Question about STEC 30 autopilot

[AndreiC]

I recently pulled out my perfectly functioning STEC 30 autopilot head from the panel (to gain access to the DG) and when I put it back in it failed to start up. When I checked the connector, it turns out I had bent two pins. However, even after straightening out the two pins and making sure they now go in correctly, still the A/P does not start up. What it does is that the gyro is spinning up as it should, and when I flick on the A/P switch I can hear the servo in the back go through the motions, but I get no lights on the autopilot face to light up.

One other thing -- when I opened up the connector to inspect it, there is one loose black wire that I suspect is a ground that appears to have been disconnected. But I don't know if this has been like this for a long time, or it is from me messing around with it.

A local avionics shop offered me to put together a small harness with just two powers and two grounds (for the A/P and for the gyro, which are independent) and see if it lights up on their bench. 

My question -- do you guys know if these autopilots show any signs of life (like lights coming on) before they go through their self-test? Would the test proposed by the avionics guys show me anything, or is it the case that if the system does not power up on their bench it means nothing (like, it went through self test and did not find responsive servos, etc. so it shows nothing?)

Another question -- I attach here the interconnect diagram I have found for the STEC 30 autopilot. Can you guys tell which one is the autopilot ground connection? Is it the main one on pin 34, or is that just a safety grounding pin and there is something else going on? If I were to take a wild guess, I'd assume that the autopilot head is not getting power (but the pitch computer is, hence I can hear the trim servo being initialized), and the most natural guess would be that the ground line (the black line I found in the connector) is disconnected. But when I checked the connector, there definitely is a black wire going to pin 34.

Thanks.

[AndreiC]

Forgot to attach the interconnect diagram.

[Rwsavory]

https://webairconsulting.com

[Baker Avionics]

Make sure the selector knob isn't loose as in the shaft of it and make certain it turn with some sort of click.  If not, then the u joint for that is stripped or cracked.  It is a common issue with this system.  If you need one, they are about $80-100 and we generally keep 3-5 in stock for this reason. 

If you need help, let me know.  Love to help any way we can!!!!