Sota Cosmos: to restore, or?

Hello fellow DIYs
Recently I made a rather bad acquisition. I always wanted a Sota Cosmos, and this looked like a decent table. Turned out not so much. It’s an early unit, and would cost too much (for me) to upgrade it to current status by Sota. So my choices are: 1. Selling it as is; 2. Parting it out. 3. Trying to fix it, and to do this I need technical help, because not much info is available. It has three major problems:
1. Speed inconsistency, which can be fixed in two ways: rebuilding motor-associated electronics and hoping it will work, or buying new Eclipse motor/controller from Sota, $750;
2. Lip on platter does not seem to hold the vacuum too well. “Seem”, because when I do recommended by Sota test - sucking on the vacuum line - record does get sucked to platter and I don’t feel any leaks. This has to be done by Sota, another $500;
3. Vacuum pump is acting strange, and I actually don’t know if it’s because the lip is not sealing, our electronics are at fault, or the pump is not pulling enough vacuum. I know that pump is supposed to pull maximum at the start, and then slow down. Well mine doesn’t do it. It stays on all the time. The records seem to stick to platter pretty well, afterI help them by tapping my finger on the edge to overcome that stiff lip. If I knock on record’s surface I can tell it’s snug against the platter. I news help with electronics, since no schematic is available for the vacuum control. I could just stupidly replace everything, but the pump itself I couldn’t find. The fittings at the pump are rather ugly and not sealing right.
I have to say that when it’s speed instability is at its minimum, this things sounds really great. But if I can’t solve the problems, I will have to get rid of it one way or another. I have a ton of pictures of some guru is willing to help me. Thanks in advance.
 
If the pump is holding down the record but still running continuously at full speed then you have a leak.
But you also say it seems to be firmly stuck to the platter then there is a leak somewhere between the pump and platter .


If the speed inconsistency is variable then you have a bad connection in that part of the circuit .


It would help if a circuit diagram was available but having seen the full price for one of them I can see the allure of buying one cheaply , its a top end deck ( or near it ) and in good working order worth 1000,s of $$$$ .


Your problem isn't an instant fix as you have electronic and mechanical problems in a very expensive deck .


It isn't the only make with a vacuum deck the UK had one long ago but it adds to the complications.


I could repair your pump and or problem with the lip but we are 1000,s of miles apart and most reasonable electronic circuits can be slowly traced out for a fault but that takes time , doing it virtually takes much longer as I don't have it in front of me nor have I a circuit diagram .
 
If the pump is holding down the record but still running continuously at full speed then you have a leak.
But you also say it seems to be firmly stuck to the platter then there is a leak somewhere between the pump and platter .


If the speed inconsistency is variable then you have a bad connection in that part of the circuit .


It would help if a circuit diagram was available but having seen the full price for one of them I can see the allure of buying one cheaply , its a top end deck ( or near it ) and in good working order worth 1000,s of $$$$ .


Your problem isn't an instant fix as you have electronic and mechanical problems in a very expensive deck .


It isn't the only make with a vacuum deck the UK had one long ago but it adds to the complications.


I could repair your pump and or problem with the lip but we are 1000,s of miles apart and most reasonable electronic circuits can be slowly traced out for a fault but that takes time , doing it virtually takes much longer as I don't have it in front of me nor have I a circuit diagram .

Thank you. The more I think about it the more I incline to selling it as it’s to somebody who is willing to try. I can try to rebuild the pump with new rubber parts, I think I have located a kit on ebay. Fittings will have to be reworked. Circuit diagram is not available. There is a vacuum-sensing switch on OCB. I don’t know how to fix the lip, as the only fix toted is to send player to Sota, who will unflue the topmost 5 mm acrylic mat and install it back with a new lip. Speed problems are the common problem of the original Papst motor. That’s the reason they recommend going with the new set up. In any case, you are too far ))) Thank you for the input.
 
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If you have 2 green 10nf caps on yours , replace these as they caused similiar issues with higher voltage ones . Might as well replace the other cap and the 555 timer while your in there. Cheap enough , same goes for the motor board components.

The style of the rubber lip is rather short on height and on mine , I tap around the record edge as it rotates on badly warped ones to get it to seal. I,ll assume you know about the suction strength knob

Whether you keep it or not you should pull the platter off and run your finger nail across the spindle to check for wear. I would sell it if you feel any ridges

SOTA charges are very steep IMO but for a suspension table it works and you shouldn’t have any speed issues if you change out the small number of components

Regards
David
 
Thank you David. My electronics are completely different. I will post pictures. I have replaced three out of four electrolytics on ps/vacuum board, getting the last one tomorrow. Also getting two tiny caps for the motor board. My lip requires “the finger-tap treatment” for all records. I would pull the platter out to examine the bearing, but it has a vacuum line running into it, and I’m a bit worried as I don’t know the design. Pls see pictures. Cismos of 1989 vintage was pretty far ahead of regular Sotas, and was more like a rather modern Nova. Thank you.
 

