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Update: AVX Mount with Jammed Centre Rod Replaced

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#1 matso

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Posted 07 July 2014 - 03:52 PM

Hey all!

So I was surprised this morning to find a large box outside my door. Celestron replaced my previous mount. If you recall, it had a completely seized centre rod that took me about 3 hours, a bunch of PB Blaster, and a good amount of sweat to remove.

I very cautiously assembled the new (and tested by Celestron QA) mount after applying a bit of anti-seize compound on the threads, just for good measure. The machining of the threads was visually much better that the old mount. It threaded in nicely - and unthreaded just as nicely. Like butter.

I then moved on to the rest of the mount.

Which is where I believe I have yet another flippin' problem.

The RA and Dec movement on this mount is stiff. VERY stiff. Like it's been lubed with a tacky, glue like material. Speaking of lube there is a bit of the stuff visible around the RA/Dec axes..it looks like petroleum jelly. Some of the stuff is visible in the area of the clutches.

RA is tight, but not as tight as Dec. I have to use a good amount of force to move it in Dec. Yes, the clutches are fully disengaged. But it feels like they aren't - if that makes sense. Things are so tight it's very difficult to get a sense of whether I'm balanced or not with the OTA attached. When I move my scope about to assess balance it just kind of sticks no matter where it is. This is a definite change from my first mount - that thing was smooth.

So all this being said, some 'fake' alignments and tracking seem to work ok; the mount moves smoothly and seemingly without difficulty when driven by the motor. It might be a bit louder to my ear than the previous, but hard to say for sure.

Is there anything I can do to 'loosen' the movement of the scope in RA/Dec. I've been kind of moving it back and forth this afternoon but it seems as stiff as ever. Could the clutches, even when disengaged, be somehow dragging the mount and preventing fluid motion?

I really don't want to send this back again. If it has accurate goto and tracking, I will be happy. It just worries me that things are so tight I might be out of balance without realizing it, and that might put undue strain on the motors.

Obviously a little frustrated with Celestron QA at this point... but hoping that there is some sort of fix possible.

Thanks all for any assistance.
matt

#2 nodalpoint

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Posted 07 July 2014 - 05:42 PM

The mount will work fine, just give it a try.

#3 rmollise

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Posted 07 July 2014 - 05:54 PM

The mount will work fine, just give it a try.


I second that. :cool:

#4 matso

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Posted 07 July 2014 - 07:25 PM

Will do. Like I said, it seems to slew just fine. And this could be hard to believe, but it might actually be clear tonight. At least clear enough. Will give it a go and report back if first light successful. Thanks again.

#5 wargrafix

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Posted 08 July 2014 - 09:18 AM

good luck man!

#6 matso

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Posted 08 July 2014 - 08:14 PM

Success! Got it out last night. Finally got a chance to use my new C8 SCT with it as well. What a beauty. Goto bang on after a 2+4 alignment. Saw more last night, even with the moon out and bright, than I ever have before. And no more nudging my little table top Dob every 6 seconds. Just sit back and observe. It was great.

So the mount tracked and behaved just fine. But I'm still just a tad concerned about how I can ensure I have everything balanced right. I intentionally put things way out of balance prior to using it, and the axes are so stiff things barely moved. It just worries me for long term durability of the motors. But since everything worked fine, I'm happy as it stands. Maybe over time things will loosen. Maybe I'll consider after market clutches. We'll see.

Thanks for all the help along the way.
matt






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