BYoesle
Post Laureate
Reged: 06/12/04
Posts: 3510
Loc: Washington USA
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Has anyone disassembled their Questar control box to make minor adjustments or repairs? I purchased a used Questar a couple of years ago, which had been recently serviced just prior to my buying it. It has worked fine when I used it during the warm months, but the other night when observing Mars the images were noticeably astigmatic. I think the cold weather may have affected a retaining clip or something else may have become loose, and I'd like to inspect for any problems before the expense of a return to Q land.
Any input would be much appreciated.
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Bob  diagonally parked in a parallel universe...
Your heart is free. Have the courage to follow it.
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JimK
professor emeritus
Reged: 09/18/05
Posts: 635
Loc: Albuquerque, NM USA
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Opening the control box seems easy, remove the axial port cover (you'll see why next post), the focus knob (0.060 inch 6-spline bristol setscrew), and four 5/64-inch allen head screws. The attached photo shows which ones. HOWEVER, there is something to watch for... (see next post).
Disclaimer - proceed at your own risk. I'm not a Questar service person nor Questar expert.
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JimK
professor emeritus
Reged: 09/18/05
Posts: 635
Loc: Albuquerque, NM USA
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The finder lever inside the control box is slid out of a black plate, and the plate is spring-loaded. Use a small wood stick to control these items as the control box is removed. See attached photo for pin/plate area as viewed via axial port.
Disclaimer - proceed at your own risk. I'm not a Questar service person nor Questar expert.
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JimK
professor emeritus
Reged: 09/18/05
Posts: 635
Loc: Albuquerque, NM USA
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There's not much that I can see to adjust inside the control port cover, shown in the attached photo. The barlow lens assembly is attached to a sliding brass plate via two screws and a metal band/"rubber" gasket arrangement.
Disclaimer - proceed at your own risk. I'm not a Questar service person nor Questar expert.
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JimK
professor emeritus
Reged: 09/18/05
Posts: 635
Loc: Albuquerque, NM USA
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Here is the view once the control box cover is removed. There are two screws that retain (& somewhat align) the diagonal prism. A limited amount of thread on the screws restricts the thickness of cork shims that can be used to move the prism to the right.
HOWEVER, it would seem that collimation of the diagonal prism is not for "first-timers" without the optical equipment and patience.
This is about the extent of the information that I can offer on the inside of a recent Questar standard control box.
Disclaimer - proceed at your own risk. I'm not a Questar service person nor Questar expert.
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Mapman
member
Reged: 09/08/06
Posts: 45
Loc: Kansas
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JimK,
Re: Disassembly Instructions
"You're a braver man than I am, Gunga Din,"
Thanks for the photos,
Dave
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GR1973
super member
Reged: 09/29/07
Posts: 121
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OOOh you are the most brave man deals with Questar ....I have two questaions:
1-What is the benefit of O ring rubber ???
2-second can you post a close micro photo of your declination lock knob to compare with mine because i have
one scratch beside both screws that tight the knob to the bar of declination lock ...I want to know if this originally normal with a new scope or not???
Many thanks and happy new year ...
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BYoesle
Post Laureate
Reged: 06/12/04
Posts: 3510
Loc: Washington USA
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Thank you very much Jim -- your explanations and photo's are fantastic.
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Bob diagonally parked in a parallel universe...
Your heart is free. Have the courage to follow it.
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JimK
professor emeritus
Reged: 09/18/05
Posts: 635
Loc: Albuquerque, NM USA
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The O-ring is just a small, non-destructive addition to reduce or limit the rotation of the diopter/finder focus adjustment. I used an o-ring thickness that corresponded to the focus point, thus the focus is now semi-fixed and I do not have to worry about readjusting it after unintended contact.
O-rings are also useful a parfocal rings, that is, spacers to make different eyepieces roughly parfocal and thus requiring only minor focus adjustments when switching eyepieces. I also use o-rings as a cushion between two metal mating surfaces to help prevent unintended unthreading or metal-to-metal binding or "clanking" (i.e., thus resulting in soft landings).
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JimK
professor emeritus
Reged: 09/18/05
Posts: 635
Loc: Albuquerque, NM USA
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GR1973
I have the same small indent above the setscrew on my declination lock, but not on the declination adjustment knob. It's very small and I never noticed it before. I'm not worried about it, for it is almost invisible in the reflection of the setscrew area itself.
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GR1973
super member
Reged: 09/29/07
Posts: 121
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Very thanks Jim.....I mean that these small indents on the declination lock of my scope (the same as your scope)so,it's normal to be found in a new scope... 
I want my new Questar to remain in a mint condition
About O-ring 
very good idea to protect the focuser and make it more stable....do know from where can i get and which diameter is suitable to use
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JimK
professor emeritus
Reged: 09/18/05
Posts: 635
Loc: Albuquerque, NM USA
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GR1973
I obtained my o-ring from a place that sells plumbing supplies. I no longer remember the exact o-ring size that I bought - if it breaks I'll just take the pieces to a store and buy another that looks about the same size.
My eyepiece holder has an outer diameter of 1.289 inches (32.74 mm). An o-ring that fits snugly should work. Its thickness will depend on the eyepieces used and finder focus distance. For some maybe a couple of o-rings are needed, for others maybe no size would work. It all depends.
OPINION - I believe that my Questar telescope is to be used, which means that it will never be mint, nor perfect, nor free of scratches, nicks, and dust. When I first received it new it wasn't in mint condition. When I received it after factory maintenance it had more scratches and nicks (and even a dent that was subsequently fixed). But the telescope works and it generally looks nice. I do not think these telescopes should remain in mint condition - they need to be used.
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unkastro
super member
Reged: 12/09/07
Posts: 103
Loc: Sugar Land, Tx
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As a Questar worshipper, but not, and probably never-will-be-an-owner, I think a disclaimer *spoiler* alert warning should have been posted at the start of this thread. Somehow I had thought, fantasized, just knew that the inside of the Questar would be filled with magical jewels, Swiss chromed sprockets and gears, and unknown mysterious shiny objects that made this marvelous telescope work.
I am now horribly dissillusioned........cork(?!), flathead screws(?!!). I am crestfallen. 
.....
Okay, I'm better now. 
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UnkAstro
Celestron 6 SE
24mm Televue Panoptic
8mm and 6mm BOTMB Planetaries
Celestron Deluxe Shorty Barlow
6" Seymour Solar Filter
Astro-Tech diagonal
10 x 50 Celestron binocs
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cbwerner
scholastic sledgehammer
Reged: 08/27/05
Posts: 846
Loc: Maidens, VA
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Chris Werner
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otan
journeyman
Reged: 03/26/08
Posts: 7
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Appreciate the detailed photos and posts. Off to the hardware store for some O rings.
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