replacing grease in EXOS2 #EXOS2


rickbram
 

So I think part of (or all of) my problem with losing correct slewing and guiding could be due to the factory grease, which may be too ungreasy. I would like to try to replace it with the moly-based grease that was suggested by y'all. I did manage to take off the motor and change the grease on the worm gears and get things back together. The mount seems to work OK inside. However, after being outside at night for a while, it really gets very hard to move the mount head around - even with the clutches completely off. Definitely not swinging freely. Dec seems much worse than RA. I guess the tuning notes PDF says not to try to fix this yourself at home, but should send back to EX to have it repaired or replaced. I would like to try this myself, though. Any advice? Is there a further instruction somewhere on how to change the grease further down inside the Dec axis? thank you


--
Rick, Minnesota USA
EXOS2-GT, Stellarmate/Astroberry, Askar FMA230, ASI294MCPro, ASI120mini guidescope, ASI120mini


 

Rick,
 
The tuning guide came about because I had a number of issues to work through on my mount, and when the dust finally settled, I realized that for most of them, the hard part was the detective work of figuring out what needed to be done.  The actual tips/adjustments/tweaks were pretty simple and well within scope for most people.  So I wrote that part up, and folks do seem to find it helpful.
 
I deliberately left out steps for remedying a sticky axis when balancing, because that's a whole 'nother thing.  In my case that involved a full teardown and rework, something that I doubted that most owners would need, or be up for.  
 
When balancing with clutches off, the ring gear is sliding against its central axle on a film of grease.  When the clutches are on, it is not.  Freedom of motion when tracking and freedom of motion when balancing are two different things.  
 
What I found during my teardown is that I had a tolerance problem between the ID of my ring gear and the OD of the axle it rides on.  When I finally wrestled it off, I found that it was so tight that I could not get it back on!  My solution was to buff out the ID of the ring gear with very fine 3M abrasive fabric.  Once it started to go back on, then switch to buffing out the scuffs from many trial fits (pic attached).  Eventually I had a decent fit, and could re-grease and reassemble.  
 
An interference fit was the source of my problem, not grease.  So that's why I recommended the mix I did, because the things in that tuning note are reasonable maintenance items, but a DIY repair of an axis that won't balance is a fairly big deal.   

Your axis movement when tracking is on the ball bearings and probably fine.  If you can balance your mount of while it is still warm from indoors, then I'd suggest you do that rather than dig into the axis or go through a service ticket with ES.  If you can't balance at all, then that's a different matter and I'd suggest a call to ES customer service.
 
Hope this helps...
 
- Bob
 
--
Mounts: ES PMC-8 EXOS2, Serial
Scopes: SW 130P-DS, SV 102EDT, ZWO 60/280 Guide
Cameras:  Nikon D5300, Altair GPCAM2 290M
Software: ASCOM 6.3, CdC, AstroTortilla, BYN Pro, Sharpcap, PHD2
Computer:  Thinkpad x230, Win7Pro/64


Micheal
 

Rick

   I just followed the direction and did remove the top to replace the grease on the Dec. It was still a little stiff last night at -12 below but motors handled it fine. One problem I'm having is serial connection. You have any trouble with this??.

After connection I was able to get around .38 to .45 arc sec total error on M42 and .28 to .34 arc sec error on M45. I slewed around showing my wife several star cluster after wards. Love the fact that I can be inside and run the mount from in side and can take 20 sec shoot without guiding and get very round Star . Great start for 2022 for US.

Micheal

IExos-100 and EXOS2GT both running PMC-Eight version 20A01.
iOptron Photron 150mm RC OTA
Svbony 503 80mm f7 w/ Orion 0.8 field flattener
Celestron 150mm C6n f7 w/motor focuser controlled w/ FCUSB Motor Controller
Svbony 50 mm guide scope on 80mm Scope
Svbony 60 mm guide Scope on 150 mm Scope
Cameras Canon T7, ZWO 224, ZWO 120mm, ZWO 120 MC 
DewBuster controller for 2 temp controlled dew strips, plus up to 4 additional dew strips, It also is Powering my Canon T7 camera, a 7 port USB Power hub, and fan for the 150mm Scope.

