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Re: [TowerTalk] OR-2800DC questions

Subject: Re: [TowerTalk] OR-2800DC questions
From: K8RI <>
Date: Wed, 30 May 2012 16:52:21 -0400
List-post: <">>
On 5/30/2012 4:33 PM, Jay Kesterson K0GU wrote:

> Hi all,
>     Need some advice on an OR-2800DC that is about 12 years old. Over the
> years apparently the soft metal welded to the top plate, that attaches
> it to the hard steel output shaft, wallowed out creating a lot of play.
> This apparently caused the 1/4" guide bolt to unscrew and damaged the
> inside of the rotator. I replaced the top plate and that got rid of a
> lot of play. But I just opened to rotator to find a mess.

I'm not familiar with this specific rotator, but "in general" I'd be 
very concerned why the above happened.  Possibly there was an antenna 
mounted "on the rotator" rather than on a mast through a thrust bearing?
>     The big gear on the output shaft has lowered down somewhat into the
> rotator. The limit switch pin on the gear has dug into the torque plate:
What normally holds the large gear in the proper position.  I assume 
it's not the pin sticking out the bottom that operates the limit switch 
lever.  Due to the long drive gear it appears the position of the large 
gear is not important or precise, but it should not ride on other parts 
that are not designed to support it.
>     Also the gear itself has ground down the top of the limit switch lever:

This usually is not a precision fit, but I'd either remove the lever, 
clean it up and remove all the shavings before putting it back.  Or you 
could just purchase a new one, or have one made.

>     I believe the gear itself has slipped down the shaft about ~13 mm as
> the shaft looks very shinny for ~13 mm above the gear. If I measure from
> the bottom of the gear to the bottom of the shaft I get approximately 33 mm.
That takes me back to the question as to what normally holds the gear at 
the proper height?
   The gear teeth need to be smooth. I assume the surface of the gear 
should not contact the limit switch operating lever, nor should that pin 
ride on the metal plate, let alone with enough load to wear a grove in 
the plate.

I'd pick up some steel or brass shims to fit under the limit switch 
operating level to prevent the lever from riding on the steel plate.  
Shims can be purchased at most automotive stores for a nominal fee and 
they come in a wide range of thicknesses.
>     The part the shaft sits on rises approximately 7 mm above the torque
> plate:
>     I'm reasonably sure the problem lies with the gear position on the
> output shaft but wonder if anyone can confirm my measurements?? I sent
> M² an Email with all the above info but they suggested I sent it in for
> a $300 repair (plus $100 shipping) and made no comment about my
> measurements. So I would like to verify that it really is the gear on
> the shaft and fix it myself. Despite the look of the torque plate/limit
> switch lever everything seems to be working OK if the 7 mm measurement
> is correct.


> 73,  Jay  K0GU
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