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CGEM Failure

Celestron
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20 replies to this topic

#1 CJW8

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Posted 25 March 2019 - 04:27 PM

I just started imaging last night with my Celestron CGEM mount with Nexstar+ hand controller.  I got 3 photos, then the next 3 had long star trails.  I picked up the hand control and it was totally blank with no response to any buttons.  Mount quit tracking, thus the star trials.  The power light on the mount seemed to be blinking but it was a very fast blink never really going completely out.  I checked all the connections and the battery bank was at 12.7 VDC.  I cycled power a couple of times with no luck.  I read a lot online this AM and seems it could be motor control board or the hand controller itself.  Any ideas?


Edited by CJW8, 25 March 2019 - 04:28 PM.


#2 rmollise

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Posted 25 March 2019 - 04:29 PM

Could be any number of things. First step in troubleshooting? Suspect battery/power cable and check/switch them. Was the battery at 12.7 without a load? That sounds reasonable, but if you don't have another power source, I'd throw a charge on the battery and try that.


Edited by rmollise, 25 March 2019 - 04:36 PM.

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#3 Paul Skee

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Posted 25 March 2019 - 04:58 PM

As pointed out, ensuring an adequate power source is essential. Carefully inspect the DC in port of the mount. It must make solid contact with the outer and the inner conductors of the cable.



#4 Andrewf

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Posted 25 March 2019 - 05:09 PM

My CGEM tried to do something similar to this.  My issue had to do with the center pin on the power connection.  You will see the center pin is split in half.  A small wooden wedge like a toothpick will spread the pin slightly and make for a much better contact with the power cord.  Maybe you have the same problem I did.  Easy free fix.

 

Andy



#5 wrnchhead

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Posted 25 March 2019 - 05:27 PM

All good advice. I have had a couple of (OEM) cords for my AVX, and sometimes they get that loose pin tension thing, and a light nudge is enough to power cycle the mount. Mine doesn't have the split center pin, but I am considering opening it up and doing some kind of more secure maglock connector system. 



#6 CJW8

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Posted 25 March 2019 - 05:39 PM

I already checked the power.  I spread the pin last night and I had 12.5 volts while it was slewing. I unscrewed the protective cover on my 12V to scope plug cord and checked the solder connections, all good. I don't believe power is the issue but thanks.



#7 rmollise

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Posted 25 March 2019 - 05:51 PM

I already checked the power.  I spread the pin last night and I had 12.5 volts while it was slewing. I unscrewed the protective cover on my 12V to scope plug cord and checked the solder connections, all good. I don't believe power is the issue but thanks.

But it was slewing again, then?

 

If it still slews in both axes, the problem isn't likely the motor control board (though it could be connections).


Edited by rmollise, 25 March 2019 - 05:52 PM.


#8 CJW8

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Posted 25 March 2019 - 06:14 PM

No it isn't doing anything.  the hand control is still blank.



#9 Jim Waters

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Posted 25 March 2019 - 06:17 PM

Check the HC cable.  If possible swap the HC and its cable with another user and retest.  


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#10 CJW8

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Posted 25 March 2019 - 09:37 PM

I have two options to test the hand control. 1.   I have a functioning hand control for a SLT Mount.  Can I reflash it to be a CGEM controller?   2.  Can I use my PC as a hand control to drive the mount?



#11 dfisherows

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Posted 25 March 2019 - 10:01 PM

The 2 HC are not exchangeable.  The PC would have to connect through the HC.  I would buy a new HC with the new mini USB connection.



#12 austin.grant

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Posted 26 March 2019 - 06:40 AM

Yes, you can typically reflash them into NXS (AltAz) or GEM mode, and it installs the accompanying software for all applicable mounts. I’ve flashed a couple of NexStar remotes from one type to the other with no issues.

Edited by austin.grant, 26 March 2019 - 06:40 AM.

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#13 rmollise

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Posted 26 March 2019 - 07:43 AM

I have two options to test the hand control. 1.   I have a functioning hand control for a SLT Mount.  Can I reflash it to be a CGEM controller?   2.  Can I use my PC as a hand control to drive the mount?

You can try it, but it's unlikely to help.

 

Best bet? Check your local astro club for a person experienced with Celestron mounts before you do anything else.


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#14 wrnchhead

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Posted 26 March 2019 - 07:48 AM

I kind of feel like the peanut gallery here, (Wow Uncle Rod himself is here lol) but I have felt the broken mount pain myself. I have the slightly older serial connected style hand controller and cable that came with a parts AVX I bought. If this is compatible, I'd be willing to let it go for $20 or something if it would help you out. 

 

I see them going in the classifieds all the time though, seems like about $35 instead of the $110 from Celestron directly. Kind of steep for something you may not need ultimately. 



#15 mclewis1

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Posted 26 March 2019 - 08:06 AM

Yes a hand controller that came off of an AVX can be used directly on a CGEM (it would however be a good idea to do a Factory Settings reset of the HC before using it). There would be no need to touch the firmware as both HCs would have the gem firmware (the revision levels might be different but that won't matter). There actually is no AVX or CGEM specific firmware, when a HC with the gem firmware powers up it checks the motor controller board in the mount to see what kind of hardware it's attached to. From that the HC firmware configures itself to whatever EQ mount it's on.

 

It's the same situation for a HC with the alt az firmware (the NXS type), these HCs can be swapped between alt az scopes. If however you need to cross mount types (alt az firmware HC used on a gem mount) then you need to re load the HC with the appropriate firmware.



#16 CJW8

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Posted 26 March 2019 - 12:20 PM

I kind of feel like the peanut gallery here, (Wow Uncle Rod himself is here lol) but I have felt the broken mount pain myself. I have the slightly older serial connected style hand controller and cable that came with a parts AVX I bought. If this is compatible, I'd be willing to let it go for $20 or something if it would help you out. 

 

I see them going in the classifieds all the time though, seems like about $35 instead of the $110 from Celestron directly. Kind of steep for something you may not need ultimately. 

I'd gladly buy for your HC.  How do we do the deal?  I can paypal you.



#17 wrnchhead

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Posted 26 March 2019 - 12:22 PM

That works. I will message you!



#18 wrnchhead

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Posted 31 March 2019 - 08:45 AM

CJ, am curious if you made any progress yet!

#19 CJW8

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Posted 31 March 2019 - 02:05 PM

I am fairly certain it is the Motor Control Board.  I plugged the hand controller into a different mount and it comes alive so I think the hand controller is ok.  I have located a motor board and am negotiating the purchase now.  Will inform thread when fixed.



#20 CJW8

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Posted 06 April 2019 - 01:05 AM

I got a replacement motor control board from a fellow CN member and now my hand control is working again.  Thanks to all!


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#21 wrnchhead

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Posted 06 April 2019 - 07:48 AM

Great CJ!


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