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CGEM Drive noise

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#1 SanDiegoPaul

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Posted 08 April 2010 - 12:09 PM

My CGEM has gotten quieter over the past two months I've had it. It really is a wonderful unit, with incredible GOTO capeablility.

Yet even when using a 12V 3A regulated power supply, I hear the drives change pitch during slews as if there is resistance. Ya know, when you have a cable that's tugging and you hear the drive & it warns you to have a look at what's going on?

This mount has done this since day one. Is it a common thing? Using 4 stars and a careful alignment, I get terrific GOTO's and guiding. In fact I rarely even bother with Polar Alignment any more because this mount allows me to get 10-minute subframes with no prob at all.

But I am hearing these drives sound odd sometimes and I wonder if there's an issue. Again this is on 110V power, not battery power.

#2 RTLR 12

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Posted 08 April 2010 - 12:18 PM

Paul,

My CGEM does this too. Maybe with all the trouble you had now that things are going smoothly you're starting to look for things. Like race car drivers on the last lap of the race when they are in the lead they hear all sorts of things.

Or it could be something else!

Stan

#3 DaemonGPF

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Posted 08 April 2010 - 12:21 PM

My CG5 and LXD75 always did that since day one. Never had any problems though.

#4 SanDiegoPaul

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Posted 08 April 2010 - 12:25 PM

Thanks guys I feel better now. I come from the SCT only crowd and when the Meade SCT drive changes pitch, there's a problem.

Plus the first coupla times out I ~did~ have cables catch on the mount during slews and cause issues. So now that I watch out for cables & such I was still hearing the noise !!!

So I appreciate the feedback. Thanks

#5 nemo129

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Posted 08 April 2010 - 06:00 PM

Paul,
My CGEM does that as well. At first it really worried me, but it seems to perform well. My thought was that as the slew took the scope over the center of balance of the tripod/mount this would happen. Of course my idea may be all wet, but there has to be some reason for the change in pitch during the slew.

#6 waassaabee

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Posted 08 April 2010 - 08:00 PM

I've noticed my CGEM is very balance sensitive, and the motor noise lets me know. It's very accurate and tracks great so I don't worry about it. My CG5 was did the same sort of thing too. Put your headphones on and crank some tunes when slewing, and you'll never even notice... :rockon:

#7 DaemonGPF

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Posted 08 April 2010 - 08:53 PM

You can always crack the casing open and line it with sound suppression material or foam, and regrease the gears. It will cut the noise down significantly.

#8 David Pavlich

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Posted 08 April 2010 - 09:22 PM

I've noticed my CGEM is very balance sensitive, and the motor noise lets me know. It's very accurate and tracks great so I don't worry about it. My CG5 was did the same sort of thing too. Put your headphones on and crank some tunes when slewing, and you'll never even notice... :rockon:


Yep! The first thing I'd check if the motors are changing pitch would be the balance. I've had 2 CGEs and they would tell you under no uncertain terms, if the mount was out of balance.

David

#9 BlueGrass

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Posted 08 April 2010 - 10:55 PM

Paul,
Mine does the same and I'm pretty sure, as already suggested, that it is balance related. The mount does continue to track and slew fine. Since most of the time the mount is simply tracking, I don't worry too much since you need a slight imbalance to keep the worm constantly engaged. I also do notice a difference in amplitude if I'm using my SCT versus my AT106. I'm guessing that the vibration from the mount is somewhat louder using the SCT perhaps because the larger SCT tube acts like a resonator. As far as taking it apart and adding dampening material, I don't think there's much room to do this. It uses cast housings and they're pretty solid.

#10 WirelessDude

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Posted 12 April 2010 - 07:43 PM

Paul --

A good arrangement to consider regarding your cabling is bunching them all together and tying them close to the base of the dovetail's center-of-gravity, making sure you have slack for the DEC/focuser/rotator extremes...

You'll find that all your cable problems have disappeared! ;)

And, yes. Don't worry about the CGEM noise. I get them too!

Clear skies!

#11 SanDiegoPaul

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Posted 13 April 2010 - 12:41 PM

Thanks W-Dude!!






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