Hi guys!

The Z-Axis on my MV Junior has started to make a humming noise, when it is near zero return or at zero return.

The noise starts suddenly and sometimes disappears from itself.

I made this video to record it:


It clearly comes from the Z servo.

As soon as I move the axis a little bit away from the zero return position, the noise disappears, as shown in the video. In the video I then return to home, and the noise does not re-apear. Only to come back some minutes later.

I really dont know where to check for a problem. Its like the servo is oscillating at this position, but why should it?


The Z-Axis on this machine does also have two other strange issues, but which do no trouble me much, but maybe are connected:

1. Often when I turn the machine on and want to home all axis, I get a z-axis soft limit error, when the axis is homing. Only way arround it is to restart the machine in IPL mode, disable soft limits, home, then restart und home again, and it usually does home without a problem then.
2. I cannot run the z-axis with 100% rapid speed toward the Z+ direction (towards zero return position). When I do this, the axis abruptly stops (after approx 1 second) and the machine throws a alarm (Z AXIS EXCESS ERROR (MOVE)). It only alarms with 100% rapid. If I go with 50% rapid, everything works fine.


When I move the axis by hand (by turning the powered off servo, it moves freely to my opinion. I cannot feel more resitance or a problem near the home position.


Has anyone and idea, what this could be? Or what to check?

Thanks for any advice.

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