Yeasu G-5500 DC - Jumpy azimuth encoder reading

I’ve been using the Yeasu G-5500 DC rotator for about a year now.

In the last few weeks, it has started to develop an issue with the azimuth encoder reading. The azimuth needle on the controller was jumpy when the azimuth motor was moving, even the physical movement itself was smooth. I’ve measured the voltage coming from the rotator and the voltage was jumpy as well.

This causes a problem when moving the rotator to a position. For example, when I’m trying to move the azimuth to 180 deg, the rotator would stop before it reached 180 deg physically since the voltage input from the rotator was slightly higher momentarily (showing 180 deg before reaching 180 deg).

I’ve put a video on Youtube to show how the needle reading on the controller moves. The movement on the rotator itself was smooth but the encoder voltage reading was not.

Do you know if this can be fixed? The elevation motor was fine, only the azimuth is having this problem.

I’ve used the older G-5500 AC model for a long time before this and never had this issue. I would appreciate any help from you to sort out this issue.

Oh dear, that looks a lot like a dirty or otherwise damaged azimuth position feedback potentiometer.
I guess everything has some lifetime, including those potentiometers. I suspect the only way to resolve this is to take the rotator down and replace the potentiometer.

It looks like Yaesu can provide replacement potentiometers, as mentioned here:

I’ll contact you via email separately and see if there’s any way we can help out via work too.

I think it was mentioned in the link Mark posted, that the azimuth is a G-800.
I have replaced one of these in a G-1000 and it is some work and a bunch of details to pay attention to.
Moisture and age kills the pots eventually, but the rest of the mechanism seems to be fine. Good to clean the bearings and re-grease it at the same time.