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CGEM RA motor making loud jolty noises -emergency

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#1 corpusse

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Posted 06 September 2012 - 08:36 PM

Just as I'm about to take my CGEM off the pier and take it to the darkest site I've ever been to I'm having problems. The RA motor is jolting at higher speeds (maybe slower too). If a sound clip would help I can make one. I don't currently have a finder on and have to realign but I wanted to post this first. It seems to be pointing in the general right area and I was able to take a 30 second unguided sub with a 66mm refractor and it tracked the stars just fine. I am however very concerned.

Any ideas or suggestions? I have to have the mount packed up by tomorrow morning.

#2 Stew57

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Posted 06 September 2012 - 08:49 PM

Are you sure you were balanced. I have one weight that wants to slide no matter how tight I seem to get it. i always stack it on top.

#3 corpusse

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Posted 06 September 2012 - 09:03 PM

Seems to be. It seems okay after a few seconds. Here is a video with the sound

http://www.youtube.c...be_gdata_player

#4 RTLR 12

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Posted 06 September 2012 - 09:10 PM

Remove the sprur gear inspection screw and look at the gear mesh for the RA axis.

Stan

#5 corpusse

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Posted 06 September 2012 - 09:22 PM

Remove the sprur gear inspection screw and look at the gear mesh for the RA axis.

Stan


Hi Stan can you explain further?

Thanks

#6 RTLR 12

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Posted 06 September 2012 - 09:28 PM

It sounds as if the gear mesh is to wide for the spur gear on the motor to the spur gear on the worm gear shaft. On the side of the main body of the mount, just below the worn gear shaft plastic end covers, there are some chrome slot head screws. Remove these screws and you can see the spur gears.

Stan

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#7 corpusse

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Posted 06 September 2012 - 09:55 PM

It sounds as if the gear mesh is to wide for the spur gear on the motor to the spur gear on the worm gear shaft. On the side of the main body of the mount, just below the worn gear shaft plastic end covers, there are some chrome slot head screws. Remove these screws and you can see the spur gears.

Stan


I think you are correct. It appears the motor is getting stuck then jumping. I am uploading poor quality videos.

I guess my next question is how do I fix this? I see a LOT of grease on the RA gears not so much on the DEC which is running smooth.

I have 4hrs to pack this up or bust.

#8 corpusse

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Posted 06 September 2012 - 09:59 PM

This video is showing the slower speeds 2,3,4

http://www.youtube.c...h?v=RpTe7xsheDk

on 9 it only stalls at first and then seems fine.

#9 orlyandico

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Posted 06 September 2012 - 10:08 PM

Post deleted by orlyandico

#10 RTLR 12

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Posted 06 September 2012 - 10:16 PM

You need to remove the 4 screws holding the control panel on. Then you can adjust the gear mesh by loosening the motor retaining screws and moving the motor. Only slightly loosen the screws and use a large screw driver to position the motor for proper gear mesh.

Stan

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#11 orlyandico

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Posted 06 September 2012 - 10:19 PM

go to this page - http://www.astro-bab...m alignment.htm

go to the section "EQ6/Atlas Motor Gear Removal and Adjustment" (it's almost at the end). I've put the pics here for reference -

Posted Image

Posted Image

Posted Image

the procedure is exactly the same - remove the faceplate, then loosen the offending motor hold-down bolts. The CGEM uses servos so the motors look different (long and cylindrical).

Do not follow astro baby's instructions entirely and remove the motor!!! you just want to adjust the motor

Loosen the motor, then nudge it closer to the worm. In the case of the RA you want to push the motor to the right (toward the polar scope eyepiece direction).

Only use finger pressure (do not over-tighten, just eyeball the spur gear meshing through the peep hole). When the meshing looks good tighten the motor hold-down bolts. Put the cover back on, run the mount and listen for weird noises.

#12 corpusse

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Posted 06 September 2012 - 10:21 PM

Okay this certainly seems like something I can do. I'm going to pack everything up first. This is a 6 night trip so hopefully everything goes smooth.

Saying thanks doesn't seem like enough. You may have saved my trip :)

#13 RTLR 12

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Posted 06 September 2012 - 10:36 PM

Enjoy your trip my friend.

