I hadn't planned to do it, but I just finished up some mods to an R2-D2 figure. The retracting sensor mast has been replaced with a new scratchbuilt one, that is not connected to any automatic mechanism. I hate it when I can't just turn the head on my astromechs, without something happening. I also wound up repainting all the white on the torso, after having to patch up damage from trying to modify a glued on panel. There was just too much difference between my paint, and the plastic.
I gutted the original mechanism, that made the factory sensory mast pop up, when the head was turned. That pretty well restricted the head to mast down/looking right straight ahead, or mast up/head turned 90º. The sensor head didn't even look like the movie prop. The new sensor head is just thick styrene, sanded and filed to shape, with a piece of thin sheet on top. The mast is clear acrylic dowel. I spread some super glue around the acrylic at the bottom, and near the top, to create friction to hold the sensor in place fully extended, and fully retracted. It rides in a short piece of plastic tube mounted in the dome. It can turn 360º. I made a small button on the bottom of the body that pushes the mast up just enough that I can hook a fingernail under the top of it, without trashing the paint. It only works if the head is facing relatively close to straight ahead. Nothing blocks head movement, with the sensor up or down.
He's a sneaky little droid.
