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Whats the platter o-ring for?

Posted: 28 Apr 2019 04:06
by tep392
So my SLX-3 has what looks like a piece of foam rubber where I believe an o-ring should be. I'm new to these Garrard's so don't even know what the o-ring is used for or where I could find a replacement. Is there anyone selling these, or does someone have the dimensions that I could use to order one? What does it do?
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Re: Whats the platter o-ring for?

Posted: 28 Apr 2019 10:04
by DSJR
That one looks too big for me - 1.6mm by 15 or 17 or so (not too tight a fit around the hub's groove) - and it's there to quieten down the 'cogging' noise when cycling. Too thick and the mech binds up. It's there purely for refinement and works very well - even SP25's had this from around 1970 I remember.

Re: Whats the platter o-ring for?

Posted: 28 Apr 2019 14:32
by tep392
Thanks! I'll try to find an o-ring with 1.6 cross section and appropriate diameter. What's on there now looks like it was cut from a rubber sheet with an Xacto knife.

On the plus side, it looks like the previous owner did a good job of cleaning out the old grease and sparingly applying fresh lube.

Re: Whats the platter o-ring for?

Posted: 28 Apr 2019 20:45
by DSJR
By the other thread. Just make sure the pawls on the cam are free to move against each other and in my experience, dry. You may be able to cheat by spraying a solvent cleaner sparingly on these parts, but it's a bodge and no real substitute for removing them, de-greasing them by hand and then carefully re-assembling. As long as the previous owner hasn't ladled the fresh grease on with a trowel, you should be ok - I'm assuming the trip sliding rod hasn't been messed with, but the arm would 'stick' before side end if this was so.

Re. the O ring. I did my AP76 some years back and initially used a 2mm cross-section ring. The supposedly identical Zero 100 and 86SB basically jammed with this ring in operation and substituting a 1.6mm ring worked for all of them. As to ring diameter, too tight and it'll split all around after a few months. Obviously it shouldn't slide around the shallow locating groove, but shouldn't be a force-fit either. I need to get the 86SB down from storage this next week as I have some alternative motor grommets to try (used from a different Garrard) and the platter is easier to remove for checking the diameter of grommet needed.

Re: Whats the platter o-ring for?

Posted: 29 Apr 2019 03:41
by tep392
I've already removed the platter bearing housing, so it probably isn't a lot more work to remove the cam wheel. For the oring, I can borrow a digital caliper and measure the diameter where the oring sits. I'll choose an oring with ID about 95% of that. Should fit just snug enough.

Re: Whats the platter o-ring for?

Posted: 02 May 2019 04:07
by A70BBen
Whatever you grease, don't apply any to the auto trip levers or the slide that operates them. They must run dry. Any lubricant will cause drag, especially as it dries out, and you will be doing it again.

Re: Whats the platter o-ring for?

Posted: 02 May 2019 19:33
by tep392
I measured the inner diameter of the o-ring groove at 15.7 mm, so I ordered some 15mm o-rings, with several cross sections to try out. 1.5, 1.8 and 2.0mm Hopefully one will work. OD of the splines on the platter is 20mm.

Re: Whats the platter o-ring for?

Posted: 03 May 2019 13:01
by DSJR
1.5 should do it. I think I mentioned that my AP76 (different platter and hub to yours but should have been the same as the Zero 100?) worked with 2mm cross section although the ring began to break up in the outer edge after half a year or so. The 86SB and Zero 100 all but jammed on the 2mm section rings, but were fine and quiet with the 1.5 or 1.6mm rings I bought and still seem ok several years on, so the 15 x 1.5 you've ordered should be just perfect I reckon - it's just there to smooth the 'engaging gear teeth' noise otherwise heard, that's all.

Re: Whats the platter o-ring for?

Posted: 03 May 2019 17:57
by tep392
My Jico M91ED stylus arrived yesterday! I'm just waiting for a new platter bearing cushion ring to arrive so I can put it back together. The old one was flat and hard. I'm looking forward to trying this turntable out.