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Your shaft will look similiar and no issues with the vacuum system, very simple affair . The vacuum connection is on the bottom of this , yours on the side.
I like the rigid aluminum coupling system

Looks like you need to get under the platter and remove those Allen’s and the platter will pull off
Check wear and replace the oil.
They use Tuffoil the last time I checked with them

I never seen these pics of the Cosmos and very different , yes
 
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Do what Avwerk says and check the platter shaft and bearing. I've seen many speed issues due to bearing being worn and no longer round. Do this step first before doing any/all electronic adjustments.

Belt may be slipping if it hasn't been replaced and also causing speed issues.

After the above two steps then dive into the electronics. The new Cosmos is entirely different, as you're aware, and there is not an upgrade kit (yet) that I'm aware of for these early Cosmos.

We have quite a few of these early cosmos in the trade in pile, because with the total cost of updating people have chosen to just get into a new Nova, or Sapphire with much better speed control of our (not 31 yr old) current electronics.
 
Will do. I guess it does belong in a pile of garbage... Just like my brain, for not thinking when I was buying it. But I have to say, it sounds great. In fact, it’s probably the best table I’ve had...
As far as new electronics goes, I can easily adapt the Eclipse motor/controller to it, albeit at a cost of $750. So - that, plus new lip/bushings, vacuum pump not working right etc - forget it.
In addition to three Allen bolts holding the platter, there’s also a huge countersunk bolt on the bottom, right under the spindle. I guess it has to come out too.
Thank you.
 
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Why give up before you even start?

I have repared a pair of Luxman with vacuum plates because they did not hold vacuum. My tip is to first go over the entire vacuum system, replace the hoses, check the switch that closes when the vacuum reaches its optimum, look at all the seals, it is enough that a single one has dried out or has become worn for nothing to work. The Luxman I have made has cost about $ 20. I have been looking closely at the pictures there is a trimpot for the vacuum it may need to be adjusted. But start by replacing and fixing the vacuum system.

I can sound a little harsh but everything can be fixed without buying expensive parts I have done it often when others claim that it is not possible.
 
Thank you K. A. B.
I have started doing that: I found some new old stock rubber replacement parts for the pump, but they are nearly as old as the pump itself, so I’m not sure their condition is any better; I found nearly exact pumps on Ebay, but they are 110v instated off 12v like the original, and require mods to vacuum connections; i have to come up with the way to re-do existing pump connections as they are horrible; I didn’t get to the vacuum switch yet, these are available new I think still; the biggest problem is the lip. I don’t know where to get a replacement, except from Sota, or even how to unglue the top mat to remove it. Sota charges $500 to replace the lip. I don’t think the existing lip can be revived.
 
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Why give up before you even start?

I have repared a pair of Luxman with vacuum plates because they did not hold vacuum. My tip is to first go over the entire vacuum system, replace the hoses, check the switch that closes when the vacuum reaches its optimum, look at all the seals, it is enough that a single one has dried out or has become worn for nothing to work. The Luxman I have made has cost about $ 20. I have been looking closely at the pictures there is a trimpot for the vacuum it may need to be adjusted. But start by replacing and fixing the vacuum system.

I can sound a little harsh but everything can be fixed without buying expensive parts I have done it often when others claim that it is not possible.

Hi. How did you repair the lip? Thx
 
Motor modifications and resistors out of tolerance

So this motor in this Cosmos appears to be moded. I don’t know where these moods where performed. For comparisons are pictures of my motor (with yellow caps and a pulley), and a standard Sapphire motor (with no pulley). In addition, out of 15 resistors more than half is way outside their 1% tolerance. Plot thickens...
 

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Thank you David
Wow! 3 Sotas AND a Versa? If I had the Versa I wouldn’t be looking for anything else.
In the latest Eclipse incarnation Sota moved motor back on plinth, similar bracket to original. I can do it, but I won’t. I can not hear any problems with current set-up, so why bother. If I fail at fixing this motor/electronics, and decide to keep it and get the Eclipse upgrade, I will also mount it in exact same spot. My friend has a CNC machine so if I decide to move it to plinth I can do it too. So far I’m not sure I should keep it.
The problem with the lip is that it has hardened and does not want to “give”, so to speak. It does not want to spread outward and let the record come down to the platter. It actually happens in one specific spot, about 1/8th or the outside circle. So I don’t really know what to do with it. Profile of the lip was wrong to begin with, I agree with you. And when I saw what was inside that vacuum enclosure, I am not impressed at all. The little tiny pump is an exact “Second Nature Whisper 100” or 200 aquarium pump, but it runs on 12v instead of 120. I can not imagine seeing this in a Basis, for example. So I may dump it after all...
 
Sorry I deleted my post after you commented already.

Sounds like your rubber is toast then. You might look for some “L” Shaped window seal and super glue the junction.
Easier said than done however.

As far as the vacuum pump goes , it doesn’t take much vacuum to seal a record and they have been reliable and at least available cheaply
The last thing you want is more vacuum capability, you want just enough to hold it down and no more .

When I bought my Versa it had no pump and I rewired one of the sotas vacuum box to run the Versa,s seal.
Works perfectly with the thinner and more flexible design.