I have an EQ3 equatorial mount with GoTo controls which still tracks and guides OK but now emits a loud clicking noise. The noise comes from the RA motor and is usually regular, a bit faster than one click a second, sometimes irregular and occasionally goes altogether. Guiding has no effect. I have checked all the connections of the external plugs and the connections inside the housing. Any ideas.
I have an EQ3 which often has similar problems and I have found it is gears coming out of good mesh. A few minutes with the allan key cures the problem for a few months. I think my problem is not tightening the screws enough but do not want to overtighten.
I usually put some grease on the motor gearwheel at the same time.
Thanks for the suggestions Ian and Rik. I finally got round to have a look at the mount and ended up completely dismantling the RA drive and bearings. The worm was extremely tight on the wheel and turned in jerks and not smoothly. The clicking noises have now gone so I just need a clear night to try it out! I reassembled everything with the minimum backlash I could but there is so much in the gears and worm/wheel I am surprised it works as well as it does. No doubt carefully balancing helps.