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CPC 800 azimuth motor only turns one direction

Celestron
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#1 Dgprof

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Posted 18 October 2020 - 01:42 PM

Hello. I have a Celestron CPC 800 that has suddenly stopped responding to the right direction key. The scope goes up and down (alt) and left but will not turn right. 
 

I’ve opened the cover to make sure all the cables are connected properly. I have good power supply. There doesn’t appear to be any smell of anything burned out inside. The azimuth motor responds at every motor speed, 1-9, when going left. It not right.  Otherwise everything works fine. I’ve done a factory reset but that didn’t help.

 

Any suggestions on what I should be looking for?

 

Thanks for your help. 
 

My controller firmware is: NXS 5.31.9200, MC 4.05


Edited by Dgprof, 18 October 2020 - 01:44 PM.


#2 junomike

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Posted 18 October 2020 - 03:18 PM

Does the Mount move right with the clutches off?  See if there's any resistance in that direction.

Aside from that, a replacement HC will let you know if it's the HC or not.



#3 Dgprof

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Posted 18 October 2020 - 03:37 PM

Hi Mike. The HC is relatively new and replaced last winter. I would need to get another one to see but I wouldn’t think it was that.

The mount turns freely when the clutch is released. 

 

I find it so odd because if it was the motor, you’d think it wouldn’t turn right or left...



#4 junomike

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Posted 18 October 2020 - 04:31 PM

Ya, ruling out the HC would be ideal however you'd need another or a WiFi (or Bluetooth) device to control it via the App.

Maybe someone will have an answer from previous experience(s).

 

Also, Welcome to CN!


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#5 mclewis1

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Posted 19 October 2020 - 02:39 PM

You could bypass the functionality of the physical hand controller by running CPWI (connected through the connection on the base of the HC).

 

It's possible but quite unlikely it's a firmware issue so I wouldn't at this time consider changing the firmware on either the hand controller or motor controllers.
 
The other troubleshooting step is to swap the Alt an AZ  motor connections on the motor controller board in the mount. If the problem moves to the other axis the problem is in the connector/cable or the motor controller board itself. If the problem doesn't move it's the motor/encoder assembly that's at fault.

 

More info on all of this is on www.nexstarsite.com


Edited by mclewis1, 19 October 2020 - 02:40 PM.


#6 Dgprof

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Posted 24 October 2020 - 01:20 PM

So I’ve managed to do the next step of swapping the Alt and AZ motor connections on the controller board. Now the Alt works in one direction only and the AZ goes both directions. So that confirms that the motors are fine. However, in both configurations, the right direction key does not respond. I also ran the controllers connected to both the base and the fork connections with same results.

 

Next I swapped out the Hand controller with an old one I had that works, even though it was acting a bit flaky when I replaced it. The motors responded in the same way while the right direction key (which always worked before on the old controller) does not respond. So I don’t think it is either a handcontroller or a firmware issue.

 

That leaves, I suppose, the controller board. I removed the board and looked for obvious signs of something burnt or a loose connection, but nothing was obvious. Am I missing anything?

 

Thanks for the good suggestions so far. Anything else I should do?

 

David


Edited by Dgprof, 24 October 2020 - 01:35 PM.


#7 jerr

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Posted 25 October 2020 - 02:35 AM

Hi David,

 

Keep us informed pls how this will develop.



#8 mclewis1

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Posted 25 October 2020 - 09:15 AM

David, 

 

That would pretty clearly mean that the problem is on the motor controller board. I would now do an MC firmware update. But before doing it I would review the info on www.nexstarsite.com about the problems with MC firmware updates and specific + hand controller firmware levels (basically you might need to do an HC update first).  

 

I doubt the firmware on the MC board is actually the problem but given the price of the replacement board it makes sense to make sure it isn't something strange with the firmware on your board.



#9 Dgprof

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Posted 26 October 2020 - 06:10 AM

Though it took a while to get the HC Update Software to work on my Windows 10 machine (little hint: make sure Java is installed and run it under WIndows 7 Compatibility), I did manage to do a reset of my HC Firmware, even though it already had the latest version already installed. I tested the controller and the same issue: Right Direction key doesn’t respond.

 

I haven’t yet done a MC Firmware update because I’m unsure of how to do that. I assume I’ll have to run a  serial to USB to phone jack cord to the scope from the computer, but wondering if that really will be necessary or can I just assume the MC board is the problem. 

 

Thanks for the ongoing help.

 

David



#10 jerr

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Posted 26 October 2020 - 06:28 AM

Hi David,

 

One thing that you most likely do not want are two MCs, both good. 

I would go for MC update first. It is a simple process if your computer has a serial port or if you have serial to usb adapter:

https://www.nexstars...pgradeHowTo.htm



#11 mclewis1

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Posted 26 October 2020 - 08:06 AM

David,

 

https://www.nexstars...pgradeHowTo.htm

 

It's the same connectivity you used to handle the hand controller updates through CFM so you won't need to add anything. Mike's warning from late 2019 is important but I believe it's been resolved, I just don't know the appropriate release levels (there is a difference between formally released firmware available through the CFM utility downloaded from Celestron.com and the newer beta firmware levels released through newer versions of CFM available from teamcelestron.com). 

 

Before going any further it would be good to get an update from Mike or others about what the appropriate hand controller firmware levels are right now so you can safely use the mcupdate.exe utility on your CPC.


