Author Topic: Celestron AVX Rebuild  (Read 10 times)

revekosque

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Celestron AVX Rebuild
« on: December 24, 2017, 04:32:31 PM »
Ok people, I will post this, since I believe it's applicable.

I've never really been happy with my Celestron AVX bracket.  Most of us know what a disaster that they are, or at least most of them.  The design is far from world class, it's a bottom dweller.  I've really wanted to send out my mount for a HyperTune, but spending nearly $500 for that support for an $800 or $900 mount only seems a waste.

I've discovered a better way!

http://rocketsparrow...estron-avx.html

This gentlemen detailed the breakdown of the AVX bracket and the way he went on rebuilding it into something such as it ought to have been to start with.  Anyone who has or has had an AVX, also has gone to perform the gear net adjustments know how greasy these things happen.  Well, when you put into the guts of it, you'll find it's even worse, possibly because there's too much grease, or, on the R.A. axis on mine, nearly none in any way!

I spent this afternoon doing so 'cleaning', for lack of a better term.  It took me around three hours or so.  The instructions are fairly detailed, you can see my comments at the end of the blog, and you might want to read these before you start, there's some things he missed, or even forgot to put in.

But if you have an AVX bracket, and have some basic hand tools, including a good set of Metric Allen Wrenches, you need to be able to get this done in a few hours, most certainly a Saturday or Sunday afternoon.  I'm hoping that this can make the AVX a better bracket for those who have one.

Oh, by the way, I can actually balance in Dec now, in addition to R.A.!!  Could not do that before!



ithoclirans

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Re: Celestron AVX Rebuild
« Reply #1 on: December 28, 2017, 07:59:07 PM »
Quote
I've never really been happy with my Celestron AVX mount. We all know what a disaster they are, or at least most of them.

Perhaps more accurate to say some AVX's are problematic. Mine has the sticky grease but it actually guides very well.

Good to have the strip down reference though if it ever does need attention.

Patrick Zhu

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Re: Celestron AVX Rebuild
« Reply #2 on: December 31, 2017, 06:40:18 PM »
Thanks for sharing this, Gary! This is going to come in handy for when I strip down my mount.

breakagalkit

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Re: Celestron AVX Rebuild
« Reply #3 on: January 10, 2018, 10:41:46 PM »
I just took the gearbox apart tonight, tightened up the play in the gears and regreased. I tested it with motor speed set to 3 and I could see both gears actually move instantly when I pressed a directional button. Before it would be at least a 1 second delay. Hope this improves things a bit at least. Might have to move on to this next.
Question: do you use the anti-backlash on the hand control? I've heard some say it helps with guiding, others say it interferes with guiding.

ifaclidis

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Re: Celestron AVX Rebuild
« Reply #4 on: January 10, 2018, 11:51:18 PM »
Quote
I just took the gearbox apart tonight, tightened up the play in the gears and regreased. I tested it with motor speed set to 3 and I could see both gears actually move instantly when I pressed a directional button. Before it would be at least a 1 second delay. Hope this improves things a bit at least. Might have to move on to this next.
Question: do you use the anti-backlash on the hand control? I've heard some say it helps with guiding, others say it interferes with guiding.

Jarrett, one thing you want to make sure is that there IS some backlash in the gearing, you need to have that, and it's very easy to mash the two gears together and tighten everything down.

As to the Anti-Backlash control, I don't use it, so I can't really say.

lorndwatassi

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Re: Celestron AVX Rebuild
« Reply #5 on: January 11, 2018, 02:26:17 AM »
Quote
I just took the gearbox apart tonight, tightened up the play in the gears and regreased. I tested it with motor speed set to 3 and I could see both gears actually move instantly when I pressed a directional button. Before it would be at least a 1 second delay. Hope this improves things a bit at least. Might have to move on to this next.
Question: do you use the anti-backlash on the hand control? I've heard some say it helps with guiding, others say it interferes with guiding.

If your guiding with PHD, you must have "backlash compensation" disabled in the HC.

The part# for a replacement bearing, taken from another tear down is, Part# bearing 51107. Google it, there are many suppliers on the cheap!

Here is yet another detailed tear down of the AVX...https://www.flickr.c...N04/14934150119

hiswacoka

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Re: Celestron AVX Rebuild
« Reply #6 on: January 11, 2018, 05:29:06 PM »
Quote
If your guiding with PHD, you must have "backlash compensation" disabled in the HC.

Could you please explain why?

As I observed, "backlash comp." is momentary increase of motor speed when slewing opposite direction.
If there is backlash, not compensated mechanically, and if right value chosen in HC,
then this feature improves guiding.

However the best is to adjust gears and make backlash as low as possible.

P.S. I agree that wrong value of backlash compensation in HC can make guiding with PHD like a pain.