Mach1 play in RA Axis - did not adjust out with Gear Mesh adjustment


John Davis
 

I have a new-to-me Mach1 that I received last week via UPS from its original owner.  The mount was securely shipped in a pelican case with a custom foam cutout that securely held it in place.  

I have now begun to assemble the mount on its new tripod, and after putting the mount on the tripod, I noticed that there was some play in both the Dec and RA axies with the clutches finger tightened.  I read the section of the Manual about the Gear Mesh adjustments.  This mount was sold new in June 2016, so it has the auto-adjusting motor gearbox.  I followed the instructions in this section of the manual to perform those adjustments.  That adjustment took all the play out of the Dec axis - it is rock solid now.  However, the RA axis still has seemingly the same amount of play in it as it did before the adjustment.  I repeated the process on the RA axis another time or two to make sure that I did it correctly.

I'd like some input from you all who are long-term owners about what the problem might be (if it is a problem) and what the solution might be.  I've contacted AP but have not heard back from them yet.

I've attached a short video illustrating what I'm seeing.
Thanks!


Roland Christen
 

There is a lever on the side of the gearbox. It is under a cover that snaps off if you pull on it. With counterweight down and no scope on the mount, turn the lever fully counterclockwise (about 180 degrees from the locked position). Doing that, you will pull the gearbox completely out of mesh, so that the worm gear teeth and the worm wheel teeth are no longer in contact with each other. Take a look at this position of the gearbox and familiarize yourself with the action so that you understand fully how the worm gear and worm wheel are meshed together, and how the gear and wheel actually work.

Once you understand that, turn the lever 1/2 way clockwise so that it points up (about 90 degrees from the unlocked position). Notice how the gearbox moves the worm gear into the teeth of the worm wheel. At this point the spring is pushing the entire gearbox assembly in a clockwise direction and the two gears should be fully mated. You can manually pull the gearbox away from mesh with your hand and you will feel the spring action wanting to push it back into mesh.

Once you fully understand that action, turn the lever gently clockwise until you can feel some resistance, or until it snaps into place pointing toward the worm gears. In that position you should be able to pull the gearbox back from mesh only very slightly because now there is a backstop preventing the gears from coming out of mesh. You can adjust the backstop position by loosening the two screws on either side of the lever and gently pushing the plate downward with finger pressure and tightening the two screws while maintaining that pressure.  This should cause the worm and worm wheel to be fully engaged and fully meshed.

Now, if the axis still moves when you put slight pressure on the counterweight shaft, then there are two possibilities. The worm is held in place by an end nut. If this nut comes loose (due to shipping vibration) then the worm can move back and forth and make it look like the gears are not in mesh. You can out your finger on the end of the worm gear and rock the axis via the cwt shaft - you may be able to feel the worm move. If it does, then the end play nut is loose and needs to be tightened. If it does not move and is tight then there are two other possibilities.

Your counterweight shaft might be loose in it's threaded end adapter. Tighten it and try again.

The second possibility is that the main bearing retainer nut has vibrated loose during shipping. That can be easily tightened. You will need to remove the counterweight shaft and the cwt adapter on the end of the RA axis. You can then look inside the axis and see the main bearing retainer nut. You can hand tighten it with a simple spanner wrench.

Try these suggestions and see if any of them work. The mount is quite basic, and once you play around with it a bit you will begin to understand how it is put together. Nothing fancy about this mount and nothing you can really mess up if you are in the least mechanical.

Rolando



-----Original Message-----
From: John Davis <johncdavis200@...>
To: main@ap-gto.groups.io
Sent: Tue, Sep 29, 2020 6:34 pm
Subject: [ap-gto] Mach1 play in RA Axis - did not adjust out with Gear Mesh adjustment

I have a new-to-me Mach1 that I received last week via UPS from its original owner.  The mount was securely shipped in a pelican case with a custom foam cutout that securely held it in place.  

