Problem Exos 2 - Small component, big impact #EXOS2


Akhet
 

Since my English in speaking and writing is rather poor due to a lack of practice, I recorded the text in German and then sent it through the Google Translator. Please forgive me.
 
First of all thanks to Robert Hoskin for his document "Notes on Tuning the EXOS-2 / PMC8 Mount Hardware". It helped me a lot in solving my problem.
 
I would like to write to you here where the problem was with me and how I could solve it. Maybe it will help one or the other with their problems.
 
In my attempts to get the backlash of my RA axis under control, I tried various tips that I found on the Internet. With the result that my guiding got worse and worse. Until it finally looked like this two days ago.
Calibration

I also noticed the following error patterns.
1. Visible oscillation of the RA axis on the star. From east to west and back to east within 20 seconds.
2. With manual control of the RA axis on the star and a short impulse to the east, the RA axis moves visibly to the west. With long impulses to the east, the RA axis moves to the east. But immediately afterwards a short impulse to the east leads to a movement to the west again.
 
Quite frustrated, I went to look for a solution again and then found Robert's document. So everything was done as described and ... no improvement. Damn.
But paragraph 7.3 got me on the track. After disassembling the worm block I could see that the ball bearings are defective. I then used suitable ball bearings (6x12x4mm) from Carson (RC Cars) as spare parts and reassembled everything. Yesterday evening with a very dense high cloud cover then another test and the result now looks like this.
Calibration

Apparently the periodic error has also decreased by replacing the ball bearings. Presumably the axis of the worm was not centered due to the defect in the ball bearings.
 
Above before below after replacing the ball bearings. The data from the picture above is from a month ago so I tried before my first adjustment.
I am very happy that it is now working again and I can now fine-tune it.
 
I hope the post will help others solve similar problems.
 
Greetings Carsten


 

Carsten,

You're most welcome - glad you were helped!

- Bob

--
Mounts: ES PMC-8 EXOS2, Serial
Scopes: SW 130P-DS, SV 102EDT, ZWO 60/280 Guide
Cameras:  Nikon D5300, Altair GPCAM2 290M
Software: ASCOM 6.3, CdC, AstroTortilla, BYN Pro, Sharpcap, PHD2
Computer:  Thinkpad x230, Win7Pro/64


Wes Mcdonald
 

Thanks Carsten!

I just ordered ceramic bearings myself.  Also some thrust bearings, which I fear will not be so good, as they have poor nn-axial load capability.  

Wes

On Thu, Mar 25, 2021 at 8:40 AM Akhet <garbage.t@...> wrote:
Since my English in speaking and writing is rather poor due to a lack of practice, I recorded the text in German and then sent it through the Google Translator. Please forgive me.
 
First of all thanks to Robert Hoskin for his document "Notes on Tuning the EXOS-2 / PMC8 Mount Hardware". It helped me a lot in solving my problem.
 
I would like to write to you here where the problem was with me and how I could solve it. Maybe it will help one or the other with their problems.
 
In my attempts to get the backlash of my RA axis under control, I tried various tips that I found on the Internet. With the result that my guiding got worse and worse. Until it finally looked like this two days ago.
Calibration

I also noticed the following error patterns.
1. Visible oscillation of the RA axis on the star. From east to west and back to east within 20 seconds.
2. With manual control of the RA axis on the star and a short impulse to the east, the RA axis moves visibly to the west. With long impulses to the east, the RA axis moves to the east. But immediately afterwards a short impulse to the east leads to a movement to the west again.
 
Quite frustrated, I went to look for a solution again and then found Robert's document. So everything was done as described and ... no improvement. Damn.
But paragraph 7.3 got me on the track. After disassembling the worm block I could see that the ball bearings are defective. I then used suitable ball bearings (6x12x4mm) from Carson (RC Cars) as spare parts and reassembled everything. Yesterday evening with a very dense high cloud cover then another test and the result now looks like this.
Calibration

Apparently the periodic error has also decreased by replacing the ball bearings. Presumably the axis of the worm was not centered due to the defect in the ball bearings.
 
Above before below after replacing the ball bearings. The data from the picture above is from a month ago so I tried before my first adjustment.
I am very happy that it is now working again and I can now fine-tune it.
 
I hope the post will help others solve similar problems.
 
Greetings Carsten


--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


Walter Vinci
 

Thanks for sharing!

Would it be possible to share the specs and from where you order these replacements? It would be good as a reference for an upgrade I might try myself in the future.

Walter

On Mar 25, 2021, at 8:29 AM, Wes Mcdonald <wesmcd6@...> wrote:


Thanks Carsten!

I just ordered ceramic bearings myself.  Also some thrust bearings, which I fear will not be so good, as they have poor nn-axial load capability.  

Wes

On Thu, Mar 25, 2021 at 8:40 AM Akhet <garbage.t@...> wrote:
Since my English in speaking and writing is rather poor due to a lack of practice, I recorded the text in German and then sent it through the Google Translator. Please forgive me.
 
First of all thanks to Robert Hoskin for his document "Notes on Tuning the EXOS-2 / PMC8 Mount Hardware". It helped me a lot in solving my problem.
 
I would like to write to you here where the problem was with me and how I could solve it. Maybe it will help one or the other with their problems.
 