Stan

#14 orlyandico

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Posted 06 September 2012 - 10:38 PM

Don't forget the tools.. you will need a metric hex (allen) key to loosen the motor. And it will have to be fairly long.

#15 corpusse

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Posted 06 September 2012 - 11:53 PM

Okay so I have everything ready and just a few hours to go. I have the right allen key in case I need it but just to be clear, do I only have to adjust the 2 screws or the hexes as well? After losening the 2 screws the motor does not appear to move at all.

#16 RTLR 12

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Posted 07 September 2012 - 01:53 AM

You need to loosen the 2 Allen head screws shown in my pic. These screws hold the motor. You do not want to get the gears adjusted too tightly. Just close enough as to not skip. The tighter the gears are adjusted the louder the motors will be.

Stan

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#17 EFT

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Posted 07 September 2012 - 10:35 AM

I hope that you brought a full set of allen wrenches with you because it is likely that you need to adjust the worm spacing more than the spur spacing. If gears are binding, like it sounds, it is the worm spacing that is the problem. If things are simply noisy, then the spur spacing (and wobble) causes that.

#18 corpusse

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Posted 07 September 2012 - 12:53 PM

I hope that you brought a full set of allen wrenches with you because it is likely that you need to adjust the worm spacing more than the spur spacing. If gears are binding, like it sounds, it is the worm spacing that is the problem. If things are simply noisy, then the spur spacing (and wobble) causes that.


Just brought the one lol. I did just order a hypertune kit from you though. Since this is the one and perhaps only time I will have the mount off the pier there will never be a better time. Hopefully it will arrive shortly after I get back.

Tomorrow I will post an update and hopefully will have good news.

#19 corpusse

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Posted 10 September 2012 - 11:37 AM

Still haven't got it right but I'm assuming I just need more trial and error. I will keep playing as I have just a few more nights to get one decent photo.

I think it's actually easier in the white zone where you can count the number of stars and nothing is around Polaris. I thought it s cloudy the first night but the was the milkyway! I found the double cluster in my finderscope m42 is the only object I can find at home without goto.

Its just too bad about this motor problem. It did give me the incentive to buy the hypertune kit at least and I may yet get the photo I want.

#20 EFT

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Posted 10 September 2012 - 11:41 AM

It's always funny when you go from light poluted skys where all you can easily see are the brightest stars to someplace that's so dark you can't pick out your alignment stars. I know the feeling.

#21 corpusse

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Posted 10 September 2012 - 12:12 PM

So I had the mount open and just kept doing slight turns and it doesn't seem to have any effect as far as the noise. The motor has been moved around but no change. This has finished me for go to but I think I can still do wide field and if by chance I find anymore dso's tracking is probably okay as at speeds 1-2 it seems alright and also at 9 after a second of stalling / weird noise.

#22 orlyandico

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Posted 10 September 2012 - 12:26 PM

if moving the motor around doesn't change the noise you are probably binding the worm on a high spot on the ring gear.

#23 EFT

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Posted 10 September 2012 - 12:37 PM

The problem is not the spur gear spacing but the worm spacing. The spur gears produce noise but they don't bind. Binding comes from the worm and ring gear. Adjusting the worm spacing requires a 5mm and a 2mm allen wrench. If you have those available, drop me a line directly at edwardthomas@deepspaceproducts.com and I will send you some instructions on the adjustment. Otherwise, it is definitely something that you will work on when you HyperTune the mount.

#24 corpusse

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Posted 11 September 2012 - 10:48 AM

So I seem to have made things much worse. The mount is no longer moving in RA I think I've knocked the worm. Perfectly clear today too.

I'm going to keep trying but worst case can I flip the mount and use the dec tracking as RA and at least get some milkyway shots?

This truly is a disaster. I've had the mount since 2009 and other then the hand controller going and a few power issues at the start I've never had problems..

#25 orlyandico

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Posted 11 September 2012 - 11:14 AM

if the mount is no longer moving in RA maybe the spur gear no longer engages? so the motor turns but the worm does not.

or do you mean the worm is so tight against the worm wheel that the motor stalls?

when you lock the RA clutch, can you move the mount? (if you can then the worm is probably so far away from the worm wheel that it no longer engages)






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