What you have is a known OR-2800 problem.
When that bolt on top of the shaft loosens, the shaft with the large
gear drops and causes the problems you have.
I have had this problem twice with mine.
I don't have measurements but I do have a few pictures of mine during
rebuilding which I will be happy to send you if you wish.
I fixed it finally by using some blue Loctite on the bolt the last time
I had to go up there and tighten it.
No problems since but stay tuned.
73 Les W2LK
On 5/30/2012 5:24 PM, Jay Kesterson K0GU wrote:
> On 5/30/2012 1:52 PM, K8RI wrote:
>> 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?
> No the rotor was inside the tower, had a thrust bearing at the top
> and there was very little mast above the tower. It rotated a H-Frame
> with four 7el 6m yagis (~20 sq ft) for 10 years. Not a huge amount of
> wind load but a fair amount of torque when the frequent CO winds blow.
>>> 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.
> There is a 1/4 inch bolt that screws into the top of the shaft.
> Perhaps all that is really wrong is the bolt unscrewed itself and the
> shaft/gear dropped. But I would like to verify the measurements just in
> case. However the more I think about it after your comments it's likely
> the only problem is the bolt worked loose because of the slop in the top
> plate. I bought a new top plate so I will just clean everything up and
> put it back together. Guess I just needed to think out loud with someone
> else. :-) At least I hope so.
> 73, Jay K0GU
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