1200GTO servicing project notes


Dale Ghent
 

I recently took over as Observatory Director for my club's observatory and outreach center. With COVID putting a halt on the in-person outreach events that we have done on a monthly basis (and hope to return to once conditions allow), I figured now was the time to do heavy maintainence on the mount, scope, and dome.

The observatory's 1200GTO is a fairly early example and, from what we've been able to determine, has not been heavily serviced during its lifetime which is approaching 20 years old. Yep! It probably still had the original grease! Nonetheless, it has been operating fine for the most part, but it has developed some notable backlash in both axes and could use some attention so it can soldier on into the future with better performance.

The servicing tasks to be done:

1. Dismantle the mount and clean its external surfaces
2. Clean and regrease the RA and dec worm, worm wheel, and motor spur gears
3. Replace RA and Dec clutch delrin plugs
4. Polish out rust spots on CW shaft and weights and give them a nice shine (ooh pretty)
5. General inspection of mount

In addition to servicing the mount, I also wanted to install some upgrades into it for improved operation. It already had a CP4, so that only needed a firmware update. The following upgrades were chosen:

1. 1200 R.A. Motor Bracket with Spring-Loaded Action (12SLBR), Qty. 1
2. Replacement for 900/1200 Dovetail Knob (DOVEKREP), Qty. 2
3. Modified R.A. Clutch Set Screw for 1200 Mount, all models (M12668), Qty. 4

(1) was chosen to replace the original RA motor mounting bracket design with a newer version that addresses backlash better. The new bracket keeps the RA worm meshed better with the worm wheel. From what I undertand this improved bracket was standard on later 1200GTO serial numbers. It would appear that I snagged the last of this bracket at A-P, as it is now listed as out of stock and discontinued.

(2) and (3) were chosen to replace the four RA clutch knobs and two Declination axis dovetail knobs, respectively, with set screws. The 1200GTO's design predates the through-mount cabling feature found on current mount models, so any wiring coming off the scope and down the side of the mount can run the risk of snagging on one of these knobs. I've witnessed this briefly happen with ours, with the power and USB coming off the telescope getting picked up and carried briefly by one of these knobs, but the cable would free itself each time. I don't have to watch for this situation with my finger hovering over the STOP! button with these set screw replacements as the dec axis now lacks such protrusions.

Breakdown of the mount went fine save for unscrewing 1 of 5 screws that fastened the RA motor to the RA motor bracket. Despite all efforts and even a few tries with a #1 and then #2 screw extractor, the screw just would not turn. I decided that the folks at Astro-Pysics would be the best people to deal with this, so I detached the bracket from the mount body and sent the bracket+motor combination to them. Dave and their machinist went to work on it and eventually freed the screw. Upon its return, the RA motor was cleaned, greased up, and mounted on the upgraded bracket with no further issues.

Cleaning the gearing and regreasing using the Astro-Physics grease kit was easy and familiar to me, having done the same with my own Mach1 prior to this. I use flat toothpicks to gently press paper towel into the worm wheel and gear teeth which allows me gently scrape out the gummy black old grease. Cleaning the external surface of the mount was done with microfiber cloths, first with a diluted solution of citrus degreaser to get areas caked-on oil/dirt off of, then a final wipe-down with isopropyl alcohol. A little bit of elbow work got dirt and grime out of the setting circle engravings, returning the numbering and marks to their original white. We don't use them, but it makes the mount look nicer.

Replacing the delrin clutch plugs was a quick and easy. My method for extracting the old ones was to remove the clutch knob and gently tap a #1 screw extractor into the center hole of the old delrin plug, attach a tap wrench, and unscrew it out. The new delrin plugs dropped right back in to the hole.

When all the service and upgrade items were done, the mount was reassembled and the (also cleaned) TOA-150B went back on top of it. The smooth action of the unclutched axes during balancing was great, a clear difference from the sticky balky motion caused by the old delrin clutch plugs that would not fully disengage. With everything balanced and locked in, it was really nice to be greeted with a soft hum of the motors with no backlash. I now await a clear night to re-do the polar alignment using SharpCap Pro. Eventually, I want to get the club to spring for APPC Pro so we can run this with pointing and tracking models.

Throughout this project, I talked quite a bit with George, Dave, and Daleen at Astro-Physics. I can't stress how awesome they are to work with, not just on a person-to-person basis but certainly with Astro-Physics as a company. It's a rare level of service in this hobby/industry these days where things can seem kind of impersonal and faceless, and I shudder to think about what I would have to go through to get a similar level of attention with vendors of cheaper mounts, or if it would even be possible in that reality. I really want to thank them and it's why I've never hesitated in recommening their products.

I have a chronologically-ordered gallery of images from this maintenance. There's a lot of photos, so you may need to click the "Load 22 more images" button once you scroll to the bottom:

https://imgur.com/a/iDp4Qor

/dale


George
 

Dale,

So you found that the #1 extractor worked well? Did you have to do anything other than use the extractor, itself...no drilling?

Regards,

George

George Whitney
Astro-Physics, Inc.
Phone:  815-222-6538 (direct line)
Phone:  815-282-1513 (office)
Email:  george@astro-physics.com

-----Original Message-----
From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Dale Ghent
Sent: Monday, April 12, 2021 10:58 AM
To: main@ap-gto.groups.io
Subject: [ap-gto] 1200GTO servicing project notes

I recently took over as Observatory Director for my club's observatory and outreach center. With COVID putting a halt on the in-person outreach events that we have done on a monthly basis (and hope to return to once conditions allow), I figured now was the time to do heavy maintainence on the mount, scope, and dome.

The observatory's 1200GTO is a fairly early example and, from what we've been able to determine, has not been heavily serviced during its lifetime which is approaching 20 years old. Yep! It probably still had the original grease! Nonetheless, it has been operating fine for the most part, but it has developed some notable backlash in both axes and could use some attention so it can soldier on into the future with better performance.

The servicing tasks to be done:

1. Dismantle the mount and clean its external surfaces 2. Clean and regrease the RA and dec worm, worm wheel, and motor spur gears 3. Replace RA and Dec clutch delrin plugs 4. Polish out rust spots on CW shaft and weights and give them a nice shine (ooh pretty) 5. General inspection of mount

In addition to servicing the mount, I also wanted to install some upgrades into it for improved operation. It already had a CP4, so that only needed a firmware update. The following upgrades were chosen:

1. 1200 R.A. Motor Bracket with Spring-Loaded Action (12SLBR), Qty. 1 2. Replacement for 900/1200 Dovetail Knob (DOVEKREP), Qty. 2 3. Modified R.A. Clutch Set Screw for 1200 Mount, all models (M12668), Qty. 4

(1) was chosen to replace the original RA motor mounting bracket design with a newer version that addresses backlash better. The new bracket keeps the RA worm meshed better with the worm wheel. From what I undertand this improved bracket was standard on later 1200GTO serial numbers. It would appear that I snagged the last of this bracket at A-P, as it is now listed as out of stock and discontinued.

(2) and (3) were chosen to replace the four RA clutch knobs and two Declination axis dovetail knobs, respectively, with set screws. The 1200GTO's design predates the through-mount cabling feature found on current mount models, so any wiring coming off the scope and down the side of the mount can run the risk of snagging on one of these knobs. I've witnessed this briefly happen with ours, with the power and USB coming off the telescope getting picked up and carried briefly by one of these knobs, but the cable would free itself each time. I don't have to watch for this situation with my finger hovering over the STOP! button with these set screw replacements as the dec axis now lacks such protrusions.

