Need "BTDT" help with Logic DM-101 bearing


Hi All,
(comment: no turntable topic/area?  really?)
I'm looking to find someone with enough experience to either guide me away from trouble or assure me none exists as I try to fix a problem with my old Logic DM-101.  Basically, the ball bearing that provides a point contact at the bottom of the spindle easily gets off center.  I'm trying to understand 1) why?, 2) how to remedy and 3) can i simply take the bearing out of the sub-chassis and work on it more easily.
One would think the ball would fit in the sleeve and not move. Not true!  Apparently there is a cavity down there and it can move off center, causing small but sometimes audible wow.
PM me if you like or reply here.  TIA,  -G
itsjustme
Why? Its a crap design. Turntables are really simple, but nobody can be bothered to try and understand even simple things any more, so there's a profit to be made separating fools from their money. That's why.

Bearings are simple enough and been around long enough you'd think they'd know better. Heck Chris Brady and a few others developed the Teres turntable bearing and mine's been running over 16 years perfectly trouble free. Cost about $250, and every new table I look and so far only the Onkk Cue strikes me as being definitely better. Probably. But that's a $30k turntable. Tables under a grand the individual parts costs drop dramatically to disturbingly near zero. Have to. Economics. Just one reason why the idea of diminishing returns in audio is nuts. 

In the Teres design the ball bearing fits snug in a spherical cavity cut into the spindle and rides on a thrust bearing, basically just a flat piece of metal at the bottom of the bearing well.

Yours seems to be the reverse, with the spindle end serving as the thrust bearing and the ball bearing just sitting in the bottom free to move around. What moron came up with that? The moron designed your turntable. These things are simple but every little detail matters. A lot. There's reasons expensive tables are expensive. Live and learn.

So yes, remove the bearing. Take it apart. Clean. Study. Sounds like you just need something to keep the ball in place. Also need something to center the ball. If it was in front of me where I could see it the solution would be apparent, believe me. Only thing makes it hard is guessing. My guess is, just the right size blob of Blue Tack goes down in the well. Just the right size being just big enough to fill all the space around the bearing, not so big it stops the bearing from seating all the way at the bottom. Drop the ball in.

Take a piece of paper, roll it up into a tube, just the right size and thickness to slide down the tube, center the ball, and press it securely into the Blue Tack.

Reassemble. Hand test. Modify and repeat until satisfied.


This sounds like a hopelessly poorly designed, under specified, improperly manufactured turntable using insufficiently engineered components you might as well buy a new machine this one seams without repair.
I do plan to take it apart and fix.
Can we get back to "who has taken the bearing out of the sub chassis and can guide me to any pitfalls". i Don't have tome or interest in wasting time where i can avoid it.
Millercarbon - what's your experience with the Logic?  Its a remarkable table in many ways.  I do not (yet) know why mine has this oddity.
Thnx,
G


Hi itsjustme.My extensive solution to your bearing problem was not posted 21/02/20 for some reason. This site is inconsistent. I have given up after 2nd attempt.Steve.
PM'd you and heard nothing... please reach out, Thanks, G