AP74 No recognition


New Member
Nov 30, 2019
Greetings from Melbourne, Australia,

I have recently completed the mechanical installation of an AP74 and both Roll and Pitch Servo's in my RV7A and whilst following all supplied installation instructions, have had no problems whatsoever.

On completion of the above, I have updated both my EFIS D100 and EMS D120 to the most current Firmware version and noticed whilst doing so, that the AP74 wasn't being recognized. It recognizes EFIS D100, EDC-D10A and both Servos - but no AP74. I did nevertheless progress the configuration and completed the Servo calibration and intial setup successfully, so it would seem that the connection between the EFIS and Servo's is correct. Both Servo's can be operated from the EFIS.

All buttons on the AP74 are illuminated with Red which I understand indicates that there is no communication with the EFIS. I have double checked all four wiring connections (Black, Red, Blue, Green) as I am not utilising any form of audible alarm. All connections appear to be correct and as I have illumination on AP74, there seems no doubt about power being supplied and correct.

I have repeated the DSAB configuration process and it still does not recognize or 'see' the AP74 whatsoever.

Your assistance and suggestions would be greatly appreciated.
Thank you in anticipation.