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Tak FS 152 objective removal for cleaning

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30 replies to this topic

#1 Rick Runcie

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Posted 21 November 2020 - 10:15 AM

I have a FS 152 that I need to remove the objective so I can clean the "rear" of the lens. I removed the dew shield, but the objective cell doesnt want to unscrew. Are there any steps I'm missing to remove it, like a locking screw or such? Any assistance would be appreciated. Thanks, Richard

#2 edif300

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Posted 21 November 2020 - 10:24 AM

If I remember well, there is a tiny lateral locking set screw in the blue ring. Try by unscrewing it firstly.



#3 edif300

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Posted 21 November 2020 - 10:34 AM

An then remove entire cell unit (blue ring + objective lens) from the main tube.



#4 Rick Runcie

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Posted 21 November 2020 - 11:28 AM

Thank you. I'll see if I can locate the set screws. Richard 



#5 Esso2112

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Posted 21 November 2020 - 01:01 PM

The set screw is really small. Mine is a flat head screw and had to use pretty much the smallest screwdriver I had.  Just did this about a month ago.  



#6 Rick Runcie

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Posted 21 November 2020 - 02:13 PM

I'm going to need a magnifying glass, I thought it looked like a tiny Allenhead. Even now when I look I cant tell. What year was your FS 152 manufactured if I may ask?

#7 SandyHouTex

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Posted 21 November 2020 - 06:23 PM

It’s also true that Tak puts a touch of clear nail polish on the screws which makes them hard to get out without stripping the heads.



#8 CHASLX200

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Posted 21 November 2020 - 06:52 PM

This is something i would never do myself.


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#9 Howard Gao

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Posted 21 November 2020 - 06:57 PM

Check it here.

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#10 Howard Gao

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Posted 21 November 2020 - 06:59 PM

I never needed to unscrew it when I removed the lense though. I suggest you check with your tak dealer for advices.


Edited by Howard Gao, 21 November 2020 - 07:11 PM.

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#11 Esso2112

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Posted 21 November 2020 - 10:39 PM

I'm going to need a magnifying glass, I thought it looked like a tiny Allenhead. Even now when I look I cant tell. What year was your FS 152 manufactured if I may ask?

Off the top of my head, I think it’s around 2002 or there about. 



#12 Rick Runcie

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Posted 22 November 2020 - 05:38 AM

Thank you all for the information.  I definitely need some magnification to see inside that small "hole". After I removed the dew shield  I made one attempt at unscrewing the objective cell, but it wouldn't budge. I then remembered reading about a set screw or such. I really am not wanting to remove it, but there is a dew spot that looks "suspicious " that I need to remove. My scope was manufactured in 2004 and has a wonderful figure.Thsnks again, Richard 



#13 SandyHouTex

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Posted 22 November 2020 - 01:13 PM

When I took my FS-152 to Tak America to get it looked over and re-collimated, when I picked it up, Fred Garcia, the wonderful technician there told me he had gone through quite a few hex wrenches to get the objective out.  He told me the trick to removing the nail polish glued Allen screws, is to heat the wrench until it’s hot enough to transfer heat to the Allen screw and melt the nail polish.  He showed me a couple that had gotten so hot that when he tried to turn them, he ended up with a hex wrench that looked like a barber poll.

 

I would never try to do this, but then I live in South of Houston and can drive my very valuable FS-152 up to Tak America.


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#14 Rick Runcie

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Posted 22 November 2020 - 02:18 PM

Living in New Jersey I wish there was a location I could take it to. Hoping it wont give me too much trouble. Thanks for that tip I might have to try it
Richard

Edited by Rick Runcie, 22 November 2020 - 03:06 PM.


#15 SandyHouTex

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Posted 22 November 2020 - 07:32 PM

Living in New Jersey I wish there was a location I could take it to. Hoping it wont give me too much trouble. Thanks for that tip I might have to try it
Richard

Good luck.


Edited by SandyHouTex, 22 November 2020 - 07:32 PM.


#16 Jim Curry

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Posted 23 November 2020 - 12:05 AM

Perhaps I’m missing something but wouldn’t there be a lot less drama to simply remove the 3 cell retaining screws, clean, replace and recollimate?


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#17 Kunama

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Posted 23 November 2020 - 02:45 AM

Perhaps I’m missing something but wouldn’t there be a lot less drama to simply remove the 3 cell retaining screws, clean, replace and recollimate?

 waytogo.gif    and if you don't adjust the 'push' screws (and orient the cell as it was) you may not even disturb the collimation....


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#18 Jim Curry

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Posted 23 November 2020 - 09:54 PM

Thank you, Matt



#19 Rick Runcie

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Posted 24 November 2020 - 09:50 AM

Jim,
I apologize for my ignorance,but could you please explain a little further which three screws your referring to? I need to remove the cell from the tube to clean the rear of the lens stack. I'm only aware of the set screw holding the cell in place to restrict unscrewing it. If there is another "easier" method, could you please explain. Best regards, Richard

#20 plyscope

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Posted 24 November 2020 - 02:41 PM

I think Jim is referring to the three sets of three at the rear of the cell.

This picture is on the Takahahshi Japan website.

 

http://www.takahashi...52/FS152K_1.JPG


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#21 Jim Curry

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Posted 24 November 2020 - 10:15 PM

Rick, Andy:

 

No, not those screws.  Look into the dew shield at the lens cell, you should see 6 screws around the perimeter of the cell. They're called the push-pull screws used to square (collimate) the lens to the optical axis.  You'll unscrew the dew shield first (this might take two people, one to hold the tube, one to unscrew the dew shield).

 

Once you've removed the three "pull" screws that hold the cell to the tube you can remove and clean the back of the lens.  If you haven't touched the "push" screws this should remain in collimation when you put the assembly back.   The push screws should be the longer of the 6 screws, not touching the cell.   You should get a collimation eyepiece to confirm.  

 

If you have any trouble understanding this PM me.

Regards,

 

Jim 



#22 Howard Gao

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Posted 24 November 2020 - 11:54 PM

FS-152 is different from other FS scopes as the screws are at the back end of the dewshield instead of the lense cell. You need to loose them first before you can take the lense off for cleaning. Here’s a photo is the FS-152 lense. By doing this the dewshield is smaller. This is why the diameter of the FS-152 dewshield is same as FS-128.

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#23 edif300

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Posted 25 November 2020 - 04:13 AM

Jim,
I apologize for my ignorance,but could you please explain a little further which three screws your referring to? I need to remove the cell from the tube to clean the rear of the lens stack. I'm only aware of the set screw holding the cell in place to restrict unscrewing it. If there is another "easier" method, could you please explain. Best regards, Richard

Rick,
The "easier" method for what you need is unscrewing lateral setscrew and removing lens cell with collimation blue ring. Use a sticker to remaing the screwing position.

After cleaning and screwing it all again to the tube, collimation will remaing very very close if not dead on.



#24 edif300

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Posted 25 November 2020 - 04:16 AM

If you find it a tricky task, a cleaning by local distributor (OU, TNR) would be best way for avoiding surprises.



#25 Jim Curry

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Posted 25 November 2020 - 07:08 AM

Rick: 

Wow, I stand corrected.  I should have gone to my office and looked at mine.  I apologize for my misinformed directions.




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