Bob,

The "out voltage adjust" pots are used to calibrate the "external control" via the DIN jack going to the computer interface. The out voltage pots will not affect the meter. They will have a major impact on computer control if you use it.

As you stated, the "Full scale" pots calibrate the meter system.

The next likely cause would be something in the rotor cable shorting or grounding. Beyond that, there are too many possibilities for an email.

BOB KO6TZ

On 11/18/2016 02:21 PM, Robert Bruninga wrote:

...

When you say the voltage pots do not change anything, I suppose you mean adjusting them does not fix the problem.

No, I mean they do not affect either AZ or EL meter reading. Turn pot end-to-end and meters still correctly read the AZ and EL and an external voltmeter does not show any change on the We used the full scale pots to calibrate the system, since the volts adjust pots do nothing..

Further, when the 10% glitch happens, it stays down permanently even with the motors not turning and no fingers on the switches... until it glitches back up eventually..

Thanks Bob

-----Original Message----- From: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] On Behalf Of KO6TZ Bob Sent: Friday, November 18, 2016 5:01 PM To:amsat-bb@amsat.org Subject: Re: [amsat-bb] G5500 AZ/EL controller Glitching?

Bob,

My guess is that since it is only when turning Left, the problem is with the "bow-tie" or something mechanical in the break that is causing a lot of drag on the motor when turning left. Try measuring the voltage between lug 6 & 4 turning left and compare to the voltage between 6 and 5 turning right. I suspect the load or drag is drawing down the secondary side of the AC transformer, affecting both the feed back circuits and the drive motor.

Easier said than done, since as you state the issue is intermittent and the switching action clears the problem.

When you say the voltage pots do not change anything, I suppose you mean adjusting them does not fix the problem. That is, it is not a dirty pot issue.

BOB KO6TZ

Apparently the internal 6v supply is dropping since both meters glitch down and an externmal voltmeter on the rotator feedback terminals also show the same10% drop in the 6v line. (though it appears to be a constant 5.5 volts not 6) And then glitches down from the 5.5.

Also noticed the Adjust voltage pots on the back do not change anything.

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