CGem balance/power?

[Tony Rodda]

If anyone has any ideas/pointers I'd be grateful...

At the RA east/west point where the counterweights pass through their lowest position ('down, pointing North) the mount seems to choke in RA.

By that I mean the motors/gears start to tick loudly and, in one instance, it became very loud and the mount stopped tracking.

Pushing gently in the direction of RA motion stops the problem (resisting the RA motion exacerbates it) so I initially thought it a balancing problem. Not so.  The mount only carries a 9.25 SCT, filter wheel, SXH9 and standard finder.

Playing around with various weights doesn't really help.  Nor do different power supplies.  (I thought perhaps the motors weren't powerful enough to drive through that unbiased RA position or that there was some 'stiction').

The only way I can solve it is by an unduly weight bias in the direction of RA travel.  (Just the opposite of a East bias!).  That means manually changing the weight positions at the sticking point.

I've had my CGEM mount for over a year and it's performed remarkably well for mass-produced mount.  It guides very well apart from the 'down, North' position corresponding to 90/270 degrees).

Anyone any ideas?  Is there an adjustment or further balancing act?

Regards

T

[chrisg18]

try to adjust the worm gear allen screws. look  on cloudy nights there is a brilliant article showing this