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Dec axis motor system faulty or newbie error?? #EXOS2


Paul Mogg
 

Last night, the DEC axis motor system on my new Exos 2 PMC-8 mount seemed to develop a problem and  stopped moving that axis at all. I tested it again this morning and it's the same. The clutches were all tight as I'd been advised, and It makes all the noises it normally makes when manually slewing using the compass rose controls, just doesn't physically move the DEC axis. I removed the cover to the belt drive on the DEC motor and all seems to be moving there correctly, and the belt is not broken or anything.

I'm aware that as a beginner I may be missing something basic here, but the clutches were tight on both axes, which is the only basic error I know of that could cause this.

Anyone got a clue before I call the fire brigade??
--
Location: southern Spain

Equipment:
Explore Scientific EOS-2 PMC-Eight mount
Skywatcher 200DPS Newtonian telescope
Telrad.
28mm 2" and 12mm 1.25" lenses.
2 and 5 x Barlows.
Macbook air 
Huawei Android T5 Tablet
Nikon D3200 DSLR
Software: ExploreStars Android & WIndows, Stellarium OSX & Android, AstroDSLR


Tony
 

Try opening the belt inspection door on the DEC side and see if the motor is moving, and if so, if the belt and big pulley are moving as well.  Perhaps the bolt that holds the DEC motor loosened up and the belt is slack, allowing the motor to spin without grabbing the belt.  Do you hear any clicking or other noises?  You said it sounds normal when slewing, so I assume you do hear the motor moving.

Good luck,
-Tony

On 10/16/2020 8:05 AM, Paul Mogg wrote:
Last night, the DEC axis motor system on my new Exos 2 PMC-8 mount seemed to develop a problem and  stopped moving that axis at all. I tested it again this morning and it's the same. The clutches were all tight as I'd been advised, and It makes all the noises it normally makes when manually slewing using the compass rose controls, just doesn't physically move the DEC axis. I removed the cover to the belt drive on the DEC motor and all seems to be moving there correctly, and the belt is not broken or anything.

I'm aware that as a beginner I may be missing something basic here, but the clutches were tight on both axes, which is the only basic error I know of that could cause this.

Anyone got a clue before I call the fire brigade??
--
Location: southern Spain

Equipment:
Explore Scientific EOS-2 PMC-Eight mount
Skywatcher 200DPS Newtonian telescope
Telrad.
28mm 2" and 12mm 1.25" lenses.
2 and 5 x Barlows.
Macbook air 
Huawei Android T5 Tablet
Nikon D3200 DSLR
Software: ExploreStars Android & WIndows, Stellarium OSX & Android, AstroDSLR


 

Paul,

If the DEC axis stays put when the clutch is on, then the clutch isn't slipping and neither is the mesh between the worm and ring gears.
If you open the belt cover and the belt is moving, but the axis isn't, then I would think that the most likely cause would be a loose setscrew on the large pulley.
Easy to check and service if you remove the DEC motor cover, not much to it.  Notes below :-)

https://espmc-eight.groups.io/g/MAIN/files/User%20Contributions/EXOS2PMC8_TuningNotes_v2.pdf
   
--
Mounts: ES PMC-8 EXOS2
Scopes: SV 102EDT, ZWO 60/280 Guide
Cameras:  Nikon D5300, Altair GPCAM2 290M
Software: ASCOM, CdC, AstroTortilla, BYN Pro, Sharpcap, PHD2
Computer:  Thinkpad x230, Win7Pro/64


Paul Mogg
 

Thank you very much for those notes Robert, and for your reply Tony. I will read your notes and see if I can fix it, whatever it is. My only concern is that if I attempt a repair or open the motor housing that I'll nulify my warranty on the mount. It's only 10 days or so old. 