Breakdown of the mount went fine save for unscrewing 1 of 5 screws that fastened the RA motor to the RA motor bracket. Despite all efforts and even a few tries with a #1 and then #2 screw extractor, the screw just would not turn. I decided that the folks at Astro-Pysics would be the best people to deal with this, so I detached the bracket from the mount body and sent the bracket+motor combination to them. Dave and their machinist went to work on it and eventually freed the screw. Upon its return, the RA motor was cleaned, greased up, and mounted on the upgraded bracket with no further issues.

Cleaning the gearing and regreasing using the Astro-Physics grease kit was easy and familiar to me, having done the same with my own Mach1 prior to this. I use flat toothpicks to gently press paper towel into the worm wheel and gear teeth which allows me gently scrape out the gummy black old grease. Cleaning the external surface of the mount was done with microfiber cloths, first with a diluted solution of citrus degreaser to get areas caked-on oil/dirt off of, then a final wipe-down with isopropyl alcohol. A little bit of elbow work got dirt and grime out of the setting circle engravings, returning the numbering and marks to their original white. We don't use them, but it makes the mount look nicer.

Replacing the delrin clutch plugs was a quick and easy. My method for extracting the old ones was to remove the clutch knob and gently tap a #1 screw extractor into the center hole of the old delrin plug, attach a tap wrench, and unscrew it out. The new delrin plugs dropped right back in to the hole.

When all the service and upgrade items were done, the mount was reassembled and the (also cleaned) TOA-150B went back on top of it. The smooth action of the unclutched axes during balancing was great, a clear difference from the sticky balky motion caused by the old delrin clutch plugs that would not fully disengage. With everything balanced and locked in, it was really nice to be greeted with a soft hum of the motors with no backlash. I now await a clear night to re-do the polar alignment using SharpCap Pro. Eventually, I want to get the club to spring for APPC Pro so we can run this with pointing and tracking models.

Throughout this project, I talked quite a bit with George, Dave, and Daleen at Astro-Physics. I can't stress how awesome they are to work with, not just on a person-to-person basis but certainly with Astro-Physics as a company. It's a rare level of service in this hobby/industry these days where things can seem kind of impersonal and faceless, and I shudder to think about what I would have to go through to get a similar level of attention with vendors of cheaper mounts, or if it would even be possible in that reality. I really want to thank them and it's why I've never hesitated in recommening their products.

I have a chronologically-ordered gallery of images from this maintenance. There's a lot of photos, so you may need to click the "Load 22 more images" button once you scroll to the bottom:

https://imgur.com/a/iDp4Qor

/dale


dan kowall
 

A well-done and informative pictorial, Dale.
Thanks,

dan kowall
photonhunter.com


On Monday, April 12, 2021, 11:58:33 AM EDT, Dale Ghent <daleg@...> wrote:


I recently took over as Observatory Director for my club's observatory and outreach center. With COVID putting a halt on the in-person outreach events that we have done on a monthly basis (and hope to return to once conditions allow), I figured now was the time to do heavy maintainence [sic] on the mount, scope, and dome.





Dale Ghent
 

No drilling. Just a few light taps on the extractor using a finishing nail hammer to seat the extractor bit tip into the plug's center hole, and some initial moderate downward force on the tap wrench during the first few turns to make sure it fully bit into the plug. Not hard at all.

I will note that design of the extractor bit did seem to matter. I have two #1's, one from a "Warrior" set from Harbor Freight, and another from Home Depot/Ryobi. The Ryobi bit seemed to dig in and get a bite more reliably than the Harbor Freight one. I used a Starrett 91A tap wrench.

/dale

On Apr 12, 2021, at 12:04, George <george@astro-physics.com> wrote:

Dale,

So you found that the #1 extractor worked well? Did you have to do anything other than use the extractor, itself...no drilling?

Regards,

George

George Whitney
Astro-Physics, Inc.
Phone: 815-222-6538 (direct line)
Phone: 815-282-1513 (office)
Email: george@astro-physics.com

-----Original Message-----
From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Dale Ghent
Sent: Monday, April 12, 2021 10:58 AM
To: main@ap-gto.groups.io
Subject: [ap-gto] 1200GTO servicing project notes

I recently took over as Observatory Director for my club's observatory and outreach center. With COVID putting a halt on the in-person outreach events that we have done on a monthly basis (and hope to return to once conditions allow), I figured now was the time to do heavy maintainence on the mount, scope, and dome.

The observatory's 1200GTO is a fairly early example and, from what we've been able to determine, has not been heavily serviced during its lifetime which is approaching 20 years old. Yep! It probably still had the original grease! Nonetheless, it has been operating fine for the most part, but it has developed some notable backlash in both axes and could use some attention so it can soldier on into the future with better performance.

The servicing tasks to be done:

1. Dismantle the mount and clean its external surfaces 2. Clean and regrease the RA and dec worm, worm wheel, and motor spur gears 3. Replace RA and Dec clutch delrin plugs 4. Polish out rust spots on CW shaft and weights and give them a nice shine (ooh pretty) 5. General inspection of mount

In addition to servicing the mount, I also wanted to install some upgrades into it for improved operation. It already had a CP4, so that only needed a firmware update. The following upgrades were chosen:

1. 1200 R.A. Motor Bracket with Spring-Loaded Action (12SLBR), Qty. 1 2. Replacement for 900/1200 Dovetail Knob (DOVEKREP), Qty. 2 3. Modified R.A. Clutch Set Screw for 1200 Mount, all models (M12668), Qty. 4

(1) was chosen to replace the original RA motor mounting bracket design with a newer version that addresses backlash better. The new bracket keeps the RA worm meshed better with the worm wheel. From what I undertand this improved bracket was standard on later 1200GTO serial numbers. It would appear that I snagged the last of this bracket at A-P, as it is now listed as out of stock and discontinued.

(2) and (3) were chosen to replace the four RA clutch knobs and two Declination axis dovetail knobs, respectively, with set screws. The 1200GTO's design predates the through-mount cabling feature found on current mount models, so any wiring coming off the scope and down the side of the mount can run the risk of snagging on one of these knobs. I've witnessed this briefly happen with ours, with the power and USB coming off the telescope getting picked up and carried briefly by one of these knobs, but the cable would free itself each time. I don't have to watch for this situation with my finger hovering over the STOP! button with these set screw replacements as the dec axis now lacks such protrusions.

Breakdown of the mount went fine save for unscrewing 1 of 5 screws that fastened the RA motor to the RA motor bracket. Despite all efforts and even a few tries with a #1 and then #2 screw extractor, the screw just would not turn. I decided that the folks at Astro-Pysics would be the best people to deal with this, so I detached the bracket from the mount body and sent the bracket+motor combination to them. Dave and their machinist went to work on it and eventually freed the screw. Upon its return, the RA motor was cleaned, greased up, and mounted on the upgraded bracket with no further issues.

Cleaning the gearing and regreasing using the Astro-Physics grease kit was easy and familiar to me, having done the same with my own Mach1 prior to this. I use flat toothpicks to gently press paper towel into the worm wheel and gear teeth which allows me gently scrape out the gummy black old grease. Cleaning the external surface of the mount was done with microfiber cloths, first with a diluted solution of citrus degreaser to get areas caked-on oil/dirt off of, then a final wipe-down with isopropyl alcohol. A little bit of elbow work got dirt and grime out of the setting circle engravings, returning the numbering and marks to their original white. We don't use them, but it makes the mount look nicer.

Replacing the delrin clutch plugs was a quick and easy. My method for extracting the old ones was to remove the clutch knob and gently tap a #1 screw extractor into the center hole of the old delrin plug, attach a tap wrench, and unscrew it out. The new delrin plugs dropped right back in to the hole.

