I'm not person who posts often (well very rarely at all), but I received a CGX mount that has a DEC guiding/backlash issue and was extremely tight in the DEC axis once the clutch had been released. Making it almost impossible to balance.
I have not yet had a chance to test yet....dam clouds....but what I determined is that the primary cause for the poor DEC backlash was to do with the fact that the free play was so stiff. When the clutch is engaged, the worm gear rotates around the ring gear. So my thinking is that there has to be increased strain on the motor drive system to move the axis, which makes me think that this mechanical strain would translate into the guiding too. (note I have tried adjusting the worm drive block, without any improved success).
I used to own a CGEM and performed my own hypertune and I remembered over tightening the tapered ring bearing in the base of the axis and this gave me the same feel in the effected axis. So with tools in hand (yes this mount is out of warranty) I started to dismantle the bottom of the CGX. I have to say the electronics are not that bad down there, a very simple IO board with opto switches on the PCB. Removing all that reveals the bottom of the axis and the nut which locks against the tapered bearing. Using the tips of my long nose pliers I was able to free the nut (there is some loctite on this nuts thread). With it loosened I decided to take the tapered bearing out completely and clean it up and then apply my hypertune grease. Make sure when you reassemble to add some loctite back on the thread. I tweaked and tweaked it so that the tapered bearing is nice and snug, but not over tightened, I think you will agree from the before and after videos that I've definitely made an improvement.
I've read lots of posts and seen videos of other peoples CGXs and the problems they have been having, so I hope maybe this will help someone.
Problem very stiff DEC axis
DEC and RA After Adjustment
As mentioned I've not had a chance to test anything yet due to clouds....but I'm pretty sure this is going to be an improvement.
Edited by narcosisnz, 09 December 2019 - 01:43 AM.