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Vixen GP DX, decl clutch problem

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#1 Littlegreenman



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Posted 26 March 2009 - 03:10 AM

I just acquired a used Vixen Great Polaris DX and have two problems:

1. The dec clutch when loosened doesn't disengage from the motor; the motor is still engaged.

2. the dec axis is a little tight and uneven. Rotating by hand takes a little more oomph than it should. Rotating it through the range the resistance is uneven.

On the clutch: I don't exactly understand how the clutch is supposed to work. If I knew that, it would help me trouble shoot it. (To make it more confusing, I have a regular GP, and 3 versions of Vixen clutches around here!)

I can't see how the clutch and brass gear is mounted to the shaft. Is the the gear on the shaft supposed to slip when the clutch is loosened. Or the whole brass attatchment? I removed the motor and tried to remount it. No luck.

On the someone stiff axis. Is that likely to be an adjustment of the worm gear, of the friction surfaces deeper in?

Thanks for any clues, ideas thoughts.

I found Astronomy Boy's site, with a section on "Improving the CG-5 Mount. This is a tutorial with pictures and tips, that goes on for several pages. I assume this is similar to the GP mounts. If someone knows of any other links, that would be nice.


Astronomy Boy, Improving the CG-5 mount

..and I found this, there is a link on the left a little more than halfway down

Regreasing the GPDX

#2 rjsc2000


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Posted 26 March 2009 - 03:56 AM

The motor never moves from place. But if you loosen the clutch, when the motor rotates, the spur gear rotates but the scope doesn't...
Try also this site http://www.company7....ixen/notes.html

If the axis is not smooth, it may have to be cleaned and relubed. Not dificult but make sure you keep notes on the position of the washers.

The worm gear might be too tight. Try to loosen the screws and see if that helps.
When the clutch is disengaged you can rotate the axis by hand. Try that and if it feels stiff you need to relube. If not, it's the worm gear too tight.
You can also have a little bent worm gear. I think it's a little common. In that case only a new one will solve the problem, or you can try to repare it but it will never be 100% straight.

ricardo carvalho

#3 Littlegreenman



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Posted 01 April 2009 - 07:20 PM

I figured out the main the problem. The clutch gear was frozen to the clutch shaft. That is the gear in the middle of the picture; the motor and gear are to the right. The mount had reportedly not been used in several years. It took some elbow grease to loosed the gear, and now that problem is solved.

Adjusting the bolts over the worm gear housing have fixed the tight rotation and tight spot almost 100%. My guess is that a little more tweaking or regreasing will get the rest.

Thanks, Littlegreenman

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