Micro Seiki Air Bearing service



Recently my MS SX8000 has been playing a small game with my music, at times it slows down not that much but enough to get those “weird” piano notes.

I was thinking that maybe this is the motor that is showing signs of it age despite the service it had received. Upon closer inspection I notice that the platter did not spin as easy I felt it should, when switching the motor off it maybe slowed down too fast, at least that is what I said to myself. In all honesty this is a subjective measure by all means

Then I recall that sometime back when I was installing and fitting the feet that some oil (maybe ½ teaspoon worth) had leaked from the centre spindle when the TT was turned upside down. This is the small stainless steel axis in the middle. At the time I did not pay that much attention to this matter. A fellow SX8000 friend who hides himself by the Bavarian hills and his turntables had experienced the same thing, we did not worry.

However in the light of the above I was wondering if this had any connection. Service and information in this domain are somewhat hard to come by.

So my question was why oil, why so much ? I set to find out and took the platter off the TT. Then I noted that when turning the small spindle with my finger it was not “super”smooth, okay but not "Japan maniac level".

With my limited technical knowledge I kind of figured that I would have incorporated an oil bath as a pressure cushion to support the spindle, along the line of the Verdier La platine that I am familiar with.

So I flip the 8000 over and take off the stainless steel central plate (the one with small allen screws that is located in the centre). This plate has some Japanese written on it, if only I could understand that!

I remove this plate and discover an oil bath under the centre spindle and maybe 2/3 full of oil. The oil was clean of a very high viscosity (fluid). Looking at this it seemed that it was designed for "supporting" the bearing spindle, like a pressure chamber much like the Verdier but of a higher volume and built to high standards.

The spindle itself moves up and down very easily and the bearing is "hyper" smooth, the best I have encountered on any turntable.

This “chamber” is air tight with sealed rubber ring (very well done!), the only leakage possible is via the bearing. The tolerance here is high, looks like bronze bushes but with the viscosity of the oil it would require quite a pressure to achieve leakage via the bearing.

So what I do is fill this chamber with thin oil, using oil that Loricraft had supplied me for my Garrard 301 bearing. the aim being to have no air, or the least possible, in this chamber.

After fitting the plate again I turned the TT over. And then I see that the spindle is supported by the pressure, a pressure cushion.

You can see some images of the extent of it’s movement here http://picasaweb.google.fr/timothygurney/MicroSeikiMS8000#

Quite a lot of pressure is required to move it down. This is seemingly a very good design indeed! This would mean that the air bearing lifts the platter and the central spindle is “floating” on oil. This kept reminding me of the Verdier that uses the same approach (copied??) as MS only using magnets to lift platter. The Verdier chamber is also far smaller.

Played records the best side of 6 hours yesterday and no more of that slowing down, so seemingly this “service” has solved that. The platter was running too fast when checked the speed, this does make me think that some friction was introduced albeit not much.

I must admit that I did not note any change in sound, however I was listening to a recent arrival of some very fine Coluunbia CX’s and SLX’s.

I performed this service using common sense (well….mine!) and wanted to know if anybody out there actually knows more about this feature and how it should be serviced?

Have I performed this service correctly?

Hoping this will invite fellow MS air bearing owners to investigate the status of their “oil bath”

Tim
soundlistening
Thanks Tim.
I have yet to do this kind of service. I have to do something similar in any case. Separately, do you know anyone who does Micro Seiki motor repairs?
T_Bone,

You can download the instructions to service the motor from here

http://web.me.com/kip/ry5500/Micro_Seiki_RY-5500_lubrication_steps.html

Used this when I motor was making some noise, the grease had dried up. This fixed it, took maybe 30 minutes to do.

Thuchan did it also, even if he had no issues and in the end uses the VPI motor base.

Then there is this site that is in Japan with "loads" of information on Micro Seiki repair and other brands also. Maybe he can service/repair or could provide some good tips/information ? Being that you master Japanese maybe you could give some feedback if you contact this place ?

http://amp8.com/amp-etc/record/micro/ry5500_3.htm

Tim
Typically the motor spindle runs in a phosphor bronze bush + this dries out, which causes the speed anomaly ( a once every 20-year service ! ) RX-5000's + 8000's. The motor pulley can also slip down the spindle + physically rub against the motor body ( check you have clearance! )+ produce the same symptom

Remove the motor pulley from the spindle ( 2 x small cheese-headed screws )Flip the motor body upside down and remove the allen keys on the base;this will get you to the base of the motor Take off the motor base + withdraw the armature; the spindle will slide out of the bushing Liberally oil the inside of the phosphor bronze bush with light oil ( I use air tool oil ) + leave to soak in overnight Reassemble + enjoy! While the motor is apart, it might pay to very lightly oil the armature as these are iron + they rust; wipe any excess off + gently blow any grit out of the motor base/top Don't touch the delicate screen printing. This is harder to say, than it is to do
No big deal. I did it a few times. That repair instruction was posted multiple times.
I'm returning to audio and found this thread while researching MS air bearing lubrication.

Can someone point me towards a Micro Seiki factory specification for the oil / lubrication used in the main bearing assembly? It appears to be high viscosity, and from research seems to contain lead additives.

Would a 10w40 motor oil, with the addition of the lead additives, be appropriate?

On a related topic, it appears there is no ball bearing between the bearing shaft and bottom thrust plate. Is this correct?

Thanks,

Scott
Hi, Tim
I know it is quite late to post a question now but this was the only thread I could find that discusses the problem I have with my MS SX8000.
My 8000's air bearing doesn't work properly. Sometimes it work w/o no issue but it slows down or completely stops. It is not motor problem but it seems that the air that floats the heavy platter of 8000 leaks somewhere. Hope you can share your experience with me for solving this problem.
Kim
Kim
I am not experienced with MicroSeiki but am somewhat familiar with Air Bearings. Here are a few points that can help you either solve or troubleshoot your issue.
1. Air pressure constant--if your set up does not have a pressure gauge near the platter, get one and install. Platter shouldn't take a lot of air pressure to lift, but if you see it moving around, that could be an issue especially if the issue is transient. 
2. Platter is level--Shouldn't normally be an issue, but i have seen with my maplenoll (80 lb lead platter), being off can lead to some occasional rubbing
3. oil or dirt on the airbearing surface--if you have a residue, sometimes it will cause sticking as the platter is getting lifted. i clean mine with Isopropyl alcohol
4. insufficient air pressure--If you can raise your pressure slightly and the problem is eliminated, then this could be the issue
5. airbearing surface damaged--i have heard that a scratch or gouge can reduce the smoothness of the platter and cause rubbing or excessive friction
6. center pin sticking--not sure how the MS are constructed, but my maplenoll has a pin that centers the platter and keeps it from moving side to side as lifted. I think from the references above, that the Micro has the equivalent it "floats" in an oil bath. A lack of lubrication here would definitely cause this issue. in the Maplenoll, i have a brass center pin that sets in a brass sleeve on one machine and a teflon pin that sets in a brass sleeve in another. but both are lubricated with a light grease. However, this is a source for friction, so check it out also

Hope this helps