iOptron CEM40 Instruction Manual page 50

If you feel there is free play between the worm and gear, you may tighten the gear screw to eliminate it.
To Adjust RA Gear:
The RA gear meshing adjustment screw is located next to the RA Gear Switch. The adjustment is same
as that for DEC gear/worm.
5mm
3mm
DO NOT over tighten the gear meshing adjustment plunger to avoid damage it.
Please contact support@ioptron.com if you need more information.
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