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CEM60 Polar Scope shifting

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12 replies to this topic

#1 Mike 200K

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Posted 16 February 2019 - 05:19 PM

When checking scope/ polar axis alignment i found the reason for my terrible primary alignments: the polar scope shifts left to right by about 40' (!). First I suspected the locking screws behind that electric panel, but they are tight, seems the plate carrying the scope is the culprit.

 

This area is difficult to access due to the electronics living there, but somebody may have run into the same problem?

 

I already contacted vendor and iOptron, but I would like to get this tied up before Monday...

 

Thanks for any suggestion you have

 

Michael


Edited by Mike 200K, 16 February 2019 - 05:20 PM.


#2 Mike 200K

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Posted 16 February 2019 - 07:26 PM

and that is the culprit: I finally got brave and pulled the polar scope, which allowed me to dislodge the double PCB. Then it became obvious that the sleeve to the left of the arrow (which indicates the moving gap) is moving. It is not obvious if this item is press-fit like morse-taper, or has some hidden set screws... waiting for someone who knows, here or with iOptron...

Attached Thumbnails

  • CEM 60 polar scope carrier.jpg

Edited by Mike 200K, 16 February 2019 - 07:27 PM.


#3 Hilbily

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Posted 17 February 2019 - 03:10 AM

There are three screws that center the polar scope on axis, that was my problem with the polar alignment being off. Didn’t notice anything loose.

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Edited by Hilbily, 17 February 2019 - 03:16 AM.


#4 Destrehan Dave

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Posted 17 February 2019 - 12:37 PM

Probably not what you were looking for, but after hours of tweaking the polar scope, I yanked it out, put it in a nox on a shelf, got a PoleMaster, ran extra wires thru the mount, and never looked back.

I wish it was removable, like the AP RAPAS.

DD

#5 Mike 200K

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Posted 19 February 2019 - 02:12 PM

completed that fix, and it was very interesting, fun and successful. Made me appreciate the quality of the build of that CEM60, and my opinion will not change because of one loose set screw.

 

If there is any interest I will post a few pointers and pictures. Was also able to perfectly align scope to RA axis, cannot wait to test this on Polaris. Of course its raining here for the next 2-3 days

 

The reticle alignment procedure is quite simple BTW, and if I can do it, everybody can...

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#6 arivas

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Posted 19 February 2019 - 02:27 PM

....

If there is any interest I will post a few pointers and pictures. Was also able to perfectly align scope to RA axis, cannot wait to test this on Polaris. Of course its raining here for the next 2-3 days

 

 

...

Good to see you solved this without a lot of drama, I'm receiving one of this today, so would appreciate the pointers, just in case...! (Anyways this might be useful if at some point I have to re-assemble the polar scope, just thinking!)

best regards,

 

Antonio Rivas



#7 Mike 200K

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Posted 20 February 2019 - 08:51 AM

1.jpg

 

Here is what I did:

 

(I am an amateur, and proceeded with guidance from iOptron technicians. Whatever you do to your mount, proceed with caution and always consider the possibility that I could be totally NUTS. Or a total FRAUD. Whatever you do, you do it at your own risk.)

 

In this image we are looking at three main players: Most prominently the black Polar Scope Adapter (1) which was not adequately secured in my mount. One of the set screws holding the polar scope is visible next to the red (1).This adapter has 3 different “windows” to allow three different cables to pass to the “electronic sandwich”, which I had mobilized enough to pull away from the mount, and to the left in this pic.

 

The Polar Scope Adapter is secured with 2 set-screws in the silvery-grey RA axis element (2). These Set screws however are inaccessible, as they are covered by the black Locking Ring (3). This ring is threaded onto the RA axis, and is secured to (2) by a singular 2mm locking screw (visible next to the red number (3).) This locking ring is extremely important, as the position of that ring controls the bearing preload of the main bearings of RA-axis.

 

Therefore it is probably the most important step in this entire procedure to accurately record the position of this bearing tensioning ring.


Edited by Mike 200K, 20 February 2019 - 11:18 AM.


#8 Mike 200K

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Posted 20 February 2019 - 09:11 AM

Straight and curved 5" hemostat clamps are super helpful in mobilizing and moving the wires through the adapter windows to pull the "electronic sandwich" further away from the mount.  The edges of these openings are quite sharp and will easily damage or cut the insulation of these wires, so I took some time to "lift" the wires through these windows.

 

This step is necessary to gain access to three screws for disassembly of PCB from its black cover plate. Only now one can unplug the cables (best done with hemostat also) and disconnect the red and black power cables. Note polarity, obviously...

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  • 2.jpg


#9 Mike 200K

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Posted 20 February 2019 - 09:30 AM

To remove the Locking ring we first have to unscrew a singular 2mm Set Screw. The space above this screw is quite tight, your regular Allen-wrench will not fit into that space. So I was off to my favorite local hardware store and spent 4 bucks on a cheap metric Allen wrench set, and sacrificed the 1.5, and also the 2.0mm wrench to modify them for our purpose. 

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  • 3.jpg


#10 Mike 200K

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Posted 20 February 2019 - 09:34 AM

4.jpg

 

The 1.5mm will bend, the 2mm will break under this treatment. I used a Dremel tool to cut the 2mm wrench to size, and grind it's business end 


Edited by Mike 200K, 20 February 2019 - 09:36 AM.


#11 Mike 200K

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Posted 20 February 2019 - 09:50 AM

Removal of the set screw. Now the locking ring can be unthreaded to gain access to the 1.5mm locking screws that are holding the polar scope adapter.

 

 

5.jpg

 

 

Before moving that ring its EXACT position has to be recorded. I marked the spots adjacent to 2 holes in the ring, likely wrench attachment points.

 

6.jpg



#12 Mike 200K

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Posted 20 February 2019 - 04:53 PM

The locking ring is not on very tightly, and just a few light taps with a large Phillips head screwdriver loosened it. was removed without problems. On a side note: I kept all the goodies retrieved in that green plastic box.

 

That it is green seems to be important.

 

Important also, that after reassembly I had only tools left.

 

 

8.jpg

 

 



#13 Mike 200K

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Posted 20 February 2019 - 05:41 PM

From here on it was easy: the retrieval of the adapter was a cinch of course, and yes, one of the 2 set screws was not tightened. after a quick inspection, no other problems noted, I reset the adapter and tightened both of the 2 (two) set screws. Successfully. That thing is stable now. Re-assembly is quick and simple, the only tricky part is the proper adjustment of the locking ring, it became finger tight about 180 degrees before "home" and again, using a small hammer and a screw driver I tapped it until my mark and that hole in the ring matched up. A quick check "how does it feel" to swing the mount about the RA axis? not stiff, and not loose, and no free radial play. According to Ioptron that's what you want. I pulled the cables through "their" windows in the adapter, and made sure I did not create a wire-braid behind the window.

 

Then I connected the mount and let it find "zero position" before inserting and setting the polar scope, to make sure reticle 12 o'clock is really @12.

 

The subsequent polar scope alignment with RA axis went according to the instruction posted above, and it is best done at this point, with the PCB/ cover plate out of the way.

 

Reconnecting and putting the "electronic sandwich" back requires that one pushes the cables/ wires back into the space behind the adapter, I used the hemostat clamps to do this carefully. Nonetheless, specifically the shrink tube around the USB cable looked beat up despite all my efforts, so I checked that before closing up.

 

Reattaching the reticle-LED: don't forget/ loose that mini spacer.

 

Before setting the little bubble level, again let the mount find zero.

 

Thats all, folks.




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