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#1 spmv

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Posted 12 July 2009 - 01:00 PM

Hopefully someone can help me hear. My fear is having to return this mount after receiving it on Thursday.

So hears what it's doing. During alignment while slewing to the first star the RA axis moves a degree or so then stops. I've tried multiple stars. The Dec seems fine. The RA axis moves freely while unlocked, no binding. It also seemed fine skipping the alignment. But when I tried moving in dec at the same time the RA motors refused to kick in. I have tried 3 batteries same result.

New scope will be hear tomorrow. Go figure. :grin:

#2 neptun2

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Posted 12 July 2009 - 01:49 PM

What is the firmware version on the hand controller?

#3 John J

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Posted 12 July 2009 - 02:48 PM

You must also make sure the scope is balanced very well. The stepper motors in the Atlas mounts require good scope balance due to their low torque. My atlas stalled several times until I balanced right.

Does it make a grinding noise when it stops? Also recheck ALL the settings on the hand control. Make sure you have your date and time set properly. Lat and Long must be correct. Check the connection at the hand control as some times that can make poor contact. Unplug it and plug it back in a couple of times.

JJ

#4 spmv

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Posted 12 July 2009 - 03:03 PM

It's version 3.23.

John, I did everything without a scope. It makes a grinding noise at the beginning and end of a slew. Once it's up to speed it's fairly quiet. I've checked all the settings and also went back to the factory settings then back again. I've checked all the pins on every connection. They all look good.

Thanks for your input guys. I really appreciate it. I'll keep looking for a solution.

#5 John J

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Posted 12 July 2009 - 03:21 PM

The grinding noise is the stepper motor stalling. I will not damage any thing but you could have a couple of things wrong.

The mesh between the worm and RA gear is to tight or the ra motor gear mesh to the worm is to tight.

On the RA axis on the back side of it are four hex head bolts. Try loosening all of them to relax the tension on the RA worm and RA gear. I don't think this void your warranty as long as you don't ream the bolts. I had to adjust my mounts mesh. At the top and bottom of the RA axis are two tiny set screws that help to adjust the gear mesh.

JJ

#6 spmv

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Posted 12 July 2009 - 04:49 PM

John, I'll try what you suggested. It's difficult without actually opening up the mount. I'll let you know if I make any progress. Thanks again.

#7 spmv

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Posted 12 July 2009 - 04:51 PM

I should have gone with my gut and bought a G11 or even a DM 6.

#8 John J

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Posted 12 July 2009 - 05:17 PM

Is the mount new or used? It may have taken a good shot during shipping that knocked the gear mesh out. All screws are metric also. To adjust the motor to worm mesh you will have to open the electronics board up. Try the relaxing of the four bolts first. That is usually the main problem.
JJ

#9 jrbarnett

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Posted 12 July 2009 - 08:58 PM

Mine always makes the grinding noise at the beginning and end of slews. Mine works perfectly and has done so for several years. I'm running v3.21 still. I've used two others that did exactly the same (slewing noises). I think the grinding at the start and end of slews is a red herring. If you get grinding noises mid-slew, however, that's a stall. Mine does that when the battery is about dead.

When you were playing with the mount without an OTA attached, did you have a counterweight on the bar? If so, perhaps that's the problem. Remove the weight(s) and try your slews. Can you manually slew in RA and Dec (i.e., using the hand controller but not the GOTO feature)?

I also don't think the G-11 is necessarily a cure all. We have a club mate that hasn't been able to get his G-11 working properly for two months. The first problem was defective motors, replaced by Losmandy. The second is inaccurate slews. Even folks who have had Gemini mounts can't get this G-11 to work properly.

Good luck,

Jim

#10 John J

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Posted 12 July 2009 - 09:31 PM

My mount makes no grinding sounds at all. The motors are supposed to start out slow and ramp to speed on a slew. Most of my club members are amazed at how silent it is when slewing. Course they have the CG 5's and LXD 75's.
JJ

#11 jrbarnett

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Posted 12 July 2009 - 10:02 PM

Yup. Some are quieter than others. I've also heard a couple that had barely audible start-up and slow-down pitch changes. My point was that the presence or absence of grind at the beginning and end of slews does not necessarily have any realtionship to his problem given that many Atlas mounts make those noises yet function flawlessly with accurate tracking and GOTOs. Even the grinders like mine are much quieter than other mounts. At track and mid-slew it's nearly silent.

Regards,

Jim

#12 Charlie Hein

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Posted 12 July 2009 - 11:02 PM

There were a couple of revisions to the design of the transfer gear on the motor side. The newest ones are held in place by a post that you press through the transfer gear and tighten down to the frame of the motor with a couple of allen screws. It's this arrangement that is causing the transfer gear to rattle (not really grinding at all) as it ramps up and down in speed. It isn't anything to be concerned with at all, as you really can't do anything about it besides machining the transfer gear to take a bearing and tapping the motor casing to take a threaded screw or bolt to hold it in place as opposed to that post they use now.

Question for spmv: Can you set the slew rate for say 7 or 8 and see the mount move when you manually select east or west (right/left) direction buttons?

#13 John J

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Posted 13 July 2009 - 02:12 AM

My mount is one of the early black SkyWatcher EQ6 ones. From what I remember the transfer gear has 2 set screws that tighten down on the motor shaft. The motor has a bracket that has 2 slotted screw holes that you can use to adjust the transfer gear mesh to the worm gear.

I wonder why they would change the design as it seems to work very well and very quiet. Mine you can barely hear it even at full slew rate.

JJ

#14 Charlie Hein

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Posted 13 July 2009 - 05:56 AM

I wonder why they would change the design as it seems to work very well and very quiet.


It is almost certainly less costly to produce this way and does not seem to materially affect the tracking.

#15 spmv

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Posted 13 July 2009 - 05:57 AM

Jim, no counterweight. It does the same thing manually. I've adjusted the slew rate from 4-9. Now it will "sometimes" work. I was able to move in RA maybe 30 degrees then back again, but then I tried moving in both axes at the same time and it stopped dead. When doing the alignment though it doesn't move at all in RA.

I'll mess around a bit more. Thanks everyone!

#16 hickeydp

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Posted 13 July 2009 - 07:32 AM

I don't know this mount but your problem sounds very like one I had with a LXD75. For me it was the gears on the motor and the worm were meshed too tightly together. It only took the smallest of movement (less then a mm) to loosen them up. May just need to back it off a fraction.

#17 neptun2

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Posted 13 July 2009 - 07:44 AM

Look at this topic that i post: link
I hope that this is not your problem but if you do not open the mount you can't be sure what is happening there.

#18 Charlie Hein

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Posted 13 July 2009 - 09:57 AM

Jim, no counterweight. It does the same thing manually. I've adjusted the slew rate from 4-9. Now it will "sometimes" work. I was able to move in RA maybe 30 degrees then back again, but then I tried moving in both axes at the same time and it stopped dead. When doing the alignment though it doesn't move at all in RA.

I'll mess around a bit more. Thanks everyone!



Sounds like you may have a wonky hand controller. If you have a buddy with an Atlas you might want to check the HC and cable for truouble by swapping temporarily. At this point I'd be considering contacting your dealer.

#19 Brodie

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Posted 13 July 2009 - 11:16 AM

if you want to check if its a SYNSCAN (hand controller) problem you could always install EQMOD (free) and connect the mount directly to you pc through the hand controller. (make sure it has the latest firmware version and set to "PC Direct" in the utilites. If the mount is still acting up, then its probably not the hand controller.

#20 spmv

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Posted 13 July 2009 - 12:10 PM

Wow! Things just got worse. No power. Nothing. All of my batteries and connections are good. Contacted the dealer and they agreed. The mount is defective and its going back. I will not get another Atlas. Probably a non Gemini G11.

Thanks for all your help everyone.






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