Dob go-to jerky in one axis

[Granada]

Recently noticed that my 14" Dob go-to mount is very jerky when moved up/down. Not as smooth as it used to be or when moved left/right. What could be causing this? I've had it for about 5-6 years, and used infrequently. Powered by a lighter socket plugged into a 240-12v converter, which is plugged into the mains. Not sure if that's relevant info..

[JA]

Hi G,

More than likely it's something like dirt, dust, grit in the grease/oil if there are any exposed bearing surfaces/drive elements. You may be able to test that somewhat if it is possible to decouple the drive drive form the telescope via a clutch/es and then see if there is still any friction or stiffness in the motion when the dob tube is moved by hand. That may help point you towards whether it is a bearing or drive issue.

If you are unlucky and the scope has had a knock during its period of non-use then some sort of drive/bearing misalignment may have occurred. Try the test above if possible to help point you in the right direction. Without knowing your scope it is not possible to say for certain whether you can indeed decouple the drive to test.

Good luck in your investigation, hopefully it's something simple to rectify.

Best
JA

[Granada]

Thanks JA. This is the dob btw: https://www.ozscopes.com.au/skywatch...telescope.html
I'll have a look for dirt and other things you mentioned and see if that's the issue or if I can eliminate it. Kind of hoping it is because I really don't want to have to send it off to someone for repairs and I wouldn't even know where in Melbourne. Bought it from Bintel but warranty is out

[gaseous (Patrick)]

I can't help you Granada, other than to offer sympathy and condolences. My 8" go-to has a similar sort of very slight jerking/sticking in the azimuth bearing motion. I've taken the whole thing apart (twice), made sure there was nothing over/undertightened or dirty, but for the life of me I can't work out the reason for it. I hope you get it sorted, and share your wisdom here! Good luck.

[Granada]

Thanks Patrick, I'll look into it and report back if I figure out what it is and how to fit it

[Allan_L (Allan)]

If you use heavy eyepieces, maybe you might need to add a counter weight to the bottom of the scope . I used to use rare earth magnets to help with balance and then you can reduce the tensioner.
Just a thought.