When all the service and upgrade items were done, the mount was reassembled and the (also cleaned) TOA-150B went back on top of it. The smooth action of the unclutched axes during balancing was great, a clear difference from the sticky balky motion caused by the old delrin clutch plugs that would not fully disengage. With everything balanced and locked in, it was really nice to be greeted with a soft hum of the motors with no backlash. I now await a clear night to re-do the polar alignment using SharpCap Pro. Eventually, I want to get the club to spring for APPC Pro so we can run this with pointing and tracking models.

Throughout this project, I talked quite a bit with George, Dave, and Daleen at Astro-Physics. I can't stress how awesome they are to work with, not just on a person-to-person basis but certainly with Astro-Physics as a company. It's a rare level of service in this hobby/industry these days where things can seem kind of impersonal and faceless, and I shudder to think about what I would have to go through to get a similar level of attention with vendors of cheaper mounts, or if it would even be possible in that reality. I really want to thank them and it's why I've never hesitated in recommening their products.

I have a chronologically-ordered gallery of images from this maintenance. There's a lot of photos, so you may need to click the "Load 22 more images" button once you scroll to the bottom:

https://imgur.com/a/iDp4Qor

/dale









George
 

Dale,

Good info...thank you!

Regards,

George

George Whitney
Astro-Physics, Inc.
Phone:  815-222-6538 (direct line)
Phone:  815-282-1513 (office)
Email:  george@astro-physics.com

-----Original Message-----
From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Dale Ghent
Sent: Monday, April 12, 2021 11:11 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] 1200GTO servicing project notes


No drilling. Just a few light taps on the extractor using a finishing nail hammer to seat the extractor bit tip into the plug's center hole, and some initial moderate downward force on the tap wrench during the first few turns to make sure it fully bit into the plug. Not hard at all.

I will note that design of the extractor bit did seem to matter. I have two #1's, one from a "Warrior" set from Harbor Freight, and another from Home Depot/Ryobi. The Ryobi bit seemed to dig in and get a bite more reliably than the Harbor Freight one. I used a Starrett 91A tap wrench.

/dale


On Apr 12, 2021, at 12:04, George <george@astro-physics.com> wrote:

Dale,

So you found that the #1 extractor worked well? Did you have to do anything other than use the extractor, itself...no drilling?

Regards,

George

George Whitney
Astro-Physics, Inc.
Phone: 815-222-6538 (direct line)
Phone: 815-282-1513 (office)
Email: george@astro-physics.com

-----Original Message-----
From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Dale Ghent
Sent: Monday, April 12, 2021 10:58 AM
To: main@ap-gto.groups.io
Subject: [ap-gto] 1200GTO servicing project notes

I recently took over as Observatory Director for my club's observatory and outreach center. With COVID putting a halt on the in-person outreach events that we have done on a monthly basis (and hope to return to once conditions allow), I figured now was the time to do heavy maintainence on the mount, scope, and dome.

The observatory's 1200GTO is a fairly early example and, from what we've been able to determine, has not been heavily serviced during its lifetime which is approaching 20 years old. Yep! It probably still had the original grease! Nonetheless, it has been operating fine for the most part, but it has developed some notable backlash in both axes and could use some attention so it can soldier on into the future with better performance.

The servicing tasks to be done:

1. Dismantle the mount and clean its external surfaces 2. Clean and regrease the RA and dec worm, worm wheel, and motor spur gears 3. Replace RA and Dec clutch delrin plugs 4. Polish out rust spots on CW shaft and weights and give them a nice shine (ooh pretty) 5. General inspection of mount

In addition to servicing the mount, I also wanted to install some upgrades into it for improved operation. It already had a CP4, so that only needed a firmware update. The following upgrades were chosen:

1. 1200 R.A. Motor Bracket with Spring-Loaded Action (12SLBR), Qty. 1 2. Replacement for 900/1200 Dovetail Knob (DOVEKREP), Qty. 2 3. Modified R.A. Clutch Set Screw for 1200 Mount, all models (M12668), Qty. 4

(1) was chosen to replace the original RA motor mounting bracket design with a newer version that addresses backlash better. The new bracket keeps the RA worm meshed better with the worm wheel. From what I undertand this improved bracket was standard on later 1200GTO serial numbers. It would appear that I snagged the last of this bracket at A-P, as it is now listed as out of stock and discontinued.

(2) and (3) were chosen to replace the four RA clutch knobs and two Declination axis dovetail knobs, respectively, with set screws. The 1200GTO's design predates the through-mount cabling feature found on current mount models, so any wiring coming off the scope and down the side of the mount can run the risk of snagging on one of these knobs. I've witnessed this briefly happen with ours, with the power and USB coming off the telescope getting picked up and carried briefly by one of these knobs, but the cable would free itself each time. I don't have to watch for this situation with my finger hovering over the STOP! button with these set screw replacements as the dec axis now lacks such protrusions.

Breakdown of the mount went fine save for unscrewing 1 of 5 screws that fastened the RA motor to the RA motor bracket. Despite all efforts and even a few tries with a #1 and then #2 screw extractor, the screw just would not turn. I decided that the folks at Astro-Pysics would be the best people to deal with this, so I detached the bracket from the mount body and sent the bracket+motor combination to them. Dave and their machinist went to work on it and eventually freed the screw. Upon its return, the RA motor was cleaned, greased up, and mounted on the upgraded bracket with no further issues.

Cleaning the gearing and regreasing using the Astro-Physics grease kit was easy and familiar to me, having done the same with my own Mach1 prior to this. I use flat toothpicks to gently press paper towel into the worm wheel and gear teeth which allows me gently scrape out the gummy black old grease. Cleaning the external surface of the mount was done with microfiber cloths, first with a diluted solution of citrus degreaser to get areas caked-on oil/dirt off of, then a final wipe-down with isopropyl alcohol. A little bit of elbow work got dirt and grime out of the setting circle engravings, returning the numbering and marks to their original white. We don't use them, but it makes the mount look nicer.

Replacing the delrin clutch plugs was a quick and easy. My method for extracting the old ones was to remove the clutch knob and gently tap a #1 screw extractor into the center hole of the old delrin plug, attach a tap wrench, and unscrew it out. The new delrin plugs dropped right back in to the hole.

When all the service and upgrade items were done, the mount was reassembled and the (also cleaned) TOA-150B went back on top of it. The smooth action of the unclutched axes during balancing was great, a clear difference from the sticky balky motion caused by the old delrin clutch plugs that would not fully disengage. With everything balanced and locked in, it was really nice to be greeted with a soft hum of the motors with no backlash. I now await a clear night to re-do the polar alignment using SharpCap Pro. Eventually, I want to get the club to spring for APPC Pro so we can run this with pointing and tracking models.

Throughout this project, I talked quite a bit with George, Dave, and Daleen at Astro-Physics. I can't stress how awesome they are to work with, not just on a person-to-person basis but certainly with Astro-Physics as a company. It's a rare level of service in this hobby/industry these days where things can seem kind of impersonal and faceless, and I shudder to think about what I would have to go through to get a similar level of attention with vendors of cheaper mounts, or if it would even be possible in that reality. I really want to thank them and it's why I've never hesitated in recommening their products.

I have a chronologically-ordered gallery of images from this maintenance. There's a lot of photos, so you may need to click the "Load 22 more images" button once you scroll to the bottom:

https://imgur.com/a/iDp4Qor

/dale









 

thanks Dale - great info


On Mon, Apr 12, 2021 at 8:58 AM Dale Ghent <daleg@...> wrote:
I recently took over as Observatory Director for my club's observatory and outreach center. With COVID putting a halt on the in-person outreach events that we have done on a monthly basis (and hope to return to once conditions allow), I figured now was the time to do heavy maintainence on the mount, scope, and dome.

