Garrard 'Type A' / A70 noisy bearings, advice needed

MonoMania

Member
The past few months I've been getting immense enjoyment from a Garrard 'Type A' autochanger, and have been gradually going over the mechanism, cleaning, lubing, upgrading with parts from an A70, etc.

Performance kept getting better and better, until I reached the last step I had been putting off: disassembling and cleaning the main platter / spindle ball bearing assembly. All I had done to these bearings previously was put in a few drops of sewing machine oil.

I finally attempted it today, after noticing a slight mechanical rumble (not through speakers).. I figured that I was hearing friction at the bearings, and that this must be contributing to the slight non-distracting rumble being picked up between tracks by my mono cartridges.

I removed the platters, loosened the two copper-colored horizontal retaining screws which hold the spindle in, pulled everything out... I soaked the parts in isopropyl alcohol, cleaned thoroughly with q-tips, rinsed again with alcohol to get rid of any errant fibers... I left to dry, coated lightly in oil, put a tiny amount of grease (ParkTool polylube 1000) in the bearing races, and reassembled in what I'm sure was the correct order (bottom to top: rubber ring>metal washer>bearings>metal washer), observing which side of the metal washers should face the bearings based on visible wear patterns...

I reassembled the spindle (took a few tries to figure out), put in a few more drops of oil, and put the platters back on.... Now the mechanical noise is WORSE than before, particularly noticeable on 78rpm.

The noise is definitely coming from the bearing assembly. The bearings are definitely all present and seated correctly in the race (which seems to be made out of phenolic wafer).

Can anyone point me in the right direction?

Have I overlooked something obvious? Is my cleaning methodology wrong?

Does anyone know of a source for replacement bearings?

Is it possible to further upgrade these bearings, races, and washers?

I have scoured the forums before posting - in fact I think I've read every word written on the internet about this particular model. Would be a drag to have to get a whole new 'Type A' after months spent improving this one... And I'm keen to continue my adventures in stacking 45s and 78s and enjoying classic monophonic 50s-60s cartridges.

Any advice would be greatly appreciated!


P.S: I'm determined to cobble together the ultimate 'Type A', and am willing to continue to pour money into it, well-aware of it's inherent limitations, so "get yourself a better turntable" is not the advice I am seeking here!
 
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I replaced bearings on a Garrard Lab 80 once. Viewing the old bearing under a machinists microscope, I could see flat spots on the bearings. I don't recall the size, could have been 5/32" but I think @marcmorin knows the correct size.
 
I don't know the size of the bearing ball in a Garrard, but i probably have a correct size. but as they say, it takes two to tango. if there is wear on a bearing ball, what rides on it has wear also.
 
I've found an answer to part of my question - ball bearings for the Type A / A70 family are available!

There is seller on that famous auction site who sells many miscellaneous Garrard and Dual parts. He didn't have the bearings listed on the site, but was able to provide them when I inquired, and at a very reasonable price.

The washers do have visible wear paths on them though, so as @marcmorin has pointed out I may need to source replacements for those as well, or attempt to polish them.... They seem to be specialized washers, made of two layers, the thin layer which faces the bearing I assume is hardened and polished.

I will inspect the old bearings under a microscope as @malden suggested when the new ones arrive; I didn't think to do that while I had them removed.
 
I've found an answer to part of my question - ball bearings for the Type A / A70 family are available!

There is seller on that famous auction site who sells many miscellaneous Garrard and Dual parts. He didn't have the bearings listed on the site, but was able to provide them when I inquired, and at a very reasonable price.

The washers do have visible wear paths on them though, so as @marcmorin has pointed out I may need to source replacements for those as well, or attempt to polish them.... They seem to be specialized washers, made of two layers, the thin layer which faces the bearing I assume is hardened and polished.

I will inspect the old bearings under a microscope as @malden suggested when the new ones arrive; I didn't think to do that while I had them removed.
can you post some photos of these pieces? The spindle end, etc
 
I've attempted to photograph all of the relevant parts - let me know if I've missed anything @marcmorin

All of the bearing assembly parts separately:
image.jpg


Spindle with bearing assembly put together:
image.jpg



I'm assuming that the worn side (right side photo) of the washers is meant to contact the bearings:
image.jpg


Both side of the spacer (note wear on one side) :
image.jpg


The bearings under a microscope, but the photographs unfortunately didn't turn out well.... There is some pitting visible under 100x magnification - is this wear/corrosion? Or a manufacturing flaw? Much of what is visible in the photos is dust. The bearings are shiny, no skid marks like you would expect if they had gotten stuck. Not sure about "flat spots", they looked round to my eye, and the photos I took are distorted, so not good to judge by.
image.jpg


Included for completeness: the place where the spindle assembly sits, held by two horizontal screws underneath:.
image.jpg
 
personally I would simply dress the flat thrust plates, and replace the current balls with boca ceramic balls. The imperfections on the ball could have been simply due to ball grading, or the plates were to the finish of the back side of them which is fairly poor and the bearing balls are reflecting that.
 
