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Losmandy GM200 Declination Axis disassembly

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#1 outthereguy

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Posted 19 April 2019 - 09:07 PM

Hi All, 

I have a dilemma. I use a GM200 as my main mount, tracking was more important to me than GOTO when it was purchased.

The issue I have is the grease in the dec housing above the encoder mount has stiffened up this last winter to the point of almost being seized.

I have searched hi and low for info on this and the only information I have been able to come up with has been here on CN and it was a photo spread on how to relube the RA axis.

That's easy peasy but the dec assembly has me stumped. I can get it down to the shaft, locking clamp. and bearing housing but I cannot see how to get to the bearings. On the bottom of the bearing housing, you can see a lock ring with two holes to engage a spanner wrench to loosen it. Figuring I had it made, I loosened it and to my dismay, it is larger in diameter than the hole in the top of the encoder housing. Now I have loose wobbly bearings that I still can't get to.I have attached two photos of the problem beast, I believe the part that has the spanner nut trapped (encoder housing) perhaps unscrews from the main bearing housing?? there is a seam that you can feel where the tapered housing meets the part that has the nut trapped. Any help is apppreciated. the and of the shaft is not splined, that is a 75T 80P gear cut into the end of the dec shaft for the encoder to run on.

Thanks

IMG_2283.jpeg [attachment=1249606:IMG_2284.jpeg

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#2 siriusandthepup

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Posted 19 April 2019 - 09:33 PM

Photo of bottom side?

 

I'm guessing that dec arm removes from the bottom and the bearing removal might be from that side...

 

Just a guess.



#3 outthereguy

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Posted 19 April 2019 - 09:43 PM

We thought so too, but after loosening the lock nut below the gear, the shaft feels like there is a pair of tapered roller bearings on the shaft, or at least one taper with a flat thrust bearing. And I don't know if the top of the shaft assy presses off, or unscrews? I would have put a pic of the other end on here, but I used my phone and the images were too big to allow 3.



#4 macdonjh

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Posted 20 April 2019 - 06:15 AM

A strap wrench to try to unscrew the encoder housing part that may be trapping the bearings?

 

On Monday morning, a call to Losmandy in Los Angeles might get all your questions answered.  They are usually helpful.


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#5 siriusandthepup

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Posted 20 April 2019 - 08:34 AM

 

On Monday morning, a call to Losmandy in Los Angeles might get all your questions answered.  They are usually helpful.

+1



#6 outthereguy

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Posted 20 April 2019 - 02:51 PM

Sent Losmandy an email last week. they're usually pretty fast at replying, but in this case, not yet.

There is a flat 1 ΒΌ inch thick 6" dia. aluminum disc looks to be pressed onto the end of the dec shaft opposite the gear. perhaps it comes off to expose bolts under it.

We tried an old leather strap wrench on it, Thats how I remove this assembly from the dec body to get to the encoder but even with some gentle heat from a hotplate, it won't turn. can't imagine that its LH thread, wouldn't make sense there. 




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