Poor focus on an Admiral 20Y1

[Kamakiri]

Been working on this Admiral 20Y1, and I'm stumped.

I can get the focus somewhat close by cranking the control clockwise, but I can't get it locked in. The control is smooth and linear....in other words, it works fine but just doesn't have the range to lock in the focus.

To begin with, I've done a complete recap of the set.

I have replaced and tested every resistor in the focus circuit. I have tested and then subbed the focus coil with one off a parts chassis, to no effect. I have subbed the ion trap. I have tested all the tubes of course, and subbed the 6SN7 and the 5U4 just for grins, and no change. There are no wiring errors that I can spot, and I've been working on this focus issue for at least 6 hours and have been through the schematic with a fine tooth comb.

Link to the Sams:

http://www.earlytelevision.org/pdf/A...Sams_100-1.pdf

AGC, brightness seem to be operating fine, sound is good, but the horizontal and vertical lock aren't very stable either.

I'm stumped as to where to look next??