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LXD 75 RA problem

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#1 Orion4211

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Posted 25 April 2009 - 03:54 PM

Ok so I bought another counter weight for my LXD 75. I have an 8" SCT which I wanted to mount with my 80mm Refractor. When I put both weights on, I noticed that in the RA slew, the gears were not lining up together. The whole RA housing pulled back a little bit. (if this makes sense) With one scope and one weight I am not having a problem... But I am with both. Anyone know why this is happening? And if so, how to fix it. The housing for the RA does wiggle a little bit if I move it. Any ideas on how to tighten it so this doesnt happen?

#2 jgraham

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Posted 25 April 2009 - 05:08 PM

Wow, it sounds like the whole RA motor assembly might be loose. This assembly is held in place by a single hex key (Allen) bolt that's located on the under side of the polar assembly just below the polar scope. If you reach up inside with an Allen wrench (I forget what size, 5mm?) you should be able to tighten the bolt. When I adjust mine I keep an eye on the drive gearsto make sure they're closely aligned as I tighten the mounting bolt.

#3 Orion4211

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Posted 25 April 2009 - 05:11 PM

Ahh. I see. I have had the mount for about 4 years now and I have never adjusted a bolt or anything. Maybe its time...

The mount should be able to handle two of the 10lb counter weights right?

#4 Orion4211

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Posted 25 April 2009 - 05:17 PM

OK i just looked at that bolt and it was loose. I tightened it up. I guess 4 years if use caused it to get loose a little :)

#5 FoxTrot

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Posted 26 April 2009 - 01:51 AM

Ahh. I see. I have had the mount for about 4 years now and I have never adjusted a bolt or anything. Maybe its time...

The mount should be able to handle two of the 10lb counter weights right?


4 years of use and no need to tighten anything, consider yourself very fortunate! Other things to watch would be the silver and brass cog/gears of the motors and worms, they can de-couple and become slack if the locking screws work loose over time. You will need to take off the motors and open the plastic 'shells' to tighten if needed. You can inspect if there is any cog slipping via the little side windows, and then play around with the RA/Dec controls on the HC box.

#6 Orion4211

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Posted 26 April 2009 - 08:29 AM

OK. I have checked out the slipping and I have not found any slack. I was thinking recently about greasing everything with new grease, but maybe I should just leave it alone.

#7 jgraham

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Posted 27 April 2009 - 09:58 PM

Nahhh, that's actually a good idea. I usually take both the dec and RA assemblies off about once a year to clean and re-grease everything. It's also a good time to check the alignment of the polar scope and re-train the drives. There used to be a PDF file on OPT's web site that had tune-up tips for the LXD75. There might be something similar on LXD75.com.

#8 Orion4211

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Posted 28 April 2009 - 10:07 AM

oh thanks, I will check out OPT for that.






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