ALT AZ EQ6 Guide problem

[almcl]

A problem has arisen with my still-fairly-to-me Alt-AZ EQ6.

 

After a couple of months of excellent performance, so good in fact that I didn’t need to guide when imaging using a 200mm lens on my Canon DSLR, as well as excellent guiding when imaging with the 200P, I now can’t get PHD2 to calibrate.  

 

The RA calibration goes according to plan with about 12 fairly evenly spaced steps.  The ‘removing declination backlash’ also proceeds OK, but when we get to the north steps, although initially the mount moves in reasonable sized steps, after a few, movement diminishes until it’s down to nothing, or even going backwards.  Whereas in the past north calibration would invarably be complete in less than 15 steps, now it gets to 50 or more without having moved the required amount. It does seem to matter which bit of the sky is used, either.

 

This might well be down to operator error (or even a random software parameter reset in EQMOD) but what things should I be checking?   

 

[Ant-33]

Have you checked the ASCOM Pulse Guiding settings in the EQMOD control panel? I have the same mount, and I have both the RA rate and the DEC rate set to 0.5. If they're set too low, the number of guide steps in PHD2 calibration goes up. Not sure whether this will help your problem, since you said the DEC steps get progressively smaller. I haven't seen that problem, but it's worth checking that the clutch isn't slipping, balance problems, or wires getting caught and tugging on the mount.

Tony

[almcl]

Thanks, Tony.

Had it out last night and, touch wood, whatever it was has corrected itself.  It wasn't a night for imaging (of course) so everything went swimmingly and the north steps completed in 15 moves!

My guess is it was a balance issue.  With a slight possibility that the polar align was carried out on a star other than Polaris... 

[Ant-33]

Glad to hear it's working now