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Equipment Discussions >> Mounts

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Agnosticus
Pooh-Bah


Reged: 09/12/04

Loc: 43N, 89W, Earth
CG-5 Goto mount problem...
      #3741353 - 04/12/10 08:46 PM

Hi everyone,

For whatever reason, my used (but newly purchased) Celestron CG-5 GOTO mount is acting like it's possessed. When I turn it on, put in all the requisite info, and start the automatic 2-star alignment, it ends up slewing...and slewing...and slewing, until it's pointed at the ground. Then it keeps intermittent little movements indefinitely (until I end up having to switch it off). Any ides?


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hfjacinto
I think he's got it!
*****

Reged: 01/12/09

Loc: Land of clouds and LP
Re: CG-5 Goto mount problem... new [Re: Agnosticus]
      #3741363 - 04/12/10 08:51 PM

I never had this issue, but I have had slew speed up or slow down. Check the battery connection, it might be loose. I usually use a knife to pry apart the connection and that seems to always help.

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jfusto
journeyman


Reged: 09/24/08

Re: CG-5 Goto mount problem... new [Re: hfjacinto]
      #3741372 - 04/12/10 08:59 PM

Are you polar aligned before you start the 2-star alignment procedure?

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RTLR 12
Post Laureate
*****

Reged: 12/04/08

Loc: The Great Pacific NorthWest
Re: CG-5 Goto mount problem... new [Re: jfusto]
      #3741392 - 04/12/10 09:09 PM

Sounds like a power issue. Check your power supply, cables and connections. You will also need to do a factory reset and re-enter your info and settings.

Stan


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Agnosticus
Pooh-Bah


Reged: 09/12/04

Loc: 43N, 89W, Earth
Re: CG-5 Goto mount problem... new [Re: RTLR 12]
      #3741579 - 04/12/10 10:57 PM

Yep, polar aligned. It seems to be powering up OK (using their cig lighter car adapter), though perhaps the connection needs to be cleaned. I will try the factory reset as well. Thanks!

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Fred1
Carpal Tunnel
*****

Reged: 09/19/07

Loc: Somewhere in the Orion Spur
Re: CG-5 Goto mount problem... new [Re: Agnosticus]
      #3741583 - 04/12/10 11:01 PM

Are you sure you're getting at least 11-12V from your power supply?

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RTLR 12
Post Laureate
*****

Reged: 12/04/08

Loc: The Great Pacific NorthWest
Re: CG-5 Goto mount problem... new [Re: Fred1]
      #3741602 - 04/12/10 11:12 PM

You had better make that 12-13V. At 11 volts you will have problems...

Stan


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Chris Rowland
professor emeritus


Reged: 02/28/05

Re: CG-5 Goto mount problem... new [Re: RTLR 12]
      #3741874 - 04/13/10 03:41 AM

If the power and factory reset solutions don't work then it could be a problem with the connections to the motors. If the encoder signals are bad the controllers don't know what the motors are doing and tend to keep driving them.

Check all the cables and connectors to the motors, inside and out. It may help to push the cables a bit further into the IDC connectors.

Chris


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guyinthesky
professor emeritus


Reged: 04/13/07

Loc: western ma.
Re: CG-5 Goto mount problem... new [Re: Chris Rowland]
      #3742036 - 04/13/10 07:33 AM

if the car is not running its only getting 12 volts, try it with it running, 13.8 volts.

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Agnosticus
Pooh-Bah


Reged: 09/12/04

Loc: 43N, 89W, Earth
Re: CG-5 Goto mount problem... new [Re: guyinthesky]
      #3742040 - 04/13/10 07:38 AM

Great suggestions. I will try them and get back.

Thanks again, gang!


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Javier
Carpal Tunnel
*****

Reged: 05/03/09

Loc: New Jersey
Re: CG-5 Goto mount problem... new [Re: Agnosticus]
      #3742051 - 04/13/10 07:50 AM

Kevin,

This sounds like a power issue. Does the display on the hand controller glow a steady red color or does it sort of fade in and out? I learned that the CG-5 and probably all Go-to mounts are very sensitive to power fluctuations.


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Agnosticus
Pooh-Bah


Reged: 09/12/04

Loc: 43N, 89W, Earth
Re: CG-5 Goto mount problem... new [Re: Javier]
      #3742236 - 04/13/10 09:56 AM

The illumination seems to be pretty consistent.