Edited by mclewis1, 26 October 2020 - 08:06 AM.


#12 JayTheJack

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Posted 22 December 2020 - 06:37 PM

Hi, I'm a newbie here and created an account exclusively to know about this issue. I purchased an used CPC 800 and facing the exact issue. Were you able to resolve it OP? Thanks.

#13 Dgprof

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Posted 06 April 2021 - 10:55 AM

Hello, everyone. I wanted to update you all on this issue which has now been resolved.

 

I did all the software and firmware updates to no avail. So I finally ordered a replacement motor controller board.

 

I installed it and voila! Fixed. So it appears to have been the board all along.

 

One small glitch that I had to overcome was that the connector pins and plastic connectors were slightly different and so didn’t want to mate correctly. The plastic locking piece to hold it in place on the board wasn’t fully compatible and the cables were in danger of working themselves free (and did during testing). So though I didn’t exactly want to do it, I put a dab of Gorilla glue on the outside plastic (being careful not to get on the pins themselves) to ensure the cable and board side stayed together. I may regret that in 10 years when I have to undo them again, but I think they will be easily separated if need be. (Sorry, I should have taken pictures but had reassembled already and didn’t want to take it apart again!)

 

Otherwise, is working fine. Resolved.


Edited by Dgprof, 06 April 2021 - 10:56 AM.


#14 Dgprof

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Posted 20 June 2021 - 08:48 AM

Update #2: The cloud cover here in Ottawa has been so persistent that I’ve barely had a chance to test the CPC800 upgrade. The bad news is that in my last two outings, I have come across a brand new problem. 

 

The short version is that no matter what I do, after alignment the star or object drifts up and to the left at a fairly rapid rate. Within 30 secs it is out of view. I’ve tried:

1) Both EQ-North and Alt-Az modes.

2) Re-polar aligned several times

3) removed any additional items to ensure balance is correct.

4) repeatedly ensured time and location was correct.

5) Did factory reset on handset

 

etc.

 

When using the directions keys, I can maintain the object in perfect centre by hitting the right direction key ever second or so. I never have to hit a different key. It is almost as if RA motor is running either a bit too fast or too slow. (I used the star diagonal with my eyepieces).

 

Any tips on what to look for would be appreciated.


Edited by Dgprof, 20 June 2021 - 08:49 AM.


#15 Lola Bruce

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Posted 20 June 2021 - 09:54 AM

Older Celestrons are somewhat know for connector corrosion. Pull the covers off and carefully one at a time pull the connectors off and on a few times. You will see this polishes the pins in the contact area. Make sure every thing is off and battery disconnected before starting. Worked for me.



#16 rmollise

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Posted 20 June 2021 - 02:28 PM

So I’ve managed to do the next step of swapping the Alt and AZ motor connections on the controller board. Now the Alt works in one direction only and the AZ goes both directions. So that confirms that the motors are fine. However, in both configurations, the right direction key does not respond. I also ran the controllers connected to both the base and the fork connections with same results.

 

Next I swapped out the Hand controller with an old one I had that works, even though it was acting a bit flaky when I replaced it. The motors responded in the same way while the right direction key (which always worked before on the old controller) does not respond. So I don’t think it is either a handcontroller or a firmware issue.

 

That leaves, I suppose, the controller board. I removed the board and looked for obvious signs of something burnt or a loose connection, but nothing was obvious. Am I missing anything?

 

Thanks for the good suggestions so far. Anything else I should do?

 

David

You're not missing anything, since azimuth works fine with the cables swapped. However, I'd hit the connectors involved with azimuth with Deoxit before thinking about a new board!


Edited by rmollise, 20 June 2021 - 02:29 PM.


#17 scottkauffman

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Posted 20 July 2021 - 07:57 AM

I'm having a very similar problem with my new CPC 800, which I have had for less than a month.  I am concerned the Az motor is not working.  The motor worked on the first two outings.  Both my Nexstar and Starsense hand controllers have been updated to the latest firmware.  

 

I started the night using CPWI with the Starsense hand controller.  Upon startup, the Alt motor went north to Polaris but then hung up.  I thought that it was due to sky haze and difficulty finding stars, but after 20 minutes, I turned everything off, disconnected and started again. This happened twice more.  

 

I then disconnected the Starsense controller and camera, turned everything off,  and tried using CPWI with the Nexstar hand controller. Again, no luck with Az.  

 

I then disconnected everything and restarted with just the Nexstar hand controller.  Alt worked fine.  Az didn't work.  

 

I checked to make certain the Az clutch was tightened.  It was.  I then loosened the Az clutch and confirmed I had free movement in both directions.  

 

I set the mount up in my living room this morning using the Nexstar hand controller, and same result.  Alt works fine; no Az movement or noise.  

 

The only thing I can think of is that as I put the mount on the tripod at the beginning of the evening, there was some resistance while I spun the mount to set the mount on the mounting bolts.  However, the mount was moving freely before I started the above process.  



#18 scottkauffman

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Posted 20 July 2021 - 01:13 PM

After reading this thread, I unscrewed the plate covering the circuit board and checked the connections.  Still no Az.  

 

I disconnected the Az and Alt connectors and reversed them.  Powered back up and they BOTH worked.

 

Put back the connectors in the correct position.  Both worked.  It appears there was a loose or slightly corroded connection somewhere.  Put everything back in place and Alt and Az both still work.  

 

... now just waiting for the smoke to clear.  




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