The observatory's 1200GTO is a fairly early example and, from what we've been able to determine, has not been heavily serviced during its lifetime which is approaching 20 years old. Yep! It probably still had the original grease! Nonetheless, it has been operating fine for the most part, but it has developed some notable backlash in both axes and could use some attention so it can soldier on into the future with better performance.

The servicing tasks to be done:

1. Dismantle the mount and clean its external surfaces
2. Clean and regrease the RA and dec worm, worm wheel, and motor spur gears
3. Replace RA and Dec clutch delrin plugs
4. Polish out rust spots on CW shaft and weights and give them a nice shine (ooh pretty)
5. General inspection of mount

In addition to servicing the mount, I also wanted to install some upgrades into it for improved operation. It already had a CP4, so that only needed a firmware update. The following upgrades were chosen:

1. 1200 R.A. Motor Bracket with Spring-Loaded Action (12SLBR), Qty. 1
2. Replacement for 900/1200 Dovetail Knob (DOVEKREP), Qty. 2
3. Modified R.A. Clutch Set Screw for 1200 Mount, all models (M12668), Qty. 4

(1) was chosen to replace the original RA motor mounting bracket design with a newer version that addresses backlash better. The new bracket keeps the RA worm meshed better with the worm wheel. From what I undertand this improved bracket was standard on later 1200GTO serial numbers. It would appear that I snagged the last of this bracket at A-P, as it is now listed as out of stock and discontinued.

(2) and (3) were chosen to replace the four RA clutch knobs and two Declination axis dovetail knobs, respectively, with set screws. The 1200GTO's design predates the through-mount cabling feature found on current mount models, so any wiring coming off the scope and down the side of the mount can run the risk of snagging on one of these knobs. I've witnessed this briefly happen with ours, with the power and USB coming off the telescope getting picked up and carried briefly by one of these knobs, but the cable would free itself each time. I don't have to watch for this situation with my finger hovering over the STOP! button with these set screw replacements as the dec axis now lacks such protrusions.

Breakdown of the mount went fine save for unscrewing 1 of 5 screws that fastened the RA motor to the RA motor bracket. Despite all efforts and even a few tries with a #1 and then #2 screw extractor, the screw just would not turn. I decided that the folks at Astro-Pysics would be the best people to deal with this, so I detached the bracket from the mount body and sent the bracket+motor combination to them. Dave and their machinist went to work on it and eventually freed the screw. Upon its return, the RA motor was cleaned, greased up, and mounted on the upgraded bracket with no further issues.

Cleaning the gearing and regreasing using the Astro-Physics grease kit was easy and familiar to me, having done the same with my own Mach1 prior to this. I use flat toothpicks to gently press paper towel into the worm wheel and gear teeth which allows me gently scrape out the gummy black old grease. Cleaning the external surface of the mount was done with microfiber cloths, first with a diluted solution of citrus degreaser to get areas caked-on oil/dirt off of, then a final wipe-down with isopropyl alcohol. A little bit of elbow work got dirt and grime out of the setting circle engravings, returning the numbering and marks to their original white. We don't use them, but it makes the mount look nicer.

Replacing the delrin clutch plugs was a quick and easy. My method for extracting the old ones was to remove the clutch knob and gently tap a #1 screw extractor into the center hole of the old delrin plug, attach a tap wrench, and unscrew it out. The new delrin plugs dropped right back in to the hole.

When all the service and upgrade items were done, the mount was reassembled and the (also cleaned) TOA-150B went back on top of it. The smooth action of the unclutched axes during balancing was great, a clear difference from the sticky balky motion caused by the old delrin clutch plugs that would not fully disengage. With everything balanced and locked in, it was really nice to be greeted with a soft hum of the motors with no backlash. I now await a clear night to re-do the polar alignment using SharpCap Pro. Eventually, I want to get the club to spring for APPC Pro so we can run this with pointing and tracking models.

Throughout this project, I talked quite a bit with George, Dave, and Daleen at Astro-Physics. I can't stress how awesome they are to work with, not just on a person-to-person basis but certainly with Astro-Physics as a company. It's a rare level of service in this hobby/industry these days where things can seem kind of impersonal and faceless, and I shudder to think about what I would have to go through to get a similar level of attention with vendors of cheaper mounts, or if it would even be possible in that reality. I really want to thank them and it's why I've never hesitated in recommening their products.

I have a chronologically-ordered gallery of images from this maintenance. There's a lot of photos, so you may need to click the "Load 22 more images" button once you scroll to the bottom:

https://imgur.com/a/iDp4Qor

/dale






--
Brian 



Brian Valente


sroberts84
 

Nice write up, Dale.., 
Is this the extractor you referred to that eventually worked well? 

RYOBI introduces the No.1 Spiral Screw Extractor. The RYOBI No. 1 Steel Spiral Screw Extractor features steel construction and black oxide thread for lasting performance. Use this extractor to remove screws and bolts from 1/8 in. - 1/4 in. for your convenience.
www.homedepot.com
Thanks.., 
 S Roberts 
---
We've got fifteen minutes, Freddo, it's worse than I thought!


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Dale Ghent <daleg@...>
Sent: 12 April 2021 09:10
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] 1200GTO servicing project notes
 

No drilling. Just a few light taps on the extractor using a finishing nail hammer to seat the extractor bit tip into the plug's center hole, and some initial moderate downward force on the tap wrench during the first few turns to make sure it fully bit into the plug. Not hard at all.

I will note that design of the extractor bit did seem to matter. I have two #1's, one from a "Warrior" set from Harbor Freight, and another from Home Depot/Ryobi. The Ryobi bit seemed to dig in and get a bite more reliably than the Harbor Freight one. I used a Starrett 91A tap wrench.

