RCU Forums - servo problem

Hi
Hi for my master thesis aviation engineering at VUB. I have to make a test bench for scaled blades of a helicopter.
I'm using a GT5.1 Gyro and 3 Futaba s3003 servo's for the rotor. With my previous test bench the FBL system worked perfect. Now i made some adjustments and the servo's are acting weird. When i give full throttle, one of the servo's give short pulls on the swashplate without any reason (i don't touch the transmitter except for the throttle). I know this is probably because I have mounted the heli to a test bench, but i find it weird that the heli didn't do this before. Anyone an idea what I could do to stop this?

kind regards

Cathal