Another Successful Surgery

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Another Successful Surgery


Post by JayTee » Mon Oct 07, 2019 1:10 am

As a result of my recent trip, my Celestron SLT Mount azimuth axis had developed a significant amount of slop. It took nearly 10 seconds to get a reversal at the highest motor speed. I believe this came about from inadvertently moving the mount along the azimuth axis with the power off. Many places warn, "don't do this."

I researched how to perform the procedure to fix this, it was relatively straightforward and easy. Included are the link (use only the first two pictures) and attached written procedures.

As it turns out the first steps are quite simple; when you remove the central base bolt the base comes off of the top part of the mount. Now you'll see a large gear attached to the base. Next, inspect that the large gear is firmly attached to the base itself. In my case it was not it, this is what was generating the slop. Fixing this was just a simple matter of tightening the two screws that held that large gear to the base portion of the mount.

The difficult part came in trying to reassemble the mount. This is where I needed my son's help (mostly his eyes). Putting the base with the large gear attached back onto the top portion of the mount so it was seated correctly to mesh with the pinion gear that drives that large gear was really difficult. As it turns out, that large gear can be positioned off-center of the rotational axis and you have to make, in our case, several dozen minute adjustments trying to find that perfect spot that would allow the two gears to correctly mesh. After dozens more attempts at trying to get it to mesh, it finally did. I think it was more a situation where we just got lucky as opposed to we knew what we were doing. In the end, it all went back together correctly, it all works correctly and the slop is gone. So if you undertake this surgery just be advised that the actual removal of the slop is easy the difficult part is trying to get everything back together.

SLT Repair.pdf
(296.34 KiB) Downloaded 19 times ... gt-mounts/

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Post by Don Quixote » Mon Oct 07, 2019 1:16 am

This is a scary proposition JT.
My SLT did something like this the last time I used it. I have been reluctant to delve in. But your post has shed light where there was none before.
Thank you.
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Post by Richard » Mon Oct 07, 2019 3:39 pm

Yes I have had 2 SLT mounts that the screws are loose and give a lot of play , these mounts are getting on with age and lets be honest they are starter go to mounts but work so well Celestron got this one 100%
Reflectors GSO 200 Dobs , Sky-watcher 10 inch Dobs
Refractors Tasco 10TE-5
SCT C5 on a SLT mount
Mak 150 Bosma on a EQ5
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