One other question: with what do you clean the connections? A q-tip will no doubt snag on the little prongs in the cables and the jacks. Use a little brush? Dampen it in alcohol?


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Eddgie
Postmaster
*****

Reged: 02/01/06

Re: CG-5 Goto mount problem... new [Re: Agnosticus]
      #3742568 - 04/13/10 12:55 PM

I don't think it is a power problem. If the power is interruped even for the briefiest instant, the hand controller will reset and you would have to go though the setup again.

I have heard reports that some power supplies with noize will cause problems, but there should be a ferrite core on the power cable (maybe Inch long, half inch diameter plastic housing on the power cable). The role of the ferrite core is to suppress noise and spikes on the power signal.

Still, it is impossiblet rule this out, so the easiest thing to do us plug it into a car cigerette lighter.

Otherwise, I think you have a problem either inside the mount (which I think is unlkely) or with the connections inside the RJ jacks on the mount.

I have had this problem with 3 different mounts in the past. Two were LXD-55s, and one was with a CG5.

The RJ ethernet/Telephone type jack on the housing has tinly little springy metal fingers that press against the pin on the end of the plug on the handset cable. I think that if these loose tension or get any corrosion on them, the signal can be interrupted or corrupted.

I have used a very tiny spring hook tool to pry under these spring contacts and VERY VERY gently "Form" them back up a bit and this has cured intermitttent problesm on these three mounts AND on my CGE, which used to somethimes have runaways.

I don't think it is as likley that there is a problem inside the housing. It couldbe though, and if reseating the dec and RA cables severla times to wipe the contacts (they are self wiping and unplugging and re-plugging can acutally wipe off slight corrosion) or re-arching the springs contacts doesn't work, then it may be necessary to open the housings and reseat the internal plughs, but again, I think this is not a likely cause of the problem.

Contamination on the face of the emmitter disk can cause pointing errors, but the Calibration proceedure I think attemtps to account for a blocked emmitter disk windows.

Your problem sounds more to me like signal distortion.

Good luck.


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rmollise
Postmaster
*****

Reged: 07/06/07

Re: CG-5 Goto mount problem... new [Re: Agnosticus]
      #3743227 - 04/13/10 05:58 PM

Quote:

Hi everyone,

For whatever reason, my used (but newly purchased) Celestron CG-5 GOTO mount is acting like it's possessed. When I turn it on, put in all the requisite info, and start the automatic 2-star alignment, it ends up slewing...and slewing...and slewing, until it's pointed at the ground. Then it keeps intermittent little movements indefinitely (until I end up having to switch it off). Any ides?




This is symptomatic of poor power. First step in troubleshooting is to try an alternate power source, preferably a fully charged battery not resident in an automobile.


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Agnosticus
Pooh-Bah


Reged: 09/12/04

Loc: 43N, 89W, Earth
Re: CG-5 Goto mount problem... new [Re: rmollise]
      #3743719 - 04/13/10 10:31 PM

Not the power... I made sure of that tonight. I also opened up the housing and ensured the connectors were well seated. I didn't open the DEC housing yet, though. I also haven't cleaned the controller or other jacks yet since I have no contact cleaner. Nor have I tried to gently pry up the connector prongs.

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Agnosticus
Pooh-Bah


Reged: 09/12/04

Loc: 43N, 89W, Earth
Re: CG-5 Goto mount problem... new [Re: Agnosticus]
      #3743725 - 04/13/10 10:35 PM

I should also add: If I turn the thing on, if I don't do anything at all for long enough, it will just start slewing on it's own. I hope I don't have to ship this to Celestron. It's not under warranty anymore.

Edited by Agnosticus (04/13/10 10:36 PM)


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Agnosticus
Pooh-Bah


Reged: 09/12/04

Loc: 43N, 89W, Earth
Re: CG-5 Goto mount problem... new [Re: Agnosticus]
      #3743759 - 04/13/10 10:51 PM

One last (probably very relevant) detail. When I do my 2 star alignment, I tell it to go to Capella first (since it's fairly high in the sky). It goes approximately to where Capella is, but the little spinny icon in the hand control screen just keeps spinning... then the 'scope proceeds to slew around and point at the ground. Then it will just stop for awhile... scoot a little... stope awhile..etc... It goes through this same process every time.