Thanks again,

Paul
--
Location: southern Spain

Equipment:
Explore Scientific EOS-2 PMC-Eight mount
Skywatcher 200DPS Newtonian telescope
Telrad.
28mm 2" and 12mm 1.25" lenses.
2 and 5 x Barlows.
Macbook air 
Huawei Android T5 Tablet
Nikon D3200 DSLR
Software: ExploreStars Android & WIndows, Stellarium OSX & Android, AstroDSLR


Tony
 

I would certainly think you'd be fine opening the inspection door.  Its a simple clip in piece of plastic, no tools necessary.  You'll at least get a quick look inside.   Once you have a visual confirmation on what is slipping, hopefully support can advise you on the proper steps.  My guess is that it will mirror what Robert suggested, but you may want to wait to hear it straight from them.

Good luck,
-Tony



On 10/16/2020 12:35 PM, Paul Mogg wrote:
Thank you very much for those notes Robert, and for your reply Tony. I will read your notes and see if I can fix it, whatever it is. My only concern is that if I attempt a repair or open the motor housing that I'll nulify my warranty on the mount. It's only 10 days or so old. 

Thanks again,

Paul
--
Location: southern Spain

Equipment:
Explore Scientific EOS-2 PMC-Eight mount
Skywatcher 200DPS Newtonian telescope
Telrad.
28mm 2" and 12mm 1.25" lenses.
2 and 5 x Barlows.
Macbook air 
Huawei Android T5 Tablet
Nikon D3200 DSLR
Software: ExploreStars Android & WIndows, Stellarium OSX & Android, AstroDSLR


Paul Mogg
 

Yes I did that Tony, nothing to see, the belt is in place, the cogs turn. Unfortunately the Dec motor system started making a loud repetitive click last night as I suppose it is trying to track but can't. I tried taking my first pics of the Orion nebula last night but just got long star trails with a 30 sec exposure, ( lovely colors though, haha! ) the Dec motor isn't moving anything. 

I sent a message about this to Astroshop.eu the German company I bought it from, to try to figure out if I should attempt a repair myself, but haven't heard back yet. I really don't relish shipping this whole rig back to Germany if I don't have to, but don't want to touch it until I know how my Warranty will be affected, as it's brand new. Don't know if I need to also contact the US people at Explore Scientific too.

Thanks for your feedback.

Paul

--
Location: southern Spain

Equipment:
Explore Scientific EOS-2 PMC-Eight mount
Skywatcher 200DPS Newtonian telescope
Telrad.
28mm 2" and 12mm 1.25" lenses.
2 and 5 x Barlows.
Macbook air 
Huawei Android T5 Tablet
Nikon D3200 DSLR
Software: ExploreStars Android & WIndows, Stellarium OSX & Android, AstroDSLR


Tony
 

You're shooting with a 200mm newt, correct?  That's similar to my setup.  Are you sure your scope is well balanced with the camera and accessories attached?  It sounds like the motor may be straining.  The mount should be plenty strong enough to move a big newt, so long as its well balanced.  Sorry if  this seems like an obvious point, I just want to make sure.

How were you able to get to the Orion Nebula?  Did you use explore stars and slew to the target?  Were you platesolving in APT?  Or did you loosen the clutches and point the scope manually?

Also, if you were able to get the scope on target (M42) the DEC motor should be essentially still.  Only the RA motor would be turning to counteract the earth's rotation.  If you got star trails at 30 seconds, and assuming you had good polar alignment, it sounds like the RA axis is not turning.  Perhaps you have them confused?  Or perhaps both are straining? 

Please don't take any offense if my questions seem too rudimentary, I'm just trying to understand and confirm things. Hopefully you'll get some answers from Support soon.


On 10/17/2020 1:41 AM, Paul Mogg wrote:
Yes I did that Tony, nothing to see, the belt is in place, the cogs turn. Unfortunately the Dec motor system started making a loud repetitive click last night as I suppose it is trying to track but can't. I tried taking my first pics of the Orion nebula last night but just got long star trails with a 30 sec exposure, ( lovely colors though, haha! ) the Dec motor isn't moving anything. 

I sent a message about this to Astroshop.eu the German company I bought it from, to try to figure out if I should attempt a repair myself, but haven't heard back yet. I really don't relish shipping this whole rig back to Germany if I don't have to, but don't want to touch it until I know how my Warranty will be affected, as it's brand new. Don't know if I need to also contact the US people at Explore Scientific too.