/dale


> On Apr 12, 2021, at 12:04, George <george@...> wrote:
>
> Dale,
>
> So you found that the #1 extractor worked well?    Did you have to do anything other than use the extractor, itself...no drilling?
>
> Regards,
>
> George
>
> George Whitney
> Astro-Physics, Inc.
> Phone:  815-222-6538 (direct line)
> Phone:  815-282-1513 (office)
> Email:  george@...
>
> -----Original Message-----
> From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Dale Ghent
> Sent: Monday, April 12, 2021 10:58 AM
> To: main@ap-gto.groups.io
> Subject: [ap-gto] 1200GTO servicing project notes
>
> I recently took over as Observatory Director for my club's observatory and outreach center. With COVID putting a halt on the in-person outreach events that we have done on a monthly basis (and hope to return to once conditions allow), I figured now was the time to do heavy maintainence on the mount, scope, and dome.
>
> The observatory's 1200GTO is a fairly early example and, from what we've been able to determine, has not been heavily serviced during its lifetime which is approaching 20 years old. Yep! It probably still had the original grease! Nonetheless, it has been operating fine for the most part, but it has developed some notable backlash in both axes and could use some attention so it can soldier on into the future with better performance.
>
> The servicing tasks to be done:
>
> 1. Dismantle the mount and clean its external surfaces 2. Clean and regrease the RA and dec worm, worm wheel, and motor spur gears 3. Replace RA and Dec clutch delrin plugs 4. Polish out rust spots on CW shaft and weights and give them a nice shine (ooh pretty) 5. General inspection of mount
>
> In addition to servicing the mount, I also wanted to install some upgrades into it for improved operation. It already had a CP4, so that only needed a firmware update. The following upgrades were chosen:
>
> 1. 1200 R.A. Motor Bracket with Spring-Loaded Action (12SLBR), Qty. 1 2. Replacement for 900/1200 Dovetail Knob (DOVEKREP), Qty. 2 3. Modified R.A. Clutch Set Screw for 1200 Mount, all models (M12668), Qty. 4
>
> (1) was chosen to replace the original RA motor mounting bracket design with a newer version that addresses backlash better. The new bracket keeps the RA worm meshed better with the worm wheel. From what I undertand this improved bracket was standard on later 1200GTO serial numbers. It would appear that I snagged the last of this bracket at A-P, as it is now listed as out of stock and discontinued.
>
> (2) and (3) were chosen to replace the four RA clutch knobs and two Declination axis dovetail knobs, respectively, with set screws. The 1200GTO's design predates the through-mount cabling feature found on current mount models, so any wiring coming off the scope and down the side of the mount can run the risk of snagging on one of these knobs. I've witnessed this briefly happen with ours, with the power and USB coming off the telescope getting picked up and carried briefly by one of these knobs, but the cable would free itself each time. I don't have to watch for this situation with my finger hovering over the STOP! button with these set screw replacements as the dec axis now lacks such protrusions.
>
> Breakdown of the mount went fine save for unscrewing 1 of 5 screws that fastened the RA motor to the RA motor bracket. Despite all efforts and even a few tries with a #1 and then #2 screw extractor, the screw just would not turn. I decided that the folks at Astro-Pysics would be the best people to deal with this, so I detached the bracket from the mount body and sent the bracket+motor combination to them. Dave and their machinist went to work on it and eventually freed the screw. Upon its return, the RA motor was cleaned, greased up, and mounted on the upgraded bracket with no further issues.
>
> Cleaning the gearing and regreasing using the Astro-Physics grease kit was easy and familiar to me, having done the same with my own Mach1 prior to this. I use flat toothpicks to gently press paper towel into the worm wheel and gear teeth which allows me gently scrape out the gummy black old grease. Cleaning the external surface of the mount was done with microfiber cloths, first with a diluted solution of citrus degreaser to get areas caked-on oil/dirt off of, then a final wipe-down with isopropyl alcohol. A little bit of elbow work got dirt and grime out of the setting circle engravings, returning the numbering and marks to their original white. We don't use them, but it makes the mount look nicer.
>
> Replacing the delrin clutch plugs was a quick and easy. My method for extracting the old ones was to remove the clutch knob and gently tap a #1 screw extractor into the center hole of the old delrin plug, attach a tap wrench, and unscrew it out. The new delrin plugs dropped right back in to the hole.
>
> When all the service and upgrade items were done, the mount was reassembled and the (also cleaned) TOA-150B went back on top of it. The smooth action of the unclutched axes during balancing was great, a clear difference from the sticky balky motion caused by the old delrin clutch plugs that would not fully disengage. With everything balanced and locked in, it was really nice to be greeted with a soft hum of the motors with no backlash. I now await a clear night to re-do the polar alignment using SharpCap Pro. Eventually, I want to get the club to spring for APPC Pro so we can run this with pointing and tracking models.
>
> Throughout this project, I talked quite a bit with George, Dave, and Daleen at Astro-Physics. I can't stress how awesome they are to work with, not just on a person-to-person basis but certainly with Astro-Physics as a company. It's a rare level of service in this hobby/industry these days where things can seem kind of impersonal and faceless, and I shudder to think about what I would have to go through to get a similar level of attention with vendors of cheaper mounts, or if it would even be possible in that reality. I really want to thank them and it's why I've never hesitated in recommening their products.
>
> I have a chronologically-ordered gallery of images from this maintenance. There's a lot of photos, so you may need to click the "Load 22 more images" button once you scroll to the bottom:
>
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fimgur.com%2Fa%2FiDp4Qor&amp;data=04%7C01%7C%7C8db9fa17e35747a6776308d8fdcd91df%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637538406636189309%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=EmbWgTXbB0DlgOvgZuCFi%2BmwURQMgPqifP0oikAGmxo%3D&amp;reserved=0
>
> /dale
>
>
>
>
>
>
>
>
>







Dale Ghent
 

Yes, that's the one.

On Apr 12, 2021, at 12:29, sroberts84 <ap-gto-group-io@outlook.com> wrote:

Nice write up, Dale..,
Is this the extractor you referred to that eventually worked well?

https://www.homedepot.com/p/RYOBI-No-1-Spiral-Screw-Extractor-A96SE61/205469313

RYOBI No.1 Spiral Screw Extractor-A96SE61 - The Home Depot
RYOBI introduces the No.1 Spiral Screw Extractor. The RYOBI No. 1 Steel Spiral Screw Extractor features steel construction and black oxide thread for lasting performance. Use this extractor to remove screws and bolts from 1/8 in. - 1/4 in. for your convenience.
www.homedepot.com
Thanks..,
S Roberts
---
We've got fifteen minutes, Freddo, it's worse than I thought!

From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Dale Ghent <daleg@elemental.org>
Sent: 12 April 2021 09:10
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] 1200GTO servicing project notes


No drilling. Just a few light taps on the extractor using a finishing nail hammer to seat the extractor bit tip into the plug's center hole, and some initial moderate downward force on the tap wrench during the first few turns to make sure it fully bit into the plug. Not hard at all.

I will note that design of the extractor bit did seem to matter. I have two #1's, one from a "Warrior" set from Harbor Freight, and another from Home Depot/Ryobi. The Ryobi bit seemed to dig in and get a bite more reliably than the Harbor Freight one. I used a Starrett 91A tap wrench.

/dale


On Apr 12, 2021, at 12:04, George <george@astro-physics.com> wrote:

Dale,

So you found that the #1 extractor worked well? Did you have to do anything other than use the extractor, itself...no drilling?

Regards,

George

George Whitney
Astro-Physics, Inc.
Phone: 815-222-6538 (direct line)
Phone: 815-282-1513 (office)
Email: george@astro-physics.com

-----Original Message-----
From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Dale Ghent
Sent: Monday, April 12, 2021 10:58 AM
To: main@ap-gto.groups.io
Subject: [ap-gto] 1200GTO servicing project notes

I recently took over as Observatory Director for my club's observatory and outreach center. With COVID putting a halt on the in-person outreach events that we have done on a monthly basis (and hope to return to once conditions allow), I figured now was the time to do heavy maintainence on the mount, scope, and dome.

The observatory's 1200GTO is a fairly early example and, from what we've been able to determine, has not been heavily serviced during its lifetime which is approaching 20 years old. Yep! It probably still had the original grease! Nonetheless, it has been operating fine for the most part, but it has developed some notable backlash in both axes and could use some attention so it can soldier on into the future with better performance.

The servicing tasks to be done:

1. Dismantle the mount and clean its external surfaces 2. Clean and regrease the RA and dec worm, worm wheel, and motor spur gears 3. Replace RA and Dec clutch delrin plugs 4. Polish out rust spots on CW shaft and weights and give them a nice shine (ooh pretty) 5. General inspection of mount

In addition to servicing the mount, I also wanted to install some upgrades into it for improved operation. It already had a CP4, so that only needed a firmware update. The following upgrades were chosen:

1. 1200 R.A. Motor Bracket with Spring-Loaded Action (12SLBR), Qty. 1 2. Replacement for 900/1200 Dovetail Knob (DOVEKREP), Qty. 2 3. Modified R.A. Clutch Set Screw for 1200 Mount, all models (M12668), Qty. 4

(1) was chosen to replace the original RA motor mounting bracket design with a newer version that addresses backlash better. The new bracket keeps the RA worm meshed better with the worm wheel. From what I undertand this improved bracket was standard on later 1200GTO serial numbers. It would appear that I snagged the last of this bracket at A-P, as it is now listed as out of stock and discontinued.