I have now begun to assemble the mount on its new tripod, and after putting the mount on the tripod, I noticed that there was some play in both the Dec and RA axies with the clutches finger tightened.  I read the section of the Manual about the Gear Mesh adjustments.  This mount was sold new in June 2016, so it has the auto-adjusting motor gearbox.  I followed the instructions in this section of the manual to perform those adjustments.  That adjustment took all the play out of the Dec axis - it is rock solid now.  However, the RA axis still has seemingly the same amount of play in it as it did before the adjustment.  I repeated the process on the RA axis another time or two to make sure that I did it correctly.

I'd like some input from you all who are long-term owners about what the problem might be (if it is a problem) and what the solution might be.  I've contacted AP but have not heard back from them yet.

I've attached a short video illustrating what I'm seeing.
Thanks!


John Davis
 

Rolando - 
   I've read through your post about 4 times now - looking at the mount.  Is the adjustment that you are describing here the same as is outlined in https://www.astro-physics.info/tech_support/mounts/mach1gto/mach1gto-auto-adjusting-gearbox.pdf --- or is this a different/additional adjustment?  I'm a bit confused.  If you are describing what is in the pdf at that link - then I have attempted that adjustment several times, and it has made no difference in the amount of play. 

I have checked the counterweight shaft - it is tightly attached - that is not the source of the motion.  Tomorrow I will remove the declination assembly and check the main bearing retainer nut.

Please advise if I am mis-understanding the worm adjustment that you are describing. 
Thanks and sorry for being so dense understanding your post.
John


Roland Christen
 


've read through your post about 4 times now - looking at the mount.  Is the adjustment that you are describing here the same as is outlined in https://www.astro-physics.info/tech_support/mounts/mach1gto/mach1gto-auto-adjusting-gearbox.pdf --- or is this a different/additional adjustment?  I'm a bit confused. 
The adjustment that is in the PDF is correct. However, it is fundamental and lacks some context that would let you understand exactly what is happening. I attempted to give you some instructions so that you can get a full appreciation and better understand exactly what this lever does when you lock and unlock the gearbox.

What you are actually doing when you rotate the lever counterclockwise is the following: the first 90 degrees of rotation backs off the backstop, but does not take the gears out of mesh. The next 90 degrees counterclockwise pulls the gears out of mesh. Turning it clockwise reverses the action. Until you understand that you will have no clue as to what this lever actually does and why the adjustment is there for you. We have had a number of customers in the past actually adjust the backstop backwards which made the gears go out of mesh rather than go into mesh. So, I just wanted you to have the full knowledge of how the system works and not treat it like a black box that you need to be afraid of.

Rolando


-----Original Message-----
From: John Davis <johncdavis200@...>
To: main@ap-gto.groups.io
Sent: Tue, Sep 29, 2020 10:32 pm
Subject: Re: [ap-gto] Mach1 play in RA Axis - did not adjust out with Gear Mesh adjustment

Rolando - 
   I've read through your post about 4 times now - looking at the mount.  Is the adjustment that you are describing here the same as is outlined in https://www.astro-physics.info/tech_support/mounts/mach1gto/mach1gto-auto-adjusting-gearbox.pdf --- or is this a different/additional adjustment?  I'm a bit confused.  If you are describing what is in the pdf at that link - then I have attempted that adjustment several times, and it has made no difference in the amount of play. 

I have checked the counterweight shaft - it is tightly attached - that is not the source of the motion.  Tomorrow I will remove the declination assembly and check the main bearing retainer nut.

Please advise if I am mis-understanding the worm adjustment that you are describing. 
Thanks and sorry for being so dense understanding your post.
John


John Davis
 

Sorry - 2 more questions Rolando:

1). How do I get to the Worm end nut?  I see a round cap on the gear box - but it does not easily move - so I was not comfortable trying to force it  to move - is that the access point to get to the Worm end nut?  If so - how is it removed. If not please tell me where it is accessed

2). you described removing the "cwt adapter on the end of the RA axis" - I'm not sure what this referrs to.  I removed the Dec axis assembly which gave me access to the inside of the RA clutch assembly, but I did not see anything that looked like the "main bearing retainer nut" - could you clarify your description of how to access that retainer nut?