ASCOM 6.5 sp1 with Device Hub. Cartes Du Ciel for mount control, SharpCap for Polar alignment and planetary photos, Astro Photography Tool, platesolve2, PHD2 for guiding, and Stellarium for object framing only.

On 1/2/2022 4:25 AM, rickbram wrote:
So I think part of (or all of) my problem with losing correct slewing and guiding could be due to the factory grease, which may be too ungreasy. I would like to try to replace it with the moly-based grease that was suggested by y'all. I did manage to take off the motor and change the grease on the worm gears and get things back together. The mount seems to work OK inside. However, after being outside at night for a while, it really gets very hard to move the mount head around - even with the clutches completely off. Definitely not swinging freely. Dec seems much worse than RA. I guess the tuning notes PDF says not to try to fix this yourself at home, but should send back to EX to have it repaired or replaced. I would like to try this myself, though. Any advice? Is there a further instruction somewhere on how to change the grease further down inside the Dec axis? thank you


--
Rick, Minnesota USA
EXOS2-GT, Stellarmate/Astroberry, Askar FMA230, ASI294MCPro, ASI120mini guidescope, ASI120mini


Eduardo Simone
 

Michael,  

what length serial cable are u running. Are u running a 50’ usb to serial cable. If so, is it a name brand, some of the cheaper cables at longer lengths tend to drop out. Also are u using a Prolific or FTDI chipset. These guys on here all go with the FTDi. I use a prolific cable but only a 6’ footer. 


Ed
--
ES 127mm Achromat doublet refractor
ExploreScientific Exos II with PMC-8
Meade 152mm LX80 SCT
ZWO ASI533MC-Pro
ZWO ASI120MC


Micheal
 

Ed

Thanks for the feed back.

   Yes serial cable from USB hub to pmc-8 is a 6'-0 with the FTDI Chipset. Then I have a 6'0 USB 3 cable from hub to my 50' USB 3 cable that is also powered to get pass the 9 1/2' USB cable length. Every thing seem to work fine after its connected.  Just getting consistent connection is my problem. After toughing all the cable post it fired up last night.

Thinking of switching out the hub but my focuser likes the 7 port hub as it supplies  5 amp instead of the typical 2.4. That and will try different Wi-Fi channel also.

Micheal

IExos-100 and EXOS2GT both running PMC-Eight version 20A01.
iOptron Photron 150mm RC OTA
Svbony 503 80mm f7 w/ Orion 0.8 field flattener
Celestron 150mm C6n f7 w/motor focuser controlled w/ FCUSB Motor Controller
Svbony 50 mm guide scope on 80mm Scope
Svbony 60 mm guide Scope on 150 mm Scope
Cameras Canon T7, ZWO 224, ZWO 120mm, ZWO 120 MC 
DewBuster controller for 2 temp controlled dew strips, plus up to 4 additional dew strips, It also is Powering my Canon T7 camera, a 7 port USB Power hub, and fan for the 150mm Scope.

ASCOM 6.5 sp1 with Device Hub. Cartes Du Ciel for mount control, SharpCap for Polar alignment and planetary photos, Astro Photography Tool, platesolve2, PHD2 for guiding, and Stellarium for object framing only.

On 1/2/2022 7:24 PM, Eduardo Simone wrote:

Michael,  

what length serial cable are u running. Are u running a 50’ usb to serial cable. If so, is it a name brand, some of the cheaper cables at longer lengths tend to drop out. Also are u using a Prolific or FTDI chipset. These guys on here all go with the FTDi. I use a prolific cable but only a 6’ footer. 


Ed
--
ES 127mm Achromat doublet refractor
ExploreScientific Exos II with PMC-8
Meade 152mm LX80 SCT
ZWO ASI533MC-Pro
ZWO ASI120MC