A lot of problems with the RA tracking accuracy can be traced to the free play in the worm and spur gears of the RA drive. These shots are from the bottom of the RA housing after the cover plate has been removed. It is possible to remove the control panel and adjust the free play with the scope set up and mounted on the wedge.
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Here's a shot of the free play
adjustment screw of the RA drive. Notice the gap (lower highlight)
between the end of the sets crew and the frame of the motor
bracket. Also note the top end of the screw projecting from the
bracket.
If you can rock the forks back and forth in RA with the RA lock set, this screw has come loose. In severe cases you can see the worm mesh and un mesh with the ring gear when the forks are moved. You should barely be able to perceive any play in the RA if this adjustment is correct. |
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Set screw after adjustment.
Use a little bit of fingernail polish on the threads to keep the screw from backing out. DO NOT use red Loctite! I am working on a set screw with lock nut variation to allow adjustment without having to worry about the screw coming loose again but still allowing future adjustment. |