The raster size potentiometers that are used in the 11-065 ion gun control are coarse single turn potentiometers that make it difficult to accurately reproduce raster sizes.
By replacing the single turn potentiometers with 10-turn 1% potentiometers, the accuracy of the raster sizes is greatly improved. This will improve the repeatability of your sputter rates when changing raster sizes. One turn of the raster size potentiometer will now equal 1 mm instead of 10 mm.
When you replace the 25 kΩ 1-turn deflection potentiometers in the 11-065 with 25 kΩ 10-turn potentiometers, note that CCW = black and CW = solid brown. The other wires are the wipers.
You will also need to replace the one turn raster size knobs with a 10 turn vernier dial.
TIP: When removing the old potentiometers you can simply cut the tabs off the old ones and then insert and solder the tabs into the new potentiometer. That is much easier than un-soldering the wires from the old potentiometers.
It is very important that the CW, CCW and wipers wires match up with the old potentiometers. Otherwise the raster sizes might be backwards (0 = full raster and 10 = zero raster.
If your 11-065 controller ever needs repair and you send it to RBD Instruments, we will ask you if you would like us to add this update to your 11-065 as part of the repair.