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Buying advice for a Celestron CG5-GT mount.


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So I'm looking at an ad for a used Celestron CG-5 AS-GT computerized mount and the price is VERY good, but I'm just concerned that it's for a problem that will put me down a tough road. The ad indicates that the price is so low due to:

"an error code that says the hand controller has lost communication with one of the drives on the mount. I think it is the declination axis, because the mount slews non-stop in declination when I try to do a polar alignment."

My question is will this mount be a money pit? I am tech savvy and I have a fair grasp of electronics but are these mounts generally serviceable by an individual or am I going to end up having to send it in to Celestron at my expense?

Realistically speaking I don't have a budget for a new mount but if I don't go with this mount I'll probably save up money for another year and get the Celestron Advanced VX mount.

What should I do?

Thanks so much,

Mitch

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I had a similar problem with my CG5. It was a faulty Dec cable, very easily fixed with a crimper. It's most likely that's the problem with the one you're looking at. If the handset is giving an error code (error 17, if I recall right), and if the mount's motors function at all, that suggests there's a problem neither with the handset nor motors. The external Dec port cable is one of the CG5's vulnerable points. A cable test and repair kit (like this: -click-) will be handy if you don't have one.

Please note that I said "most likely", and "suggests". I can't be certain, but going on my experience, that mount sounds worth it. I hope that this fault is the reason for selling at a good price, rather than for selling it at all.

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Ah. That's an important update! I was, perhaps mistakenly, under the impression that the seller wasn't the sort of person to tinker with technology. My initial assessment is now on more shaky ground!

Adding a polarscope is a good thing - they cost something in the region of $60.

"a new main computer"??? I recommend finding out exactly what that means. A new handset (that's the only thing which could nearly be called a "computer"), or a new motor control board?

"and a brand-new right ascension motor assembly." Like the, ahem, main computer, I wonder why it needed replacing?

I'd certainly have a good close look at it before purchasing - make sure it turns smoothly on all axes, so that at least the main mechanics are sound. It sounds to me like he may have overloaded the mount. Or that he's not very good either at diagnosing problems or at describing an item he's trying to sell. The fact that he mentions at all the RA motor and the polarscope suggest that at least it's not stolen, but from your quote, I feel he doesn't quite know what he's talking about! Doesn't fill me with confidence, but at that price ...

... and it could still be simply that the Dec cable needs fixing!

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Yeah, I agree. Very likely a repair job that he didn't understand.

But even so, I wouldn't dismiss it! That's such a good price, if you couldn't fix it yourself, no doubt you could resell it for a profit, even in the state it's in. As long as the mechanics are sound, of course.

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My DEC drive on my CG5 GT stopped working recently.  I was prepared for a lot of pain both financially and timewise, but it was all sorted with a replacement DEC drive motor assembly for about $60 in less than a week.  The internal electronics of the mount are very modular and easily replaceable.  However if it is a handset problem then that might be expensive.

An easy diagnosis is to swap the DEC/RA motor connector cables round as the drive circuits are the same and from this you can eliminate components.

From memory I think there are 3 electronics boards, two of them being fairly "simple" and one more complicated but from what I remember nothing scary, no horrendous densely packed surface mount stuff. Then there are the two drives, the DEC drive I found easy to replace. I didn't look at the RA drive as it was working!

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I've had two of the CG5GT Goto mounts (and a manual one to which I added tracking motors) and I have to say the guidance given by Squagnut is excellent, and for the superb price it's a very good punt that I would take anytime.

So long as you regard it as a potential "project" mount that might need a little tinker with - you can't go wrong. If at worst it all fails on the electronics side - you can strip the motors off and ditch the handset then sell it on as a manual mount - you'll get $100 - $150 back for it easily.

On the other hand if it's just - a small crimp here - or a new dec motor there - to fix it, you'll come out with super goto mount that has been a standard "first imaging mount" for years - at an absolute bargain price.

It's a no brainer from what I can tell by your description. Hope that helps and good luck. :)

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Thanks for all your excellent advice, it sounds like I might have inadvertently troubleshooted the problem for him and now it seems like he's more interested in fixing it himself, he might turn around and try to get twice his asking price which would be really shady of him, but he might turn around and say "well I put this much money into fixing it, can we maybe meet halfway" and I'd be down with that. I'll post an update in a little bit with how I made out. Thanks again, you guys are awesome!

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Glad to help! I'd say that if your questions have helped him, he owes you something back for that. But that's a matter for your diplomacy. Good luck!

If you buy it, please post pictures on here - I'm sure more advice will come.

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UPDATE 02/14: The seller completed a "drive swap" and determined that the dec drive assembly needed replacing, quoting me $165. He's going to fix it and then allow me first crack at it with an "adjusted price" Don't really know what that means but all things considered what should I be offering him for this mount based on its "history?"

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Ok. Not ideal! I can't comment on the price he quoted for the replacement drive assembly - as I understand it, you can get spares directly from Celestron, but they don't publish a price list. You contact the support dept and they give you a quote for the parts you want. Gcek above says he got a replacement dec drive for about $60.

I should have advised you not to ask questions, just buy the thing and post pics on here so we could help get it going!

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If he's fixing it to that extent then I would be glad I hadn't bought it and give it a wide berth if I were you. His new price is gonna make it not worth going for one that didn't need fixing.

My advice - look around for a good condition one in working order with nothing more than cosmetic issues if any at all. :)

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Yup - I wouldn't entertain a guy like this - sounds to me like he's messing you about. Anyone selling genuinely would have closed the deal by now without changing the goalposts every few mins.

If he won't accept the original price for it as advertised, I think you're best advised to walk away from the deal. There's always another one around the corner. :)

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Hey Mitch,

 Sorry to here you are having trouble with your  set-up. Have you or are you able to upgrade to a better go-to Mount? My wife and had the same go-to mount as you do. I had out Celestron 6" refractor on it, also I would piggy-back our Stellarvue 80mm Nighthawk on the Celestron. I didn't like the mount or the keypad and software very much. I wasn't to fond of the C-GT 5 go to mount. About 1 year ago we upgraded to a Orion Atlas EQ-G mount. By the time you attach 2 scopes, a Canon T2i camera and a finder 10x60 finder and the counterweights, there is a lot of weight on the mount. So I didn't feel that the Celestron mount was able to support all of that weight. The Software/firmware is a lot better then the Celestron set up from my experience. The Orion mount is also pretty quiet compared to the C5 -GT mount we had. I would also recommend the Orion Sirius EQ-G mount. Same software, just a smaller mount. We are happy with our mount, the GO-TO is very quiet and is accurate, goes to the object every time when looking in the eyepieces.

Clear Skies,

Marc 

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If you can do that, then do it. I have an extra handcontroller for my CG5 GT you can borrow to check if it is that, that's faulty (and if you beg nicely, I can be persuated to lend you other parts  :grin: ). Anyway,just the tripod alone is worth the money, the legs are same size as the ones on an EQ6 pro, and much better than on a EQ5 pro, I know, I have all 3 mounts.

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I decided to walk away. I had to be honest with myself and if I got myself into a frustrating situation with the mount and everything, it could have pushed me away from astronomy all together. Thanks for all your support guys, when I do decide to buy something I'm glad I have such a fantastic support group to help me along. :)

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