[amsat-bb] Re: G5400 elevation issue

w4upd updwrb at bristor-assoc.com
Mon Feb 7 15:07:45 PST 2011

As I mentioned before, I do not believe it is the pot in the rotor. The 
meters on your control box read the rotor pot directly. Both the meters 
and the digital/computer portion read the pot directly. If the meters 
were erratic or wrong I would suspect the rotor potentiometer. There are 
4 alignment pots in the control box. One each for the meter calibration 
to track the rotor and one each for computer calibration. If you want to 
check the rotor pot, you can check the three lines that come down from 
the rotator directly from the pot and see what the the resistance is 
between three leads as you rotate the elevation rotor. Terminals 1,2 and 
3 are directly to the pot. E1 and E3 either side and E2 the center.


     Reid, W4UPD
     Amsat #17002

On 2/7/2011 5:51 PM, i8cvs wrote:
> ----- Original Message -----
> From: "Dave Webb KB1PVH"<kb1pvh at gmail.com>
> To: "AMSAT -BB"<amsat-bb at amsat.org>
> Sent: Monday, February 07, 2011 5:16 PM
> Subject: [amsat-bb] G5400 elevation issue
> The display on the control box reads correct elevation,  but on my digital
> display on the Easy Rotor Controller shows erratic elevation position. I
> have recalibrated it several times with no success. It won't read any
> elevation until it is around 20° give or take. It also seems to have become
> worse since our really cold temps set in. My best guess is the pot in the
> rotor, but not sure where to start in the process.
> Thanks in advance
> Dave - KB1PVH
> Hi Dave, KB1PVH
> If the display on the control box reads correct elevation then the 500 ohm
> pot into the rotor is OK
> By the way if the digital display on the Easy Rotor Controller shows erratic
> elevation probably the rear potentiometer VR4 in the rear of the control box
> of the G5400 is set erratic.
> Measure the DC voltage between pins 1 and 8 on the external control DIN
> connector. If the pot VR4 is set correctly the voltage must be 0 volt with
> elevation = 0° and 2.5 volt with elevation = 90° and 5 volt with elevation
> 180° i.e. with the antenna completely flipped to 180°
> The potentiometer VR4 is located in the rear of the control box as shown
> in the instruction manual.
> Have fun
> 73" de
> i8CVS Domenico
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