I'd try running the thing nonstop for 24 hours or so to see if the noise abates.
When I've replaced bearings (whether ceramic or otherwise) on tables that use a race like that I've found running them in helps. Putting a bit of extra weight on the platter helps them wear in faster, too.
 
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@marcmorin, How does one go about dressing the thrust plates? Is that just a matter of polishing them?

I googled "how to dress metal", and received some great advice about leather jackets and hair dye.

I will look into getting a set of ceramic bearings from Boca; I just need to figure out the correct size, and I don't have a micrometer...

Am I correct about which direction the thrust plates are supposed to face?

Thanks to everyone who has replied!
 
I've consulted with a bona fide Garrard expert (who sells Garrard and 'Dual parts' on that auction site), and he provided a crucial piece of information:

The two washers (thrust plates) are not identical - one has a smaller inner diameter than the other to accommodate the gear spindle. Obvious now that I look at it.

I haven't yet checked to see whether this was the source of my problem, but odds are 50%!
 
marcmorin, which sort of ceramic bearings are suitable? Boca offers 'ceramic alumina oxide', 'ceramic silicon nitride', and 'ceramic zirconia oxide'...
 
So I took it apart again, cleaned, re-lubed, and reassembled in what I'm now certain is the correct order (thrust plate with larger inner diameter goes on top).

Still some noise at 78rpm, but less than before, and presumably less than before the initial cleaning.
I'll listen to it tonight to try to get a sense of whether the cleaning reduced audible rumble any.

At 33 rpm I have to put my ear right beside the machine to hear any noise at all.
At 78rpm I hear some slight noise from 2 feet away; which only becomes really noticeable if I stand right over the table.

I wonder, was the 'Type A' ever expected to run completely quiet at 78rpm, even when new?

I'm now following @kirk57 's advice and running the table at 78rpm (with a stack of ten 78s for weight) - it does seem to be settling down further after a few hours.

Haven't yet followed @marcmorin 's advice about dressing the thrust plates, but I intend to as soon as I can track down the right sandpaper.

Still not sure of the differences between Boca's 'ceramic alumina oxide', 'ceramic silicon nitride', and 'ceramic zirconia oxide' bearings.
I have a fresh set of steel bearings in the mail, and plan to order a set of ceramic bearings as well in hopes of getting the table even quieter.


Thanks again to all who have replied! Every bit of information has helped!
 
If you haven't already done so, consider having the idler wheel dressed. That will go a long way to reduce rumble.
 
Unless Marc corrects me, I'm going to say the the SiNi bearings from Boca will be the hardest and smoothest bearings.
I recently did a sapphire thrust plate and silicon nitride bearing mod on one of my tables and it is like night and day. Ultra quiet with a super long run down time.
 
Unless Marc corrects me, I'm going to say the the SiNi bearings from Boca will be the hardest and smoothest bearings.
I recently did a sapphire thrust plate and silicon nitride bearing mod on one of my tables and it is like night and day. Ultra quiet with a super long run down time.
Correct. the SiNi balls will be best to run on the surfaces in this particular table. Not to alarm you though, you might check that sapphire plate from time to time.

edit: belay that comment.
 
A month later, I'm still been fiddling with my 'Type A', and rumble is decreased, but I have further to go yet.

I polished the thrust plates, and installed a fresh set of steel balls - this made a noticeable difference to mechanical noise and rundown time (nearly 2 minutes now from 45rpm to a complete stop!) but I can still hear some friction at 45 rpm, and quite a lot at 78 rpm.

[Edit: removed misinformation about bearing dimensions, see correction in post below]

If/when I succeed in upgrading this turntable satisfactorily I plan to create a new thread detailing everything I've learned in the process of cleaning, restoring, and upgrading the 'Type A', with photos and illustrations. Would be great to put the knowledge I've acquired from many sources succinctly in one organized thread. In the meantime any and all enthusiastic 'Type A' / 'A70' owners are welcome to PM me to discuss and share info!
 
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