[TowerTalk] Orion Rotator Problems

[jcowens1 at comcast.net]

I would recommend calling Mike (Owner) of Msquare and discuss this with him. He is very nice and very helpful. He is naturally very busy, but will return your call. If it were me, I would get the controller out of the equation to start with. Try driving it with a separate power supply. They made AC and DC versions so you will need to know the voltage type and level. I used a variac to drive mine when I had controller problems and it worked fine. They have limit switches so you can't drive it beyond limits. That will tell you if you have controller problems or not. 

John Owens - N7TK

Message: 3
Date: Fri, 26 Oct 2007 18:58:36 -0700 (PDT)
From: Steve Jackson <kz1x at yahoo.com>
Subject: [TowerTalk] Orion rotator ... trouble?
To: towertalk at contesting.com
Message-ID: <778478.23697.qm at web34601.mail.mud.yahoo.com>
Content-Type: text/plain; charset=us-ascii

I have the M2 Orion rotator (sorry, 'positioner') with the RC-2800P-A controller 
unit, red LED vintage.

It's sitting in the tower on a shelf near the top of 80' of 55G.  Turns an 
Optibeam 16-3, a rotating 40/30 M2 dipole, and a F12 N1217 dualband WARC yagi.

Has been there for about 7 years with no troubles until today.

I find that I can't turn the antennas counterclockwise ... I try to dial in a 
heading of, say, 160 degrees when I am at an indicated 197 degrees.  The display 
(in mode 1 at speed 1) shows that it 'wants' to go there, the relay clicks, but, 
nothing.

The other way is bad, too:  An attempt to go from 197 degrees clockwise to, say, 
220 degrees DOES increment the reading - very slowly and erratically - and only 
by a few degrees.  Then it stops.  Can't go back CCW afterwards, either.

Attempts at control via the serial port result in the same actions.  The control 
box is not overheating, or acting oddly in any way.

DC voltage on the disconnected motor line shows about 48V DC at the box 
terminals.  The disconnected control line voltage is 11.6V at the box.  A 
resistance check of the motor leads (at the box end, and disconnected) shows 
megohms, but inexplicably with a 'negative' sign when the test leads (Fluke 177) 
are reversed... odd, like it was being powered from someplace ... and there are 
about 300 mV on the motor wires.  That might be a clue.  I haven't the foggiest 
idea how one can get DC voltage off of 400' of a pair of wires that terminate 
into a motor winding!

A quick walk out to the tower, 300' back in the woods in the misty rain and at 
night, shows no obvious anomalies.  Of course, I'll do a more thorough check in 
the morning when it's light out.

Ideas?