Costly error Celestron CG5 Advanced GT
Posted 22 February 2014 - 11:45 AM
Posted 22 February 2014 - 11:57 AM
I would think the problem lies with the MC board. You can swap the connectors for the motors on the MC board and seee if this changes anything, but you put 12v of power where it shouldn't have been. I don't know why they don'y protect the boards better, but they don't. Wouldn't cost that much to do.
Posted 22 February 2014 - 12:27 PM
You don't think it would be the DEC motor board. Also, are you saying I can move the plug on the main board to a different position like for the AUX port. Sorry but I am a baby when it comes to these mounts. If only it were a car. I know what you mean about protecting the boards, then again I could have payed closer attention to those cables!
Posted 22 February 2014 - 01:48 PM
There is a possibility that it could be an encoder problem, which means you have to replace the motor. (Unless you are really good at electronics, then you can just replace the encoder) There is no DEC motor board. There is only 1 board in the CG-5 mount. The MC board has all of the electronics for the mount. On the MC board there are 4 plug-in connections. They are marked "ALT", "AZM", "SBB", and "AG". You want to swap the ALT and AZM connections. These correspond to the motors. (AZM = RA and ALT = DEC)
Posted 10 February 2015 - 11:10 AM
Gents: I did the exact same thing last night. Rather than send the mount head and hand control back to Celestron, can you tell me what the fix was. I can order new parts and fix it quicker myself if I can determine what I need. Thanks, Don
Posted 10 February 2015 - 11:24 AM
I did the same thing and the result was the encoder needed fixing.
Posted 10 February 2015 - 03:34 PM
Thanks -- did you send it to Celestron, get a new motor (assume it was the Dec motor), or repair the encoder yourself?
Posted 10 February 2015 - 08:51 PM
The motor should only get 12Vdc from the driver on the MCB. The encoder needs 5V and I doubt it can handle reversed polarity and 12V will surely kill it. I have seen reversed polarity blow the driver on the MCB. Here's the wiring of the connector panel.
Posted 10 February 2015 - 09:06 PM
So I probably have a blown MCB and Dec encoder... Are there any repair services out there for the encoder, or is it time to order a new motor/encoder from Celestron? Thanks.
Posted 11 February 2015 - 06:24 PM
Posted 12 February 2015 - 09:49 PM
I did this same thing 16 months ago. Fortunately my stepbrother has a CG5 and we experimented by using each of his components in mine. It ended being the motor control board AND the DEC motor. I took a break from astronomy until 2 weeks ago and finally ordered the parts ($247.00 from Celestron including shipping). Everything is working fine with the exception of the above mentioned backlash issue.
Posted 13 February 2015 - 01:01 PM
I haven't seen the circuit for the cg5. I'm a ham operator for 35 years and worked for DOD doibg component level prototyping and integration. If you want to take a chance waisting time , open up the cases and look for the closest IC to where you plugged the power wrongly into. More then likely it was looking for something like 5 volts and you gave it 12. If it was reverse polarity protected there will be a black cylinder looking thing with a strip around one end, a diode. If not and it goes directly to an IC like ac8 or 16 pin job, you more then likely HOPEFULLY just smoked the initial latching type IC to put it in layman terms. Call it an addressing chip that turns thibgs on and off by supplying positive output power or completing a circuit to ground energizing a circuit. I've never looked at a goro mount but have built several servo control boards for satelite control dish boards for pretty precise tracking of rapidly moving objects. If your lucky you wil be able to see a burn mark at the input of one of the oins to the chip. Just flying blind here. I hate when companies won't swap out a 2 $ ic and rather just swap out and charge you for a whole new board. If you can find a burn chip hopefully it blew fast enough to not take other stuff down the line with it. You can read the number off the chip and Google it. The best and cheapest place to buy components is a place called Mauser or dig ikey. Radio shack for a 15 watt soldering iron, 6 bucks for solder and some steady hands and you may get lucky. Like I said just flying blind.,if you feel compelled after being able to visually see something smoked, and you can actually just take a sniff, if it smoked you will smell it, you can photo the board and send it to me and I might be able to identify how they are doing things and tell you what you need.,if it is diode protected I can tell you how to bypass it and get it working immediateky. But if you do it again you probably will cascade the entire circuit to oblivion ha ha ha. Normally I would stay out of it since I'm flying blind but I read 248 bucks or something, that mighht hurt. My email is clustersurviver@ yahoo. Com. If it's a counter type chip or regulator or something simple I probably have it and WOUZlD send you one. You wanna kinda look for something like 317 or 74- or 12 or 05 or a polarized round blue and white capacitor if these things are hardened against spurious rf hash. They are I believe part 15 devices and must accept harmful interference because they have timing circuits in them that generate radio frequencies. If not just ignore me ha hsha . Just start by smelling it, there will be no mistaking it!
