TruTrak problem

I finished installing a used TruTrak ADI pilot II and during the ground checkout observed that while the roll servo does fire, it doesn't have enough torque to move the controls. Pitch servo works fine. I've verified that the shear pin is good.

My issue seems to be that I'm only getting 4 volts at the servo. Also verified that I'm only getting 4 volts output to the servo at the control head. Checked all the grounds and no issues there. Could there be an issue with the control head not sending enough power to the servo? I reworked the connector as well hoping maybe a pin wasn't seated correctly but no luck. What other places could the power issue be traced to?

Have you checked the lateral torque setting ? The install manual explains how.

Gary

gmkonrad said:

Have you checked the lateral torque setting ? The install manual explains how.

Gary

Click to expand...

Yes, all settings were done per the instructions in the manual with the lateral torque set to 12.

Cole,

Maybe you already tried this. Have you swapped servos to see it the problem follows the servo, or stays with the roll autopilot? Kind of a PITB, given it means pulling the pitch servo out of the aft fuselage to try it in the roll position. Don't forget to complete the test and run the roll servo in the pitch servo position. It would give you the answer: servo problem or A/P problem.

Steve, I haven't tried that yet but sounds like a good process of elimination. Trying to get assistance from Andrew Barker but that process is turning out to be rather time-intensive.

You could try contacting MidContinent Instruments, as they are now the warranty and service provider for TruTrak now that it is part of Bendix King.
https://www.mcico.com/

M5fly said:

Yes, all settings were done per the instructions in the manual with the lateral torque set to 12.

Click to expand...

Following up on this, and easy thing to do would be to change the torque value up and down just to see if you get different results.

Sorry I wasn’t more helpful yesterday - I had just gotten off a plane from Africa and I’m trying to get my time zone legs back under me!

Paul

Apologies for the delay, as I am traveling.

Anyway, the servo swap is a great idea to see if it follows the servo, as is calling MidContinent for help. Also, varying the voltage to verify that it moves up and down. This will verify that it's moving correctly, but also that it is wired correctly.

While I am happy to give support, my resources are limited to my knowledge of the products and the manuals. MidContinent is the primary service and support center for legacy and current products.

Thanks!

Following up... I changed the torque setting and voltage changed along with it, so that rules out incorrect wiring. Checked the voltage at the pitch servo and it's also receiving 4 volts so that doesn't seem to be the problem either. Swapped servos and same result. The issue does not follow the servo and remains with the roll function. I've been doing the ground tests stationary right outside the hangar, could it be as simple as the roll servo not working properly until I get to a minimum speed? I've heard a mention of 20kts before the nav function will work.

Final follow up for anyone who might run into the same issue. Tried another control head and everything worked flawlessly on the ground as it should. Haven't had a chance to test fly it yet but am not expecting any issues. So if you get into a similar situation and eliminate all other issues, the control head may very well be your problem.