(2) and (3) were chosen to replace the four RA clutch knobs and two Declination axis dovetail knobs, respectively, with set screws. The 1200GTO's design predates the through-mount cabling feature found on current mount models, so any wiring coming off the scope and down the side of the mount can run the risk of snagging on one of these knobs. I've witnessed this briefly happen with ours, with the power and USB coming off the telescope getting picked up and carried briefly by one of these knobs, but the cable would free itself each time. I don't have to watch for this situation with my finger hovering over the STOP! button with these set screw replacements as the dec axis now lacks such protrusions.

Breakdown of the mount went fine save for unscrewing 1 of 5 screws that fastened the RA motor to the RA motor bracket. Despite all efforts and even a few tries with a #1 and then #2 screw extractor, the screw just would not turn. I decided that the folks at Astro-Pysics would be the best people to deal with this, so I detached the bracket from the mount body and sent the bracket+motor combination to them. Dave and their machinist went to work on it and eventually freed the screw. Upon its return, the RA motor was cleaned, greased up, and mounted on the upgraded bracket with no further issues.

Cleaning the gearing and regreasing using the Astro-Physics grease kit was easy and familiar to me, having done the same with my own Mach1 prior to this. I use flat toothpicks to gently press paper towel into the worm wheel and gear teeth which allows me gently scrape out the gummy black old grease. Cleaning the external surface of the mount was done with microfiber cloths, first with a diluted solution of citrus degreaser to get areas caked-on oil/dirt off of, then a final wipe-down with isopropyl alcohol. A little bit of elbow work got dirt and grime out of the setting circle engravings, returning the numbering and marks to their original white. We don't use them, but it makes the mount look nicer.

Replacing the delrin clutch plugs was a quick and easy. My method for extracting the old ones was to remove the clutch knob and gently tap a #1 screw extractor into the center hole of the old delrin plug, attach a tap wrench, and unscrew it out. The new delrin plugs dropped right back in to the hole.

When all the service and upgrade items were done, the mount was reassembled and the (also cleaned) TOA-150B went back on top of it. The smooth action of the unclutched axes during balancing was great, a clear difference from the sticky balky motion caused by the old delrin clutch plugs that would not fully disengage. With everything balanced and locked in, it was really nice to be greeted with a soft hum of the motors with no backlash. I now await a clear night to re-do the polar alignment using SharpCap Pro. Eventually, I want to get the club to spring for APPC Pro so we can run this with pointing and tracking models.

Throughout this project, I talked quite a bit with George, Dave, and Daleen at Astro-Physics. I can't stress how awesome they are to work with, not just on a person-to-person basis but certainly with Astro-Physics as a company. It's a rare level of service in this hobby/industry these days where things can seem kind of impersonal and faceless, and I shudder to think about what I would have to go through to get a similar level of attention with vendors of cheaper mounts, or if it would even be possible in that reality. I really want to thank them and it's why I've never hesitated in recommening their products.

I have a chronologically-ordered gallery of images from this maintenance. There's a lot of photos, so you may need to click the "Load 22 more images" button once you scroll to the bottom:

https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fimgur.com%2Fa%2FiDp4Qor&;data=04%7C01%7C%7C8db9fa17e35747a6776308d8fdcd91df%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637538406636189309%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=EmbWgTXbB0DlgOvgZuCFi%2BmwURQMgPqifP0oikAGmxo%3D&amp;reserved=0

/dale














sroberts84
 

Great, thanks for confirming, Dale! 

---
We've got fifteen minutes, Freddo, it's worse than I thought!


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Dale Ghent <daleg@...>
Sent: 12 April 2021 09:31
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] 1200GTO servicing project notes
 

Yes, that's the one.

> On Apr 12, 2021, at 12:29, sroberts84 <ap-gto-group-io@...> wrote:
>
> Nice write up, Dale..,
> Is this the extractor you referred to that eventually worked well?
>
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.homedepot.com%2Fp%2FRYOBI-No-1-Spiral-Screw-Extractor-A96SE61%2F205469313&amp;data=04%7C01%7C%7Cab2491b97602465306ef08d8fdd06f39%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637538418959926485%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=sKG%2B9jM1QnUrluUjO%2FR%2F1zr5HoC882myypI5DC0qo28%3D&amp;reserved=0
>
> RYOBI No.1 Spiral Screw Extractor-A96SE61 - The Home Depot
> RYOBI introduces the No.1 Spiral Screw Extractor. The RYOBI No. 1 Steel Spiral Screw Extractor features steel construction and black oxide thread for lasting performance. Use this extractor to remove screws and bolts from 1/8 in. - 1/4 in. for your convenience.
> https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.homedepot.com%2F&amp;data=04%7C01%7C%7Cab2491b97602465306ef08d8fdd06f39%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637538418959936479%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=0mufXoIrQ4YpVGiwpbGzSMfZOXtPPcrB9FUPRG6A21s%3D&amp;reserved=0
> Thanks..,
>  S Roberts
> ---
> We've got fifteen minutes, Freddo, it's worse than I thought!
>
> From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Dale Ghent <daleg@...>
> Sent: 12 April 2021 09:10
> To: main@ap-gto.groups.io <main@ap-gto.groups.io>
> Subject: Re: [ap-gto] 1200GTO servicing project notes
>
>
> No drilling. Just a few light taps on the extractor using a finishing nail hammer to seat the extractor bit tip into the plug's center hole, and some initial moderate downward force on the tap wrench during the first few turns to make sure it fully bit into the plug. Not hard at all.
>
> I will note that design of the extractor bit did seem to matter. I have two #1's, one from a "Warrior" set from Harbor Freight, and another from Home Depot/Ryobi. The Ryobi bit seemed to dig in and get a bite more reliably than the Harbor Freight one. I used a Starrett 91A tap wrench.
>
> /dale
>
>
> > On Apr 12, 2021, at 12:04, George <george@...> wrote:
> >
> > Dale,
> >
> > So you found that the #1 extractor worked well?    Did you have to do anything other than use the extractor, itself...no drilling?
> >
> > Regards,
> >
> > George
> >
> > George Whitney
> > Astro-Physics, Inc.
> > Phone:  815-222-6538 (direct line)
> > Phone:  815-282-1513 (office)
> > Email:  george@...
> >
> > -----Original Message-----
> > From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Dale Ghent
> > Sent: Monday, April 12, 2021 10:58 AM
> > To: main@ap-gto.groups.io
> > Subject: [ap-gto] 1200GTO servicing project notes
> >
> > I recently took over as Observatory Director for my club's observatory and outreach center. With COVID putting a halt on the in-person outreach events that we have done on a monthly basis (and hope to return to once conditions allow), I figured now was the time to do heavy maintainence on the mount, scope, and dome.
> >
> > The observatory's 1200GTO is a fairly early example and, from what we've been able to determine, has not been heavily serviced during its lifetime which is approaching 20 years old. Yep! It probably still had the original grease! Nonetheless, it has been operating fine for the most part, but it has developed some notable backlash in both axes and could use some attention so it can soldier on into the future with better performance.
> >
> > The servicing tasks to be done:
> >
> > 1. Dismantle the mount and clean its external surfaces 2. Clean and regrease the RA and dec worm, worm wheel, and motor spur gears 3. Replace RA and Dec clutch delrin plugs 4. Polish out rust spots on CW shaft and weights and give them a nice shine (ooh pretty) 5. General inspection of mount
> >
> > In addition to servicing the mount, I also wanted to install some upgrades into it for improved operation. It already had a CP4, so that only needed a firmware update. The following upgrades were chosen:
> >
> > 1. 1200 R.A. Motor Bracket with Spring-Loaded Action (12SLBR), Qty. 1 2. Replacement for 900/1200 Dovetail Knob (DOVEKREP), Qty. 2 3. Modified R.A. Clutch Set Screw for 1200 Mount, all models (M12668), Qty. 4
> >
> > (1) was chosen to replace the original RA motor mounting bracket design with a newer version that addresses backlash better. The new bracket keeps the RA worm meshed better with the worm wheel. From what I undertand this improved bracket was standard on later 1200GTO serial numbers. It would appear that I snagged the last of this bracket at A-P, as it is now listed as out of stock and discontinued.
> >
> > (2) and (3) were chosen to replace the four RA clutch knobs and two Declination axis dovetail knobs, respectively, with set screws. The 1200GTO's design predates the through-mount cabling feature found on current mount models, so any wiring coming off the scope and down the side of the mount can run the risk of snagging on one of these knobs. I've witnessed this briefly happen with ours, with the power and USB coming off the telescope getting picked up and carried briefly by one of these knobs, but the cable would free itself each time. I don't have to watch for this situation with my finger hovering over the STOP! button with these set screw replacements as the dec axis now lacks such protrusions.
> >
> > Breakdown of the mount went fine save for unscrewing 1 of 5 screws that fastened the RA motor to the RA motor bracket. Despite all efforts and even a few tries with a #1 and then #2 screw extractor, the screw just would not turn. I decided that the folks at Astro-Pysics would be the best people to deal with this, so I detached the bracket from the mount body and sent the bracket+motor combination to them. Dave and their machinist went to work on it and eventually freed the screw. Upon its return, the RA motor was cleaned, greased up, and mounted on the upgraded bracket with no further issues.
> >
> > Cleaning the gearing and regreasing using the Astro-Physics grease kit was easy and familiar to me, having done the same with my own Mach1 prior to this. I use flat toothpicks to gently press paper towel into the worm wheel and gear teeth which allows me gently scrape out the gummy black old grease. Cleaning the external surface of the mount was done with microfiber cloths, first with a diluted solution of citrus degreaser to get areas caked-on oil/dirt off of, then a final wipe-down with isopropyl alcohol. A little bit of elbow work got dirt and grime out of the setting circle engravings, returning the numbering and marks to their original white. We don't use them, but it makes the mount look nicer.
> >
> > Replacing the delrin clutch plugs was a quick and easy. My method for extracting the old ones was to remove the clutch knob and gently tap a #1 screw extractor into the center hole of the old delrin plug, attach a tap wrench, and unscrew it out. The new delrin plugs dropped right back in to the hole.
> >
> > When all the service and upgrade items were done, the mount was reassembled and the (also cleaned) TOA-150B went back on top of it. The smooth action of the unclutched axes during balancing was great, a clear difference from the sticky balky motion caused by the old delrin clutch plugs that would not fully disengage. With everything balanced and locked in, it was really nice to be greeted with a soft hum of the motors with no backlash. I now await a clear night to re-do the polar alignment using SharpCap Pro. Eventually, I want to get the club to spring for APPC Pro so we can run this with pointing and tracking models.
> >
> > Throughout this project, I talked quite a bit with George, Dave, and Daleen at Astro-Physics. I can't stress how awesome they are to work with, not just on a person-to-person basis but certainly with Astro-Physics as a company. It's a rare level of service in this hobby/industry these days where things can seem kind of impersonal and faceless, and I shudder to think about what I would have to go through to get a similar level of attention with vendors of cheaper mounts, or if it would even be possible in that reality. I really want to thank them and it's why I've never hesitated in recommening their products.
> >
> > I have a chronologically-ordered gallery of images from this maintenance. There's a lot of photos, so you may need to click the "Load 22 more images" button once you scroll to the bottom:
> >
> > https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fimgur.com%2Fa%2FiDp4Qor&amp;data=04%7C01%7C%7Cab2491b97602465306ef08d8fdd06f39%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637538418959936479%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=YP7Kd7eFA%2FDfHcKIjdYitpPR2u%2FYxgyLNNJJswVPgU0%3D&amp;reserved=0
> >
> > /dale
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>
>
>
>
>
>