Posted 13 February 2015 - 01:08 PM
I just looked at the board picture seen above. It IS reverse polarity protected, BUT I don't think you reversed the polarity. You may have fed straight power to the declination( was it I forget) board which probably either looks for a low signal or positive 65 vokts not the 12 you may have given it. If that's the case based on the other fellows parts cost you may have blown the stepper control and motor power supply and maybe blew the windings on the motor. All easy to check with ac10 dollar meter. Looks like a simple circuit.
Posted 13 February 2015 - 01:11 PM
now if you put 12 vokts INTO the logic circuit of the handbox then you stand the chance of nuclear fusion.... These darn things are so cheap but we want our price points..... At least Celestron will sell you the parts meade won't even talk to you
Posted 17 February 2015 - 02:32 PM
Thanks for the input. My stepbrother is working on repairing an oscilloscope that was given to him. Once he gets it working he's going to go through the motor control board to see if it's fixable. If so we'll have a backup between us. I don't hold out hope for the DEC motor.
Posted 20 February 2015 - 06:44 AM
Well, I got a new MCB and Dec motor from Celestron and put them in the mount. Powered up and the hand controller showed no errors. Even though daytime, I tried a two-star alignment, and the correct stars showed up -- Vega and Altair for the time of day. I slewed and here's where it goes bad -- I had slew movement in RA only, and nothing in Dec. I tried using the hand controller keys to slew in Dec and again, nothing. So, now I question whether I received a bad motor or whether for some reason no power is getting to it. I'm going to try to see if there is any voltage getting to the Dec board later today, using a multimeter. I did notice that the motor provided by Celestron had a different metal bracket. I simply removed the motor from the bracket and installed it on the old one in the mount. I also noted the wires came out of the motor differently, but the connector was a good fit for the Dec board (which I also replaced). I'm baffled at this point.
Posted 20 February 2015 - 07:17 PM
Thanks -- all appear good, although I ordered an RJ12 cable tester to check the Dec cable. Tried two different hand controllers and two different Dec boards with same results. Working with Celestron to return the motor, since I really cannot figure out what else it could be. I figure it less likely that I got a bad replacement MCB, but who knows.
Posted 20 February 2015 - 10:21 PM
Considering some of these crummy wall-plug DC power supplies can have voltage swings as wide as 50%, there should be protection in these mounts. Or they should used keyed plugs, something. Some mount design is from the electronic Dark Ages. I remember one Chinese mount that had a thin circuit boad with a phone jack on it, with no protection at all, it just stuck out in mid-air! Another mount design inteferred with the RA and DEC plugs when it was orientated a certain way. The engineers who work on some of these are bottom-barrel or, they are being forced to work to unrealistic cost levels.
Edited by RichA, 20 February 2015 - 10:22 PM.
Posted 21 February 2015 - 01:35 PM
I did notice that the motor provided by Celestron had a different metal bracket. I simply removed the motor from the bracket and installed it on the old one in the mount. I also noted the wires came out of the motor differently, but the connector was a good fit for the Dec board (which I also replaced). I'm baffled at this point.
I'm guessing that's the problem. My new DEC motor was exactly as the one that came out, I didn't even need to adjust the alignment with the gear wheel. Hopefully when you get the right motor you'll be back in action.
Posted 21 February 2015 - 04:46 PM
Aha -- thanks very much for that key info! The Dec motor I was sent had the wiring harness on the opposite side, used three hex vice flat-head phillips screws, and had a metal bracket that was completely different. While the motor assembly itself was very similar, these differences made me suspicious. I did compare it with the RA motor to see if the RA vice Dec motor was sent, but it didn't match that one either. So, we'll see what I get sent back from Celestron -- which will be another two-weeks given the return process.
Posted 09 November 2016 - 10:39 AM
The AUX port or the Autoguide port?
The AUX ports are the same and the hand controller port and are safe to use as an alternate for the hand controller connection. If it's just a situation of moving the hand controller between the hand controller port and the AUX port and the AUX port doesn't work then it could just be a failure of the power board (picture of it in an earlier post above) but it's more likely to just be a problem with the connectors. A little contact cleaner on the pins or careful use of a Qtip and some alcohol will often clear up any intermittent issues. You might also take a close look at the pin in the AUX port connector as these can sometimes but damaged and bent a little bit.
If it was the Autoguide port then you could damage the hand controller. If it no longer works I'd order another similar model (NexStar or NexStar+), re load the firmware with the latest gem/EQ version and carry on.
The camera port is used on the 4/5SE mounts and is there to trigger the shutter on a camera like a DSLR.
Edited by mclewis1, 09 November 2016 - 10:46 AM.
Posted 02 January 2020 - 12:47 AM
Looking for a replacement Power Board for the CG5 Advanced GT Mount. I know they are hard to come by these day, but does anyone have any suggestions on where to find this PCBA or alternate/upgrade equipment to run the mount?