MGL Avionics User Forum

I just installed a V16 and Vega head as a standalone VHF com in my Pitts project and attempted to test it yesterday. Everything powers up, I hear myself in the headset and hear a slight tone change when I depress the PTT. The head, however, flashes a red warning message "COM Radio not detected." The green light on the V16 is flashing. Power and grounds are good. 120 ohm resistors on CAN bus wiring at V16 and Vega connectors. Vega setup as VHF COM. CAN bus wired per schematics. I can't find any information on the manual, online, or in any forums. Maybe someone here has some information on this.

-Jeremy

Have a closer look at your CAN bus wiring please - it's not connecting to the V16. The message goes away the moment it sees a data packet coming through from the V16 which happens around 8 time per second or so.

Use a ohm meter to measure across the CAN data lines. You should get 60 ohms (two 120 ohm resistors in parallel). Measure that with no power applied.
With power applied - measure the voltage on each CAN line with respect to ground - you should get around 2V and the readings will be slightly different on each line - if the same the lines are shorted. Measure this on each end of the cable, plugged into the devices. Ensure you get the same readings on each end.

Guess who crossed the twisted pair. This guy. Boy I feel dumb now.

Ha !
Don't think for a moment you're the only dumb guy around. Join the club. I'm a member too...

Trying to install the same system with the same problem. Every possible combination of the four 3-pin connectors gives me the "Com not detected" error message. Everything is tight and secure.

Aerco wrote: ↑Thu Jul 15, 2021 12:15 am Trying to install the same system with the same problem. Every possible combination of the four 3-pin connectors gives me the "Com not detected" error message. Everything is tight and secure.

Did you install the CAN terminator 3-pin connectors too?

I have two 3-pin connectors from the control head; one male, one female.
Also two from the radio; all male.

I tried every possible combination to connect these and none of them work. There is power at the radio.

Problem solved. It was the the two pigtails.