[TowerTalk] Yaesu Rotor problem

[Magnus A]

Hi!

I have a Yaesu G-450XL rotor.

Last night somthing happend which may have been caused by RF feedback from another antenna (vertical on ground).
I was transmitting on my 80m vertikal when all of a sudden my rotor control box start to go nuts.
It was aimed south and all of a sudden the rotor controllbox dial starts to move clockwise towards north. When it reaches north I pressed down the left button and could make it move all the way down to south again but when I realased the button the controll box goes 3° left and right all the time from the center. It is moving like a ticking clock left right left right left right untill I power it off.
As soon as I power it on it starts doing the same again.
Now, when I went outside I noticed that the antennas was now almost beaming north, while controlbox was set to south plus/minus about 3° in movement.

What have happend? And how do I repair it?

Please help.

73 de Magnus SM6WET