Autopilot Servo

[Paul Sharp]

Cool stuff. I really appreciate the details. I'll try pulling out the electronics guts and see if I can find someone to check the transistors. I'm a ham and have elementary knowledge but never did much building and never tested transistors.

My potentiometer in the Control head sets the heading. But it obviously follows the DG because if I move it with the precession knob it changes the heading the A/P is taking accordingly. And I was in error in referring to a "heading bug" as my DG doesn't actually have one. It has simply the adjusting knob for precession. So it would seem that my outer adjusting lever in the middle of the A/P just allows things to be centered for balance/fuel, etc.?

Also, if there's something in the tail I wasn't aware of that - mine is only a one-axis A/P and I don't have electric trim. So I don't believe I'd have anything in the tail unless there is something on the rudder (seems unlikely), would I?

The guy at A/P Central in Tulsa said it was probably either the servo (as you've been saying) or it could possibly be the turn/bank indicator which might have lost it's sending to the control head; that apparently makes sense from a standpoint that it helps keep the plane straight-and-level?

The potentiomenter - it seems that if it's nothing other than a pot that it would be unlikely to fail, wouldn't it? I would more suspect the transistors, from what you've said, shouldn't I?

When you said clean motor brushes, etc. - does that mean they're accessible once the electronic half is out?

If I need a transistor all I have to do is replace with same model number, I assume? I mean mine is a 24V system although it may be stepped down to 12V for the A/P it sounds like not so, but if you replace a transistor with the same model number the voltage will be right, won't it?