In my attempts to get the backlash of my RA axis under control, I tried various tips that I found on the Internet. With the result that my guiding got worse and worse. Until it finally looked like this two days ago.
<8B0868D1-6C89-4ADE-980A-EE4AC93BBCF2.jpeg>
Calibration
<7882B30E-439D-40EC-8FF0-CD11C650F80D.jpeg>

I also noticed the following error patterns.
1. Visible oscillation of the RA axis on the star. From east to west and back to east within 20 seconds.
2. With manual control of the RA axis on the star and a short impulse to the east, the RA axis moves visibly to the west. With long impulses to the east, the RA axis moves to the east. But immediately afterwards a short impulse to the east leads to a movement to the west again.
 
Quite frustrated, I went to look for a solution again and then found Robert's document. So everything was done as described and ... no improvement. Damn.
But paragraph 7.3 got me on the track. After disassembling the worm block I could see that the ball bearings are defective. I then used suitable ball bearings (6x12x4mm) from Carson (RC Cars) as spare parts and reassembled everything. Yesterday evening with a very dense high cloud cover then another test and the result now looks like this.
<D99FB077-C2AA-426A-B072-859545BDE539.jpeg>
Calibration
<9B747EBD-79B7-482A-B988-B513F47D4510.jpeg>

Apparently the periodic error has also decreased by replacing the ball bearings. Presumably the axis of the worm was not centered due to the defect in the ball bearings.
 
Above before below after replacing the ball bearings. The data from the picture above is from a month ago so I tried before my first adjustment.
<3397A2D8-3128-4339-A0B9-F5C8321CB820.jpeg>
I am very happy that it is now working again and I can now fine-tune it.
 
I hope the post will help others solve similar problems.
 
Greetings Carsten


--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired

--
———

Walter Vinci

ES EXOS2-GT PMC-Eight
ES ED80
Starfield 0.8 Field Flattener/Reducer.
ZWO ASI290mm-mini & Orion 50mm Guide Scope
Canon EOS Rebel SL1
SharpCap, APT, PHD2, SiriL, Stellarium


Wes Mcdonald
 

Once I get them and evaluate I will post.  I believe someone else posted some time ago.

Wes


On Thu, Mar 25, 2021 at 12:14 PM Walter Vinci <wltvinci@...> wrote:
Thanks for sharing!

Would it be possible to share the specs and from where you order these replacements? It would be good as a reference for an upgrade I might try myself in the future.

Walter

On Mar 25, 2021, at 8:29 AM, Wes Mcdonald <wesmcd6@...> wrote:


Thanks Carsten!

I just ordered ceramic bearings myself.  Also some thrust bearings, which I fear will not be so good, as they have poor nn-axial load capability.  

Wes

On Thu, Mar 25, 2021 at 8:40 AM Akhet <garbage.t@...> wrote:
Since my English in speaking and writing is rather poor due to a lack of practice, I recorded the text in German and then sent it through the Google Translator. Please forgive me.
 
First of all thanks to Robert Hoskin for his document "Notes on Tuning the EXOS-2 / PMC8 Mount Hardware". It helped me a lot in solving my problem.
 
I would like to write to you here where the problem was with me and how I could solve it. Maybe it will help one or the other with their problems.
 
In my attempts to get the backlash of my RA axis under control, I tried various tips that I found on the Internet. With the result that my guiding got worse and worse. Until it finally looked like this two days ago.
<8B0868D1-6C89-4ADE-980A-EE4AC93BBCF2.jpeg>
Calibration
<7882B30E-439D-40EC-8FF0-CD11C650F80D.jpeg>

I also noticed the following error patterns.
1. Visible oscillation of the RA axis on the star. From east to west and back to east within 20 seconds.
2. With manual control of the RA axis on the star and a short impulse to the east, the RA axis moves visibly to the west. With long impulses to the east, the RA axis moves to the east. But immediately afterwards a short impulse to the east leads to a movement to the west again.
 
Quite frustrated, I went to look for a solution again and then found Robert's document. So everything was done as described and ... no improvement. Damn.
But paragraph 7.3 got me on the track. After disassembling the worm block I could see that the ball bearings are defective. I then used suitable ball bearings (6x12x4mm) from Carson (RC Cars) as spare parts and reassembled everything. Yesterday evening with a very dense high cloud cover then another test and the result now looks like this.
<D99FB077-C2AA-426A-B072-859545BDE539.jpeg>
Calibration
<9B747EBD-79B7-482A-B988-B513F47D4510.jpeg>

Apparently the periodic error has also decreased by replacing the ball bearings. Presumably the axis of the worm was not centered due to the defect in the ball bearings.
 
Above before below after replacing the ball bearings. The data from the picture above is from a month ago so I tried before my first adjustment.
<3397A2D8-3128-4339-A0B9-F5C8321CB820.jpeg>
I am very happy that it is now working again and I can now fine-tune it.
 
I hope the post will help others solve similar problems.
 
Greetings Carsten


--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired

--
———

Walter Vinci

ES EXOS2-GT PMC-Eight
ES ED80
Starfield 0.8 Field Flattener/Reducer.
ZWO ASI290mm-mini & Orion 50mm Guide Scope
Canon EOS Rebel SL1
SharpCap, APT, PHD2, SiriL, Stellarium


--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired