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Disassembling the Transmitter

All the electronics must be removed from the transmitter except for the trainer switch if one is installed. The antenna, battery, trainer jack, main circuit board, etc. are not required and should be removed to reduce the chance of shorting +5 V and ground. The wires for the four gimbals' pots are cut from the small circuit boards to which they are attached. The two gimbal assemblies are removed by removing the four screws holding each one in place. The gimbals are different and must go back in the same location from which they were taken. If the new pots are more than 3/4" diameter, the meter and power switch must be removed to provide the necessary clearance. The components that are removed can be saved as spare parts for another transmitter.

The pots in the radio must be replaced to increase the resistance range to match the average joystick. Only one pot assembly should be disassembled at a time so that the other can be used for comparison. Start with the throttle stick - first remove the thin spring steel strip that provides the friction for the throttle stick is removed. The pots are attached to the assembly by a brass bushing but are free to turn within it to allow the pot to rotate slightly in either direction for trim adjustment. The two oblong cams attach the pot to the trim tab. The screws that hold the side of the gimbal in place are removed and the side will come free with the pot and the trim cams attached. The pot's shaft is attached to the gimbal assembly with a snug fit. It can be removed by prying gently with a small screwdriver if necessary. There is another cam on the inside connected to a spring and a tension adjustment screw. This cam allows the stick to spring back to center. The tension screw is loosened first to avoid losing the spring when it is removed. The spring, cam, and tension screw/block are removed. To remove the pot, pliers are used to carefully loosen the brass bushing from the inside face of the assembly. Care must be taken to avoid damage to the bushing. When it is loose, it can be unscrewed by hand. The pot will come off along with the two oblong cams.


next up previous
Next: Modifying the New Pots Up: Build Your Own Flight Previous: What's Required

Craig Kulesa
Thu Nov 4 17:28:36 MST 1999