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cyto
06-08-2019, 21:46
My 1200 M3D developed a problem a few weeks ago. I noticed the tonearm kept drifting to a spot just outside of where a record starts. It does it with the anti-skate at 0 or at full, the anti-skate works and pulls the arm as it should, it still drifts back to that one spot.

I replaced the tonearm tube with a carbon fiber tube about 1 1/2 years ago, thread here https://theartofsound.net/forum/showthread.php?57062-Another-DIY-carbon-fiber-tonearm&highlight=carbon+fiber+tonearm

I took it apart and double checked the wiring and that is not the problem. It shouldn't be anyway as the turntable has not been moved in over a year so there is no reason that the wires would have shifted. But I checked anyway.

I also tried adjusting the bearing that controls the horizontal movement. Tightening it slightly made it worse and loosening it slightly didn't change it.

To me it looks like the horizontal bearing has developed a notch.

KAB no longer sells replacement tonearm assemblies and they are $250+ on eBay (new), and I really don't want to buy one on the bay anyway.

What do you guys suggest?

Thanks,

David
Audio Al
07-08-2019, 07:52
https://www.youtube.com/watch?v=IcUwade94EA
cyto
07-08-2019, 16:29
I even thought about making an arm around this:

https://www.ebay.com/itm/New-turntable-plattenspieler-phonograph-tonearm-DIY-parts-for-RB202-RB251-GR1/111378499741
Audio Al
07-08-2019, 16:42
Jelco arm ?
cyto
07-08-2019, 17:35
Jelco arm ?

It is supposed to be most of the parts to build a Rega RB202
Audio Al
07-08-2019, 17:44
It is supposed to be most of the parts to build a Rega RB202

As a alternative arm a Jelco , some members have used them on 12-- TTs
cyto
07-08-2019, 18:39
I thought that I had nothing to loose so tried this.

Instead of loosening the locking collar on the horizontal bearing and adjusting the center screw, I completely removed the locking collar first. When I pulled the locking collar off the bearing had an incredible amount of play. So also removed the pointed adjustment screw and put a drop of spindle bearing oil on it. Then I put the adjustment screw back in, tightened it until the play just did disappear, then I put the locking collar back on and tightened.

Now the tonearm is gliding smoothly just like it is supposed to! No drifting except when responding to antiskate adjustment.