[Boatanchors] R-390 (Non-A) Help Please (Clarification)

[Les Zwiebel WB6ORZ]

   I may not have stated my problem clearly.
    Besides needing the Dial Zero Clutch Assembly parts, the 
issue with the PTO is... I have the PTO out of the rig. However 
the small, non-metallic, slotted cover screw is frozen, and so I 
can't remove it to gain access to the L 701 end point adjustment 
slug.
    Hints?
    Thanks again.
    (((((73)))))
    Les
    ---===WB6ORZ===---