27 replies to this topic

[apfever]

Yours is like the schematic in entry #8?

 

Take the thumbscrew all the way off. Check that the plunger length is long enough to engage the taper in the shaft. This is to confirm there is not a loose pin in there that the thumbscrew pushes on.  That collar should just come off. You could use the hole for the thumbscrew as a place to inject some penetrating oil. 

 

The thumbscrew might be made of soft metal. See if you can find a hard bolt with the same threads. Screw the bolt in the collar as far as you can without engaging the shaft. Then use the bolt as a lever to wiggle the collar loose. 

[PaulEK]

Thanks for  the suggestion. I do remember having a clone of this mount*** that someone had installed motors on. They looked like these, but had adapters to get the drive to work with some difference between the Vixen motors (IIRC they were Vixen motors) and the dimensions of the clone. I thought there might be something more than what the drawing shows in post #8.

 

Turns out that, nope, it's just the same. My issue was some kind of bug. And I mean the insect kind, not a glitch. I checked the RA drive first. It had crawled inside the motor housing and wedged itself up into the space behind the gears. It had dried up in there and mummified into something unidentifiable, yet definitely of the buggy kind. Either it excreted something while it was alive, or its decay let something out. Whatever it was, it acted like a very effective glue. I got the gear off by tapping it from behind, holding a small screwdriver to get at the gear, and a small hammer for force. Then I loosened the set screw that the gear had been covering, and removed the whole clutch assembly.

 

Once I got it off, I sprayed it with some de-greaser I had just bought for another project. It took some doing, and some water, too, but it cleaned up eventually.

 

The Dec motor had also been frozen (maybe I'll find another critter), but it came apart pretty easily once I opened up the housing. I'll clean it up once I post this.

 

***That clone was a 'deal' that I got in the late 1990s, and, boy, was it a mess. I did all sorts of 'hyper-tuning' to try to get it to work well, but the build quality just wasn't there. No matter what I tried, things were either too loose and bouncy, or they made a grinding that I could feel in my fingers, hear, and see in the results at the eyepiece. I found this Vixen mount while I still had the clone, and once I used the Vixen, I sold the clone as soon as I could, not asking much, and making it clear to the buyer that it 'worked', but just barely. The Super Polaris is a wonderful, smooth, well-made, adjustable mount.

Edited by PaulEK, 05 August 2022 - 02:12 PM.

[skysurfer]

I have this mount (the black one as shown in post #9) as well, since 1990 and still use it. Awesome. Now I have a 110 ED on it for both visual and astrophotography, in the latter case using my Canon EOS R6 DSLR. I have a Star Adventurer as well, but that is too light for the 110ED + DSLR as payload.

And I use it as travel mount as well with the 110 refractor. The SP (checked baggage) survived many baggage handling facilities (which means toss & throw) on several airports around the world.

 

A few years ago I bought another used SP for spare parts. The original MD-5 controller + RA motor which both still work is now powered by a convenient power bank with a voltage converter to 8 Volts as 5V is just too low voltage, so no hassle with AA batteries.