Thanks - sorry to be so dense about this - I'm reading the manual looking for these descriptions of parts - and things do not match up, and I'm being extra cautious at this early point in my ownership of the Mach1.

John


Roland Christen
 

The black nut covering the worm end simply unscrews. Check that first before you check the main bearings.

Rolando

-----Original Message-----
From: John Davis <johncdavis200@...>
To: main@ap-gto.groups.io
Sent: Wed, Sep 30, 2020 9:21 pm
Subject: Re: [ap-gto] Mach1 play in RA Axis - did not adjust out with Gear Mesh adjustment

Sorry - 2 more questions Rolando:

1). How do I get to the Worm end nut?  I see a round cap on the gear box - but it does not easily move - so I was not comfortable trying to force it  to move - is that the access point to get to the Worm end nut?  If so - how is it removed. If not please tell me where it is accessed

2). you described removing the "cwt adapter on the end of the RA axis" - I'm not sure what this referrs to.  I removed the Dec axis assembly which gave me access to the inside of the RA clutch assembly, but I did not see anything that looked like the "main bearing retainer nut" - could you clarify your description of how to access that retainer nut?

Thanks - sorry to be so dense about this - I'm reading the manual looking for these descriptions of parts - and things do not match up, and I'm being extra cautious at this early point in my ownership of the Mach1.

John


John Davis
 

Will do. Thanks!


John Davis
 

Ok. Removed the cover for the worm.  I did not feel any movement of the Worm when I moved the clutch assembly.  So that does not appear to be the problem.
On to the main bearing retainer nut... 


Roland Christen
 

Before you do that, go back to my first post and do what I suggested.
Then, with the lever half way up (90 degrees from fully locked), gently push on the counterweight shaft with 1 finger back and forth and see if the axis rocks. Very gentle push back and forth, 1 finger.

Roland Christen
Astro-Physics inc.
aka Rolando



-----Original Message-----
From: John Davis <johncdavis200@...>
To: main@ap-gto.groups.io
Sent: Thu, Oct 1, 2020 9:26 am
Subject: Re: [ap-gto] Mach1 play in RA Axis - did not adjust out with Gear Mesh adjustment

Ok. Removed the cover for the worm.  I did not feel any movement of the Worm when I moved the clutch assembly.  So that does not appear to be the problem.
On to the main bearing retainer nut... 


John Davis
 

Hi Roland,
  I went back and meticulously re-read your first post, and attempted to the best of my abilities to re-do everything that you suggested- just as you suggested, including the steps to familiarize myself with the behavior of the meshing mechanism.  Everything behaved just as you described.

  I re-performed the meshing procedure following your instructions and those in the documentation for the mount.  That procedure still did not ellimnate the play in the RA axis, as it DID when I performed the same procedure on the Dec axis.  Because that worked, I conclude that I followed the procedure correctly.

  I then added your last step to move the lever to the 90 degree position from fully locked, and gently with one finger pushed back and forth on the end of the counterweight shaft - and it still moved as it does when the lever is pointing to the fully engaged and locked position.

  After all this I re-checked the worm nut - with the cap removed, I cannot feel any movement of the worm shaft when moving the counterweight shaft with my finger.

John


Roland Christen
 

The Mach1 is an extremely simple mount. The RA axis has two bearings, one at the upper end of the RA body and one near the middle of the body. There is a sliding window on top of the RA body that can be slid up and out of the way (this is the window where people run their cables thru the mount).

Sliding this window out of the way allows you to actually look inside the RA body, which is hollow, and you will see the shaft bearing retaining nut that preloads the bearings. It's a black anodized ring with two holes on the ends that allow a spanner wrench for tightening. Further up you can see the shaft which is clear anodized (silver). The bearing itself is underneath the black ring.