Karen Christen
 

Thanks for sharing your project with us, Dale!  Everything looks so nice now.  And yeah, we think Dave, Daleen, and George are pretty awesome, too.  😊

Karen

 

-----Original Message-----
From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Dale Ghent
Sent: Monday, April 12, 2021 10:58 AM
To: main@ap-gto.groups.io
Subject: [ap-gto] 1200GTO servicing project notes

 

I recently took over as Observatory Director for my club's observatory and outreach center. With COVID putting a halt on the in-person outreach events that we have done on a monthly basis (and hope to return to once conditions allow), I figured now was the time to do heavy maintainence on the mount, scope, and dome.

 

The observatory's 1200GTO is a fairly early example and, from what we've been able to determine, has not been heavily serviced during its lifetime which is approaching 20 years old. Yep! It probably still had the original grease! Nonetheless, it has been operating fine for the most part, but it has developed some notable backlash in both axes and could use some attention so it can soldier on into the future with better performance.

 

The servicing tasks to be done:

 

1. Dismantle the mount and clean its external surfaces 2. Clean and regrease the RA and dec worm, worm wheel, and motor spur gears 3. Replace RA and Dec clutch delrin plugs 4. Polish out rust spots on CW shaft and weights and give them a nice shine (ooh pretty) 5. General inspection of mount

 

In addition to servicing the mount, I also wanted to install some upgrades into it for improved operation. It already had a CP4, so that only needed a firmware update. The following upgrades were chosen:

 

1. 1200 R.A. Motor Bracket with Spring-Loaded Action (12SLBR), Qty. 1 2. Replacement for 900/1200 Dovetail Knob (DOVEKREP), Qty. 2 3. Modified R.A. Clutch Set Screw for 1200 Mount, all models (M12668), Qty. 4

 

(1) was chosen to replace the original RA motor mounting bracket design with a newer version that addresses backlash better. The new bracket keeps the RA worm meshed better with the worm wheel. From what I undertand this improved bracket was standard on later 1200GTO serial numbers. It would appear that I snagged the last of this bracket at A-P, as it is now listed as out of stock and discontinued.

 

(2) and (3) were chosen to replace the four RA clutch knobs and two Declination axis dovetail knobs, respectively, with set screws. The 1200GTO's design predates the through-mount cabling feature found on current mount models, so any wiring coming off the scope and down the side of the mount can run the risk of snagging on one of these knobs. I've witnessed this briefly happen with ours, with the power and USB coming off the telescope getting picked up and carried briefly by one of these knobs, but the cable would free itself each time. I don't have to watch for this situation with my finger hovering over the STOP! button with these set screw replacements as the dec axis now lacks such protrusions.

 

Breakdown of the mount went fine save for unscrewing 1 of 5 screws that fastened the RA motor to the RA motor bracket. Despite all efforts and even a few tries with a #1 and then #2 screw extractor, the screw just would not turn. I decided that the folks at Astro-Pysics would be the best people to deal with this, so I detached the bracket from the mount body and sent the bracket+motor combination to them. Dave and their machinist went to work on it and eventually freed the screw. Upon its return, the RA motor was cleaned, greased up, and mounted on the upgraded bracket with no further issues.

 

Cleaning the gearing and regreasing using the Astro-Physics grease kit was easy and familiar to me, having done the same with my own Mach1 prior to this. I use flat toothpicks to gently press paper towel into the worm wheel and gear teeth which allows me gently scrape out the gummy black old grease. Cleaning the external surface of the mount was done with microfiber cloths, first with a diluted solution of citrus degreaser to get areas caked-on oil/dirt off of, then a final wipe-down with isopropyl alcohol. A little bit of elbow work got dirt and grime out of the setting circle engravings, returning the numbering and marks to their original white. We don't use them, but it makes the mount look nicer.

