Navaid Devices AP-1, Руководство пользователя

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At the edge of the dead zone, the servo electronics switch the motor on, but only
about 25 of the time. A series of pulses overcomes the internal friction of the servo
and exerts a modest amount of torque. The airplane has to drift out to 2.5 miles
before the ON time of the pulse becomes 90 and the torque is at almost a max. value.
The easiest way to overcome the problems referred to above is to increase the GPS or
LORAN sensitivity. If you can set the sensitivity to 0.25 mile per dot, instead of the
standard 1 mile per dot, the above numbers do not look so bad. Check to see if this is
possible with your receiver-unfortunately not all were designed with autopilots in
mind.
D) Verify that the autopilot is working, i.e., return the autopilot to Navaid for a bench
check.
If you have a proven signal and still cannot get it to track, and you cannot think of
anything that would put a load on the system (e.g., friction, heavy ailerons, or a
heavy spring in the trim system), check with us. We will probably ask that the
autopilot be returned for checkout.
If we find that the autopilot is functioning, there probably is more friction than you
realize and you really need to do whatever it takes to free up the system. But
eliminating friction can be a most formidable job, and we will talk it over with you
and try to come up with a less drastic alternative.
One such alternative, that can be used in the case of a GPS or LORAN that does not
have user settable sensitivity, is to change a resistor value inside the AP-1. We hope
to find a resistor value that increases the AP-1 gain enough to make it work off of the
GPS or LORAN signal, but unfortunately this will probably destroy the machine's
ability to track the VOR.
This trick is new with us, and we do not know the proper resistor value. But we can
send you a potentiometer that you can temporarily wire in place of a resistor.
Hopefully you can dial in the appropriate resistance while flying, then solder a fixed
resistor onto the printed circuit board that has about the same value.