I bought my 8" LX90 back in October last year, and wrestled with the vibration thing. I decided to go through the scope myself rather than suffer the return cycle(s) that others had described. Bottom line is that I found no one problem to account for the bumping . . . the drive system just seems slightly too weak for the task, and would intermittently stop, then lurch forward at times.

So I did a few things to increase its power and decrease the load. I hooked up each motor to a single AA cell overnight off the scope to break in the motors. I ran the worms on the ring gears for hours to wear in the gears a bit, then cleaned and applied high quality grease, and ran them some more, and re-cleaned. I adjusted the worm play and spring tension to optimal. I found that the ring gears are slightly out of round, and figured a way to mark the high spot and tension the clutches with that spot over the worm to even out the roundness. And I religeously balance the scope.

This kind of stuff is not for everyone, but is quality entertainment for me on a cloudy night. I'm trying my hand with astrophotography on a wedge now, and so far things are going smoothly for an inexpensive fork scope. Err . . . were going smoothly until I dropped the controller last night . . . ouch.

Best,
Rob Crockett