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rmollise
Postmaster
*****

Reged: 07/06/07

Re: CG-5 Goto mount problem... new [Re: Agnosticus]
      #3744191 - 04/14/10 08:07 AM

Quote:

Not the power... I made sure of that tonight.




How did you make sure of that? It sure _sounds_ like power problems. Failing that, your best course is "Call Celestron."


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Fred1
Carpal Tunnel
*****

Reged: 09/19/07

Loc: Somewhere in the Orion Spur
Re: CG-5 Goto mount problem... new [Re: rmollise]
      #3744819 - 04/14/10 02:06 PM

Perhaps the power switch is corroded and not making good contact. Doesn't cost much to replace one. I'm pretty sure this is the one, if you decide to go that route.

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dwitek
sage
*****

Reged: 07/03/08

Loc: White Lake, Michigan
Re: CG-5 Goto mount problem... new [Re: Fred1]
      #3745495 - 04/14/10 08:12 PM

Just yesterday I received a used CG-5 and mine does the EXACT same thing. It slews close to where the first alignment star should be (it's still daylight), stops for about 10 seconds but the "working" Icon keeps spinning. Then, the scope starts slewing, in dec only, for about half a revolution. Then, it pulses in the same direction until the dec cord wraps itself around the housing and I have to stop it or else it will rip the cord apart.

I checked the raw voltage from the power supply and it shows 15.2 volts. But, this is without a load.

I've reset to factory defaults but I understand that there are some values that don't get reset. The reset command only resets values stored in the hand controller, not the mount itself.

This is my first Celestron equipment and I know everyone raves about this mount but I'm quite disgusted.

I will add that the person that sold the mount to me forgot to send the factory Dec motor cord so I made one myself. It is flat, 6 wire telephone cable with the proper ends for 6 wire but is not shielded. I only mention that because I was reading that the CGEM uses a shielded cable but I could not find any info on the specs of the CG-5. The seller is sending me the factory cord but it's clear tonight so I made my own.

ADD 20:37: I notice that the RATE key changes the slew rate in RA but Dec stays at maximum speed no matter the setting. Is this normal? Could it be related to the homemade cable?

Edited by dwitek (04/14/10 08:35 PM)


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Eddgie
Postmaster
*****

Reged: 02/01/06

Re: CG-5 Goto mount problem... new [Re: dwitek]
      #3745569 - 04/14/10 09:14 PM

I don't think these cables should be flat. They should be twisted pair. The twist in a data cable greatly reduces interference from outside sources.

And again, any intermittent connection I think will cause most of the symptoms mentioned in the OPs post and your own.
You may want to check the contacts in the RJ jacks. De-ox maybe.. I don't know. I fixed mine by gently forming up the spring contacts inside the RJ plugs on the mount.

Of course you problem cold be totally different than the problem I had, but I had it with 3 different mounts and was able to improve operation just by doing the above.

I have to confess though that it doesn't even make sense to me. The RJ Jack was invented by the phone company to be hyper-reliable and it is a brilliant design.

And yet I have had LXD and CG5s and my CGE all experience run-aways, and cleaning the contacts and reforming the spring contacts seems to have elminated the problem ever time.

Anyway, could be someting else entirely.

Regards.


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dwitek
sage
*****

Reged: 07/03/08

Loc: White Lake, Michigan
Re: CG-5 Goto mount problem... new [Re: Eddgie]
      #3745600 - 04/14/10 09:53 PM

Update on mine:

I swapped the motors from RA and Dec and the problem moved with the motor. Now the RA does the exact same thing and the Dec motor stops where it should. It looks like, at this point, that a new motor is in order. I've not looked into this particualr motor before but I'm going to check to see if there is an issue I can spot inside the cover on the back. Maybe the encoder is covered or loose. On my LX200 you can see the encoder but this is more sealed.

Will update in a little while.


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jrcrillyAdministrator
Refractor wienie no more
*****

Reged: 04/30/03

Loc: NE Ohio
Re: CG-5 Goto mount problem... new [Re: dwitek]
      #3745609 - 04/14/10 10:00 PM

Quote:

On my LX200 you can see the encoder but this is more sealed.

Will update in a little while.




The back cover snaps off and reveals the encoder wheel.


