Fixing the CGE Pro Declination Axis “Slop”


A few people have encountered an issue with their CGE Pro where there was some play in the declination axis. I noticed this, as well, and finally decided to open the gear box and see what I could learn. The fix appears to be relatively simple.

Here is an image of the motor, gears, their support frame, and the support frame that attaches the motor drive to the mount.

Mounted to the declination axis is an aluminum plate where the gear box housing is mounted (it was removed prior to the photo). On this plate, a support frame is mounted (red arrows). The motor and gear assembly (black arrows) is mounted on the mount support frame by the two nuts on the mount support frame. These nuts attach to bolts on the gear and motor assembly frame.

The tension on these nuts controls the distance between the worm gear (under and parallel to the motor) and the declination gear. However, if these nuts are loose, the gear and motor assembly frame can move laterally relative to the mount support frame. This is what causes the “play” in the declination axis.

Also, this is a tuning issue with the mount. Setting the correct pressure to fully engage the motor’s worm gear and declination axis gear is important to ensure minimum backlash in the gear without binding the gears against each other. So, by using the combination of nuts, the pressure and “tilt” of the gear can be accurately set.

At this point, play could result from 1) the nuts holding the motor and gear assembly frame to the mount support frame being too loose; or 2) the worm gear being too far from the declination gear. I found that when I wiggled the declination axis, the entire motor/gear assembly moved slightly.

Shown below is another view of the nuts holding the motor frame to the support frame. I turned each of the nuts clockwise 1/4th turn and eliminated the play. The worm gear seems to be firmly engaged with the declination gear and when I mounted a scope on it, the play is gone and everything appears to be working normally.

Those who are not able to get the motor fully secured without disengaging the worm gear from the declination gear could get some teflon washers and place them under the steel washer. It’s possible that when they configured the mount at the factory, they didn’t use enough spacers to keep the motor secure under heavy loads (I run my rig with about 60 lbs on it, so that may have help loosen things up).

Just be careful when fully removing the gear box covers that you are careful to remove the blue connector from the circuit board on the lower cover.


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