[Antennas] my beam moves itself!

[Gary Morgan]

i have a problem with my CDE Ham II rotator (purchased used about three 
years ago). it goes like this:

a couple of weeks ago, i noticed that my beam seemed to be moving itself. i 
figured i could check whether the control box was at fault by simply 
unplugging the unit from the electrical outlet.

so the next day, i plugged in the unit, pointed the beam due north for a 
sked, then turned off the control box and unplugged it.

a few hours later, i went outside and looked and the beam had turned itself 
180 degrees and now pointed due south. i repeated this experiment just in 
case i had had something wrong the first time. but, indeed, without power, 
the beam moves itself to due south.

i doubt that the clamps are loose: when i move it back to north, movement is 
same as always and it's not a problem.

i'd be grateful for ideas from anyone about what to do (i know, i know...get 
a new one and use this to anchor a boat somewhere...)...if there's 
reasonable fix, i'd prefer that.

thanks much,
73s,
gary
kd0al