[Heathkit] SB dial question

[wb8jkr@juno.com]

   I'm in the process of rebuilding a SB-401 transmitter,
it was modified sometime in the past with a solid state
LMO probably out of a SB-102 and has other holes
drilled in the front panel. Anyway, I'm going to put an
original 401 LMO back in the unit and I have a NOS
front panel for it. My question is what should I be aware
of, careful of, any hints and kinks in dealing with the
SB series dial drive etc. 
I'm pretty well versed with Heath units electrically but
I've never had a SBseries dial assembly apart or
removed/reinstalled a LMO in a assembled unit.
 Any input from anyone who has done this would be great,
I don't want to screw anything up.

73,  Mark  WB8JKR