If it's loose, then the axis shaft can move a bit inside the bearing. You can look right in that opening and see the end of the RA shaft bearing retaining ring and check to see if it moves as you push on the counterweight shaft. You can even put your finger on the retaining nut and feel if there is any movement if you can't see it by eye.

There is nothing whatsoever left that can allow the RA axis to move when you push back and forth on the counterweight shaft.

Roland Christen
Astro-Physics Inc.



-----Original Message-----
From: John Davis <johncdavis200@...>
To: main@ap-gto.groups.io
Sent: Thu, Oct 1, 2020 4:59 pm
Subject: Re: [ap-gto] Mach1 play in RA Axis - did not adjust out with Gear Mesh adjustment

Hi Roland,
  I went back and meticulously re-read your first post, and attempted to the best of my abilities to re-do everything that you suggested- just as you suggested, including the steps to familiarize myself with the behavior of the meshing mechanism.  Everything behaved just as you described.

  I re-performed the meshing procedure following your instructions and those in the documentation for the mount.  That procedure still did not ellimnate the play in the RA axis, as it DID when I performed the same procedure on the Dec axis.  Because that worked, I conclude that I followed the procedure correctly.

  I then added your last step to move the lever to the 90 degree position from fully locked, and gently with one finger pushed back and forth on the end of the counterweight shaft - and it still moved as it does when the lever is pointing to the fully engaged and locked position.

  After all this I re-checked the worm nut - with the cap removed, I cannot feel any movement of the worm shaft when moving the counterweight shaft with my finger.

John


John Davis
 

Thanks for that detailed description - I found the parts as described, and when I moved the counterweight shaft, I could not see or feel any movement of the silver shaft.  The counterweight arm does still move just as before.

So my ultimate question: is it a problem that the cw shaft moves the amount shown in the video clip (attached to the first post) when the worm is engaged - with or without the clutch engaged?  I was just trying to determine that first - and then if so - how to adjust it out.  Sounds like I've reached the end of the line as far as finding the source of the play.

I'm planning to continue setting the mount up - and getting ready to take it out to the field - then I suppose I'll see if this is an issue or not when imaging.  I was just hoping to remove any source of problems in the field before I go out.

thanks,
John


Mike Dodd
 

May I butt in to ask a basic question?

On 10/1/2020 11:13 PM, John Davis wrote:
Thanks for that detailed description - I found the parts as described,
and when I moved the counterweight shaft, I could not see or feel any
movement of the silver shaft. The counterweight arm does still move
just as before.
QUESTION: Is the CW shaft screwed-in tightly?

Put your fingers at the connection between the CW shaft and the housing. Can you feel movement? If so, the answer to this question is "NO."

I'm not familiar with the Mach1, but if something moves at point X (the CW shaft), but not at point Y (the worm wheel or worm itself), then something must be loose between points X and Y.

But what do I know? Just a thought....

Mike


John Davis
 

Hi Mike - you aren't butting in - any suggestion is appreciated.

Unfortunatley the CW shaft is rock solid - not the source of the play.  I checked that multiple times, and the play is sitll there even with the Dec axis assembly removed.  I wish the solution was that simple.

Thanks for the suggestion!
John


Cheng-Yang Tan
 

Hi John,
   I haven't read the entire thread and Rolando is the expert.

   Here's what I did to remove the RA play with instructions from Rolando and Howard
main@ap-gto.groups.io | Advice needed: I can rock RA in Mach1GTO (very small), should I adjust?



Here's the photos of the nut that I had to tighten by about a 1/4 turn. And then adjust the backstop. After that, my RA is rock solid. And dare I say, I measured my PE after the adjustment and it has also improved.


Inline image
Inline image

cytan


On Friday, October 2, 2020, 07:46:19 AM CDT, John Davis <johncdavis200@...> wrote:


Hi Mike - you aren't butting in - any suggestion is appreciated.

Unfortunatley the CW shaft is rock solid - not the source of the play.  I checked that multiple times, and the play is sitll there even with the Dec axis assembly removed.  I wish the solution was that simple.

