Autopilot Servo

[Bob Cook]

Paul

1) YES
2)yes, you can also put ohmeter right on the pot between centre on one side and centre and the other side. To check pot you do not need board plugged in or power on,.
3) see above
4) yes.. 10 volts not minus (-) 10 volts
5) check transistors for shorts with ohm meter. in or out of circuit. there should be a forward and backward value like a diode between collector emitter and base.
6) I will scan and send schematic but unable to do so until sunday. If you do the above I am sure you will narrow it down to one or the other.

if the voltage is missing (10v) then check the 10v zener diode (cr1). it can be replaced locally as well. This is the reference voltage for the pot and is dropped in the circuit from 24v to 10 volts. You should see the voltage on the wiper output as you move the ailerons with the autopilot on.

btw the 400 servos are different than the 300 as mentioned before.

regards

bob