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dwitek
sage
*****

Reged: 07/03/08

Loc: White Lake, Michigan
Re: CG-5 Goto mount problem... new [Re: jrcrilly]
      #3745635 - 04/14/10 10:18 PM

There is nothing obviously bad about the encoder. It had some grease on it so I cleaned it off but it acts the same. I adjusted it very close then far away from the LEDs and that didn't change anything.

I mentioned that changing the slew rate only effected the RA. Since the motor swap that problem has also moved so it HAS to be an internal motor issue. I will order one from Celestron unless someone has a better, and/or quicker, source for it.

Agnosticus, you may want to try the motor swap and see if the problem moves with it.


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rmollise
Postmaster
*****

Reged: 07/06/07

Re: CG-5 Goto mount problem... new [Re: dwitek]
      #3746099 - 04/15/10 07:39 AM

Quote:

Just yesterday I received a used CG-5 and mine does the EXACT same thing. It slews close to where the first alignment star should be (it's still daylight), stops for about 10 seconds but the "working" Icon keeps spinning. Then, the scope starts slewing, in dec only, for about half a revolution. Then, it pulses in the same direction until the dec cord wraps itself around the housing and I have to stop it or else it will rip the cord apart.






Well, your problem is in declination, and you replaced the declination cable, so _I'M_ thinkin' that might just be a suspect.


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Agnosticus
Pooh-Bah


Reged: 09/12/04

Loc: 43N, 89W, Earth
Re: CG-5 Goto mount problem... new [Re: rmollise]
      #3746117 - 04/15/10 08:02 AM

Hi Dave,

Thanks for your report! I will swap out the motors and see if that's it for me too. Obviously if the DEC problem switches to your RA when you switch the motors, your homemade cable is not the cause. Neither must it be in the electronic boards. It simply must be somewhere in the motor/encoder. I'm wondering if I should hang on to mine (the seller and I are talking about refund) until you get your motor and install it to see if that's the fix you need.

Thanks again... and your description of the slewing problem (much better than mine) is absolutely exactly what mine does, so it must be some kind of problem that fairly common.

PS -- to answer Rod, I used the car DC adapter (and started my car) to ensure enough power was getting to the 'scope. It was running at least 13v and plenty of amperage. Because of the consistent behavior of this problem, it just doesn't seem like a power issue anyway.

Edited by Agnosticus (04/15/10 08:03 AM)


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dwitek
sage
*****

Reged: 07/03/08

Loc: White Lake, Michigan
Re: CG-5 Goto mount problem... new [Re: Agnosticus]
      #3746403 - 04/15/10 10:43 AM

I have an email into Celestron to get a price for the motor. I will post their response when I get one. If I don't hear from them by mid-afternoon I will call them later today. They responded the next day when I asked about the cost for a new cable Wednesday night.

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dwitek
sage
*****

Reged: 07/03/08

Loc: White Lake, Michigan
Re: CG-5 Goto mount problem... new [Re: dwitek]
      #3746544 - 04/15/10 11:45 AM

Here is Celestron's response for the new drive motor. I will write them a check tonight and mail it tommorrow.

The part number is #CG5-F00-1 and is available for $28 plus $5 for shipping and handling.
To order, please send a check or money order, along with your part request to:
Celestron
P.O. Box 80770
San Marino, CA 91118
Attn: Parts Please make sure we have your correct mailing address and contat phone number. Please note this must be a U.S. or Canadian return ship to address and all parts requests are non-refundable.
**Note** California customers MUST add 9.75% sales tax to their order, exclusive of shipping costs.
Delivery time varies. On average parts orders can take 2-4 weeks, depending on availability. Please allow a minimum of 2 weeks prior to checking status of your part order.

Clear skies,

Celestron Technical Support


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Agnosticus
Pooh-Bah


Reged: 09/12/04

Loc: 43N, 89W, Earth
Re: CG-5 Goto mount problem... new [Re: dwitek]
      #3746861 - 04/15/10 01:49 PM

Hi Dave,

Yep, I called (and actually got through!) this morning and got the same info. Pretty cheap, really. Less than I expected. I think I'm going to go ahead and order one too. Thanks again for your investigations!

Kevin


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dwitek
sage
*****

Reged: 07/03/08

Loc: White Lake, Michigan
Re: CG-5 Goto mount problem... new [Re: Agnosticus]
      #3784154 - 05/03/10 05:18 PM

FOLLOWUP:

The new motors fixed both my and Agnosticus' issue with our mounts.


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