 505-2. I know the procedure from youtube clips etc. The problem is that the vertical bearing seems a bit sticky, and therefore the arm stays level, even though I move the balancing weight back or forth (unless I make extreme changes), and the arm equally stays in place when I point it up or down. I've already tried to resolve this by applying some contact cleaner (simply spraying it around the vertical pivots), but no success.

In general, the table has no issues with tracking and plays well, and the vertical movement of the arm feels smooth - just not smooth enough for balancing. But I worry that without getting the balance perfect I will damage records and stylus (especially since I'm considering upgrading with an OM 20 stylus).

Many thanks for any help!

Joost

 

[stratokaster]

The Dual has a dynamically balanced tonearm, the vertical force is applied by a spring. Make sure to set the VTF dial (on the right-hand side of the pivot) to zero before attempting to balance the tonearm.

 

[joostdemoor]

Thanks stratokaster. I've done that. Like I said, I've followed all the instructions for balancing it. Yet where in youtube clips I see people finely adjusting the counterweight until the arm is perfectly in balance, mine just sticks at whichever level I put it in, and whichever position the counterweight is in (unless it's either completely in or out).

 

[loudnoises]

Do you have a scale?

Are any of your adjustments able to affect the vtf? Especially adjusting the spring wheel.

It sounds like you've been using it, and if the vertical bearings were sticky it would track horribly.

Have you lubed it at all?

 

[joostdemoor]

Thanks for your reply loudnoises. I don't have a scale that is accurate enough, but I realize that would be a useful starting point. However, I also read that even if you get the vtf correct according to a scale, when playing a record, the arm still needs to go up and down depending on the width of the groove, and that the pressure wouldn't be even, due to the stickyness of the vertical bearings (it would be too low in deep grooves, too high in shallow ones).

As for adjustments, I've used the spring wheel (at least I think that's what it is) to put it to 0 for balancing, and then adding the recommended tracking weight (1.25 - 1.75) once I've approximated what I think would be the balancing point if the stickyness wouldn't be an issue.

And yes, I've been using the turntable for about 50-100 hours now since I bought it second hand. It works very well. Tracking is not an issue at all. I'm just worried that the tracking weight will be off since balancing isn't possible through the recommended method due to what seems to be the stickyness of the vertical bearings. This, I'm afraid could affect record and stylus wear, as well as sound quality (but correct me if I'm wrong).

As for lubing, I read on various fora that you're not supposed to lube tonearm bearings, since they are made to run dry. I did apply contact cleaner yesterday (simply spraying it on the area where the bearings are, hoping it would get in, dissolve any gunk, and then whyping it off).

 

[loudnoises]

There are a few tutorials on lubrication, I'm not sure what the recommendation is.

The arm on my 1219 was not very happy, till I did as you describe and cleaned out the bearing. A drop of oil, and discovering that my spring wheel was not accurate to the numbers (1 is 1.5g, it's not linear) and it is almost too free moving.

You definitely should have a scale, it's pretty key on these low tracking weight carts. My arm will track at 3/4g no problem, and I'd be way off without the scale. A cheap digital is very worth the money.

Now is about when one of the actual experts will chime in...

 

[joostdemoor]

Thanks again loudnoises. I'm sure that will be a good place to start. Hopefully some of those 'actual experts' as you call them are willing to add their view on getting that vertical movement back to normal again

 

[lini]

As for lubing, I read on various fora that you're not supposed to lube tonearm bearings, since they are made to run dry.

Yes, Joost, that's correct. So depending on which cleaner you've used, you might have made it worse (if not right from the start, then in the long run, as many types of contact cleaner contain ingredients, which won't dissipate completely and will hence rather cause the bearing to collect more dust over time...).

And regarding the initial cause, maybe someone has tried to adjust the bearing play and has adjusted it a little too tight.

Greetings from Munich!

Manfred / lini

 

[joostdemoor]

Thanks Lini. I applied contact cleaner named "Kontakt 60", bought in the Netherlands. It shouldn't have any lubricants added to it, so hope to be ok on that front, but good to know that I need to be careful.

As for the tightness: do I understand correctly you suggest it's worth trying to untighten the vertical bearings (presumably only a tiny bit)? And if so, do you have any recommendation on how to, or where I can find this?

 

[Jeff449]

You should be able to get the service manual online.
Vinyl Engine should have it.

 

[joostdemoor]

Thanks Jeff. I've looked at the service manual and the owners manual, but both are quite minimal, showing me what's where, but not what I should do. I could probably figure it our, but want to make sure there's nothing I should know on beforehand.

 

[lini]

(...) I applied contact cleaner named "Kontakt 60", bought in the Netherlands. (...)

Oh, oh, that's an aggressive one. You'd best flush that with Kontakt WL (or, if you can't get that, you could also use Kontakt IPA, Tuner 600 or Video 90).

And yes, just a very tiny bit, so it's moving freely, but doesn't become not too loose/wobbly yet. The grub screw with the bearing tip should be on the left/inner side - and I think it also has a counter-nut (just like the one at the top for the lateral motion), so you'd most likely also need a tool for loosening that nut first. If you don't happen to have a suitable "Stirnlochschlüsselsatz" at hand and don't want to improvise, the next best thing would probably be a Knipex 44 21 J01. You really need to be very careful, though.

Greetings from Munich!

Manfred / lini

 

[joostdemoor]

Thanks a lot lini. Very useful. It might take me a few days to get my hands on stuff to flush it out. Hopefully it's not that aggressive that it will do damage in the course of a few days...

 

[joostdemoor]

Oh, oh, that's an aggressive one. You'd best flush that with Kontakt WL (or, if you can't get that, you could also use Kontakt IPA, Tuner 600 or Video 90).

And yes, just a very tiny bit, so it's moving freely, but doesn't become not too loose/wobbly yet. The grub screw with the bearing tip should be on the left/inner side - and I think it also has a counter-nut (just like the one at the top for the lateral motion), so you'd most likely also need a tool for loosening that nut first. If you don't happen to have a suitable "Stirnlochschlüsselsatz" at hand and don't want to improvise, the next best thing would probably be a Knipex 44 21 J01. You really need to be very careful, though.

Greetings from Munich!

Manfred / lini

I didn't have any tools for loosening the counter-nut, so I just tried to see what happened if I loosened the screw you mentioned (part 51 on the manual, I believe). I could turn it easily without having to loosen the counter-nut. I loosened it about 100 degrees, which did free up the vertical movement a bit, but not perfect, and loosening it more had no further effect. So I then tries to see what happened if I'd loosen the opposing screw (part 55) a bit (also about 100 degrees) and that further freed up the vertical movement. I wouldn't say it's still not 100% moving freely, but emough to give me the sense that I could meaningfully balance the arm. Everything works well now, but it already did before. Will now order a stylus force scale to check the result. I'm curious to hear your thoughts on what I did.

In the meantime, I'm anxious to remove the Kontakt 60 as soon as possible. Hopefully I manage to pick up one of the products you mentioned by tomorrow, and the damage done by the Kontact 60 won't be too significant...