I may have found one of the reasons for the APU malfunction. In the "Controls/Instruments and Systems/Electrics" menu, key 42 on the Honeycomb Bravo was assigned to the "APU Starter" command. I removed it, and it works.
MSFS2024 Inibuilds Tristar: The APU on this aircraft doesn't work when Honeycomb Bravo is connected. I disconnect it and it works.
I connect it with a Saitek X56 controller and the APU works. What could be the incompatibility?