4 replies to this topic

[Rel1951]

Hello! 
 

I recently purchased the SA GTI. The RA and Dec axis is so stiff that I can’t balance the mount. This causes guidance to go crazy bad.

 

Does anyone know how to loosen these to make rotation free enough to achieve balance?

 

Thanks

[BucketDave]

My LX85 mount had the same problem. I managed to free up the DEC axis by sanding away some of the metal on the casing where it contacts the bearing.

I suspected that the bearings weren't properly aligned with the DEC shaft.

If your SA GTi is new, I'd get it swapped for another, or get your money back. I have an SA 2i and the RA axis is not exactly friction-free.

[Mikehuerto]

Hello! 
 

I recently purchased the SA GTI. The RA and Dec axis is so stiff that I can’t balance the mount. This causes guidance to go crazy bad.

 

Does anyone know how to loosen these to make rotation free enough to achieve balance?

 

Thanks

I have a similar issue with stiff Dec and RA axis. I've searched extensively for how to loosen up the axis, and the best I found was this video on what I think is an AZ/GTI. He completly dissasembles the Dec clutch and cleans things up.

 

https://www.youtube....h?v=VrEkdtMfqLQ

 

I'm on the fence as to whether to form such open heart surgery..

 

Mike

[Rel1951]

Thanks Mike, I saw that video earlier. I've returned the mount. I can't see having to fix a brand-new item.

[Mikehuerto]

For anyone else reading this post: Reading around, clutch stiffness appears to be fairly common feature of the GTi SA.  So, instead of open heart surgery, I ended up determining the Dec balance point by balancing the camera assembly & lens  on a pencil on my desk - its a very light and compact Samyang 135 mm+ASI294MCpro -  and then clamped it at that point on the mount. Also added some more grease, to the Dec worm drive, and tightend the Dec backlash screw, to get backlash down to  350 ms, as determined by PHD2s guiding assistant, and then adjusted a few of the PHD2 DEC settings. Ended up with  an average Dec RMS of 0.29, and a total average RMS of 0.46 after a 50 min guided run. I think I can still optimize further. But, bottom line, if you guestimate the true balance point of your rig, I dont think the stiff clutch is necessarily a barrier to good guiding. 

Edited by Mikehuerto, 28 November 2024 - 01:52 AM.