Tonearm bearing are set by touch and back off. That means the pin bearing is brought into the race until there is no slack or play without forcing, then the pin is turned back say 10/20 degrees depending. At that point, there is just enough discernible play in the bearings.
From here on, a horizontal and vertical bearing test should be performed.
Here is the procedure to check both planes:
1. Set arm for zero tracking force and zero antiskate force.
2. Balance arm perfectly (perhaps without stylus for safety) .
3. * Place arm between platter and rest post, so it can descent. *
4. Drop a stamp on the head (over cartridge).
Arm must descent all the way for the 1200 series, most of the way for 1000 series with tk 12 headshells and at least lower somewhat for 1009, the lower, the better obviously...
If arm moves without hesitation then vertical bearings are ok.
*Note: for the 1219/1229/1229Q, there is a rubber bridge mounted left of and into the rest post, pivoting on a chrome shaft. This rubber bridge can be shifted/removed to enable a proper vertical test.
1. Balance arm as before (no stylus-no stamp...)
2. Apply 0.5 anti-skate on any side of the Anti Skate dial under the tone arm.
3. Bring arm towards center of record.
4. Let arm go.
Arm must return all the way back to rest post without hesitation.
If arm moves without hesitation, then horizontal bearings are ok.
That's it for the test.
Klaus Adlhoch, fmr. Assistant Service Manager,
Noresco -N.Q.I.-Dual of Canada,
Area of expertise: Tech Training and Consumer Service P.R.
Associated with Dual till Thompson era.
Favorite Duals: TG 12a, 1009, 721.