 

Replacing the delrin clutch plugs was a quick and easy. My method for extracting the old ones was to remove the clutch knob and gently tap a #1 screw extractor into the center hole of the old delrin plug, attach a tap wrench, and unscrew it out. The new delrin plugs dropped right back in to the hole.

 

When all the service and upgrade items were done, the mount was reassembled and the (also cleaned) TOA-150B went back on top of it. The smooth action of the unclutched axes during balancing was great, a clear difference from the sticky balky motion caused by the old delrin clutch plugs that would not fully disengage. With everything balanced and locked in, it was really nice to be greeted with a soft hum of the motors with no backlash. I now await a clear night to re-do the polar alignment using SharpCap Pro. Eventually, I want to get the club to spring for APPC Pro so we can run this with pointing and tracking models.

 

Throughout this project, I talked quite a bit with George, Dave, and Daleen at Astro-Physics. I can't stress how awesome they are to work with, not just on a person-to-person basis but certainly with Astro-Physics as a company. It's a rare level of service in this hobby/industry these days where things can seem kind of impersonal and faceless, and I shudder to think about what I would have to go through to get a similar level of attention with vendors of cheaper mounts, or if it would even be possible in that reality. I really want to thank them and it's why I've never hesitated in recommening their products.

 

I have a chronologically-ordered gallery of images from this maintenance. There's a lot of photos, so you may need to click the "Load 22 more images" button once you scroll to the bottom:

 

https://imgur.com/a/iDp4Qor

 

/dale

 

 

 


--
Karen Christen
Astro-Physics


Andrew J
 
Edited

Hi Dale.

Thanks for sharing the photos. Very helpful. What did you use to clean the the Worm and and Worm Wheel?


Dale Ghent
 

On Apr 12, 2021, at 13:43, Andrew Jones <andjones132@gmail.com> wrote:

Hi Dale.

Thanks for sharing the photos. Very helpful. What did you use to clean the the Worm and and Worm Wheel?
I use 3 things:

* An old white cotton rag, t-shirt, or similar
* A roll of regular paper towels or shop paper towels (the blue kind you can get at auto stores)
* A box of flat toothpicks

Given the nature of the work, it's tedious. The 1200 was much easier to clean compared to my Mach1 because the worm wheel teeth are larger. Either way, be prepared for a time-consuming process and relax while you do it, because your fingers will get tried if you don't.

For the worm wheel:

1. Use cotton rag to wipe old grease from the surface of the whole worm wheel. This will leave you with a shiny wheel with dirty teeth.

2. Get a square of paper towel and a flat toothpick and start on cleaning out the teeth (valleys?) in the worm wheel. Put a part of the paper towel over the teeth and push it into one of the teeth with the broad end of the flat toothpick. Start at one end and, with one hand holding the paper towel and the other hand holding the toothpick, start at one end of the tooth and make a single wiping motion with the toothpick+towel along its length to the other end.

You want the towel and toothpick to move together, not let the toothpick slide over the towel. This will pick up and push any gunk out. For larger/deeper/wider teeth such as ones on the RA wheel, you might want to fold the paper towel over on itself and do it with two layers. The flat toothpicks work well because you can adjust the angle of the broad end such that it's pressing the paper towel against the sides and bottom of the tooth at the same time. I found with this method that I rarely need to do a tooth twice, if the grease isn't hardened.

3. One all teeth or a section of teeth on the wheel are cleaned, wipe it down again with the cotton rag.

4. Once completely done with the wheel, shine a light on it and give it a few spins as you watch for any darker teeth to spin by. It's a decent way to quickly find any teeth that might still have a little smear of old dirty grease in them. Go back with the paper towel+toothpick and clean out any that show up.

I found that using the cotton rag for wiping down the surface and the paper tow for the in-tooth work to be a good combo. The edges of the teeth on these wheels are sharp and I've found they can chew up a cotton rag pretty quickly, leaving little cotton bits everywhere. Using paper towel seems to avoid this issue.

For the worm gear, there are two ways to do it. One is while the spur gears are out so that the worm gear can freely rotate as you clean it. Another is with the spur gears in and the motor attached to the RA plug of the cable and powered on, with the worm being rotated by the motor at a custom tracking rate that's (subjectively) faster than sidereal. Otherwise, the method is similar to the worm wheel with the use of cotton rag, paper towel, and toothpick.

1. Wipe down surface of the worm gear and remove excess grease with cotton rag

2. Take paper towel+toothpick and press the towel into the groove, scooping out gunk as it turns

3. Further wipe down and touch up as needed until clean


Then apply grease per the instructions (I went a little heavy on the grease in my photos; it's going to be in a non-conditioned space and it might be a while until the next regreasing). Also, bring a box of flat toothpicks, not just a few. They'll snap and break as you do it. Just toss them aside and grab another one as you go along. I'm thinking a plastic implement of similar design would fare better here, perhaps made out of pvc or styrene, but given the cost of toothpicks, it's no a big deal.

/dale


fernandorivera3
 

This particular item has more negative reviews than positive- buyer beware!!

Fernando


Dale Ghent
 

I'm sorry, what are you referring to?

On Apr 22, 2021, at 10:35, fernandorivera3 via groups.io <fernandorivera3=yahoo.com@groups.io> wrote:

This particular item has more negative reviews than positive- buyer beware!!

Fernando


M Hambrick
 

Fernando

Are you referring to the screw extractor ? Those are all very very tricky to use.

Mike


fernandorivera3
 

Dale it was a Ryobi item from Home Depot & the link was posted to the group maybe 10 days ago or so <yes it takes me a while to reply to messages due to heavy work schedule>. I believe the product was for removal of the delrin clutch plugs among other things, IIRC.

Fernando


Dale Ghent
 

Ah, you left out the context in your reply so it was unknown what you were referring to.

The Ryobi bits worked well for me, so I can speak only for my experience. I used the #1 extractor to remove all 8 of the delrin plugs on the 1200GTO that I serviced. A few light taps with a hammer to first seat the bit and then turning with a tap wrench was all that was required. If you do not have a tap wrench then an adjustable wrench or vice grips can serve as an awkward stand-in. But if you have extractors, you should really have a tap wrench that fits them for them to work well.

This is not to say that Ryobi bits are the only ones that will work for this task, of course. In my case, they worked better than the other brand I had from Harbor Freight.

On Apr 22, 2021, at 12:28, fernandorivera3 via groups.io <fernandorivera3=yahoo.com@groups.io> wrote:

Dale it was a Ryobi item from Home Depot & the link was posted to the group maybe 10 days ago or so <yes it takes me a while to reply to messages due to heavy work schedule>. I believe the product was for removal of the delrin clutch plugs among other things, IIRC.

Fernando


M Hambrick
 

I expect that both the Ryobi and Harbor Freight extractors both come from China, but there are degrees of badness. Since they are a well known brand, I expect that the Ryobi extractors are held to a higher standard than the ones from Harbor Freight.

As a policy I don't trust anything from China, but especially anything that requires reliable metallurgy like drills, taps, and screw extractors. All of these cutting tools have to ride knife edge between hardness and brittleness. American made cutting tools can still be had from companies like Morse, Union / Butterfield, Niagara, and Cleveland Twist Drill, but you are going to pay a lot more for them.

Mike


fernandorivera3
 

Dale thanks for commenting. I have a 1200 GTO that I bought brand new from AP in July 2009. No problems yet with delrin clutch plugs getting stuck or seized & hoping it stays that way 🤞

Fernando


fernandorivera3
 

Mike- yes, correct it was the screw extractor I was talking about. Have not used one of those yet. 

Fernando