AP74 buttons inop

[slipstream]

I just bought a used AP74, and installed it into my system, alongside a D100, HS34, and EMS-D10. Everything checks out but the buttons and value knob on the face of the AP74. The lights work, so if I’m in heading mode, those lights are active as they should be. Controlling the autopilot requires the D100 AP menu and/or HS34. Is there a setting I‘m missing?

 

[Dynon]

No. If the mode lights are working (and not all permanently lit up, which indicates a problem), the buttons should work too. There isn't a setting to disable/enable them.