Thanks for the suggestion!
John


John Davis
 

Thanks so much for the information!  Just knowing that others have seen the issue and were able to fix it helps a lot.


Roland Christen
 

If you cannot find the source of the play, perhaps you might send the RA axis in for examination. Just contact the office and ask for a return authorization number.

Roland Christen
Astro-Physics Inc.



-----Original Message-----
From: John Davis <johncdavis200@...>
To: main@ap-gto.groups.io
Sent: Thu, Oct 1, 2020 10:13 pm
Subject: Re: [ap-gto] Mach1 play in RA Axis - did not adjust out with Gear Mesh adjustment

Thanks for that detailed description - I found the parts as described, and when I moved the counterweight shaft, I could not see or feel any movement of the silver shaft.  The counterweight arm does still move just as before.

So my ultimate question: is it a problem that the cw shaft moves the amount shown in the video clip (attached to the first post) when the worm is engaged - with or without the clutch engaged?  I was just trying to determine that first - and then if so - how to adjust it out.  Sounds like I've reached the end of the line as far as finding the source of the play.

I'm planning to continue setting the mount up - and getting ready to take it out to the field - then I suppose I'll see if this is an issue or not when imaging.  I was just hoping to remove any source of problems in the field before I go out.

thanks,
John


Roland Christen
 

Hi John

I had one more thought while tossing and turning last night. It could be that your motor box is not fully fastened to the RA axis and thus can rock back and forth. This would be the case if the screws inside the motor box were not fully tightened by the previous owner if he took the box off in order to clean and lube the gear teeth. You might want to check that out.

To find the screws, remove the back cover that has the electronic connector. See image below.  Look inside and you will see the 2 screws that hold the gearbox to the axis (Screws marked A1, A2). These should be tight and the gearbox should be securely held in place as you wiggle the counterweight shaft.

The other two screws marked B1 and B2 attach the backstop and should also be tight. When you put the cover back on, make sure that you do not pinch any of the motor wires - very important!

Roland Christen
Astro-Physics Inc.




-----Original Message-----
From: John Davis <johncdavis200@...>
To: main@ap-gto.groups.io
Sent: Fri, Oct 2, 2020 10:22 am
Subject: Re: [ap-gto] Mach1 play in RA Axis - did not adjust out with Gear Mesh adjustment

Thanks so much for the information!  Just knowing that others have seen the issue and were able to fix it helps a lot.


John Davis
 

Hi Rowland - 
   Hope you didn't lose any sleep over this issue!  Thanks for the additional idea and detailed pictures - I just checked and all the screws there were rock-solid tight.  So that's not the source of the play.
   I have just about finished my checks of the hardware and software - got the mount talking to SGP and PHD2 - so I am hoping to get some time under the stars this week to see how the mount is working.  The only issue to solve now is that I'm used to using Polemaster to do the PA and I will need to learn another procedure to do the PA.  But I do have a RPAS so I will see how well that alone does.

  Thanks so much for all the help with debugging this problem.  Even though we haven't found it - I have learned a lot about the mount and have seen how well designed and engineered these mounts are!  

John 


John Davis
 

Wanted to circle back and provide some closure on this thread, so that if anyone comes on it searching for something similar - they will see the resolution of the issue.

The last 2 nights I was able to get out and image with this new-to-me Mach1 - still with the very slight play in the RA axis.

The conditions were clear, average seeing, below average transparency.  I had a 4 1/2 hour session the 1st night and a 4 hour session the 2nd evening. The first evening my PHD guiding averaged about .43" rms and the 2nd evening about .53" rms.  Both very good by standards of my previous mount.  There were one or two small glitches over the night - but I do not thing they were related to any play in the RA axies.  There were some fast moving small clouds moving through on the 1st night and that may explain the glitches.

So I do not think there is any issue in this mount despite the tiny bit of play that remains.

Thanks so much to Roland and others who helped me troubleshoot this issue!
John D