Thanks for your feedback.

Paul

--
Location: southern Spain

Equipment:
Explore Scientific EOS-2 PMC-Eight mount
Skywatcher 200DPS Newtonian telescope
Telrad.
28mm 2" and 12mm 1.25" lenses.
2 and 5 x Barlows.
Macbook air 
Huawei Android T5 Tablet
Nikon D3200 DSLR
Software: ExploreStars Android & WIndows, Stellarium OSX & Android, AstroDSLR


James Ball
 

If you have just the bare mount, not scope or counterweights, does it seem to move correctly with only the high pitch noise of the motors and no clicking or grinding?
--
James Ball
Dawson Springs, Ky
Mounts: iEXOS-100
Scopes: Meade ETX90RA(deforked now) Sky Watcher 150MCT
Camera: ZWO ASI 120MC-S
Software: Explore Stars Android, ASCOM, Stellarium Scope, Stellarium, AS!3, SharpCap, RegiStax6.


Paul Mogg
 

Well I fixed it, took me while as I'm not used to doing any mechanical stuff, and finding the right hex keys etc. but it was exactly as Robert had predicted, both of the set screws holding the large pulley in place on the DEC motor assembly were completely loose on their spindle, so the motor was turning but it wasn't turning the head.

Many thanks again to Robert for his help and instruction sheet, and to Tony for his helpful suggestions.

Paul

--
Location: southern Spain

Equipment:
Explore Scientific EOS-2 PMC-Eight mount
Skywatcher 200DPS Newtonian telescope
Telrad.
28mm 2" and 12mm 1.25" lenses.
2 and 5 x Barlows.
Macbook air 
Huawei Android T5 Tablet
Nikon D3200 DSLR
Software: ExploreStars Android & WIndows, Stellarium OSX & Android, AstroDSLR


Paul Mogg
 

Tony, I got to the Orion Nebula using just the Telrad ( which is an amazing tool ) and loosened clutches, which is how I'd been it before getting the EXOS-2 PCM-8. I started about a month or so age using an old video tripod I had, with my Newtonian, but quickly realized that doesn't cut it for astronomy, it's down right dangerous frankly, the whole shebang nearly fell on me a few times. So anyway, the EXOS-2 is a big step up for me.
--
Location: southern Spain

Equipment:
Explore Scientific EOS-2 PMC-Eight mount
Skywatcher 200DPS Newtonian telescope
Telrad.
28mm 2" and 12mm 1.25" lenses.
2 and 5 x Barlows.
Macbook air 
Huawei Android T5 Tablet
Nikon D3200 DSLR
Software: ExploreStars Android & WIndows, Stellarium OSX & Android, AstroDSLR


 

Paul,

You're most welcome !   Glad it got sorted out.  :-)

- Bob

On Sat, Oct 17, 2020, at 09:22, Paul Mogg wrote:
Well I fixed it, took me while as I'm not used to doing any mechanical stuff, and finding the right hex keys etc. but it was exactly as Robert had predicted, both of the set screws holding the large pulley in place on the DEC motor assembly were completely loose on their spindle, so the motor was turning but it wasn't turning the head.

Many thanks again to Robert for his help and instruction sheet, and to Tony for his helpful suggestions.

Paul

--
Location: southern Spain

Equipment:
Explore Scientific EOS-2 PMC-Eight mount
Skywatcher 200DPS Newtonian telescope
Telrad.
28mm 2" and 12mm 1.25" lenses.
2 and 5 x Barlows.
Macbook air 
Huawei Android T5 Tablet
Nikon D3200 DSLR
Software: ExploreStars Android & WIndows, Stellarium OSX & Android, AstroDSLR


--
Mounts: ES PMC-8 EXOS2
Scopes: SV 102EDT, ZWO 60/280 Guide
Cameras:  Nikon D5300, Altair GPCAM2 290M
Software: ASCOM, CdC, AstroTortilla, BYN Pro, Sharpcap, PHD2
Computer:  Thinkpad x230, Win7Pro/64