One of the draw backs of an all in one unit like this is when problems occur you are left floundering a little

Problem
Midi Light stays on and patch 001 is selected no matter what I press on my Ground Control Pro. Can change patch via Axe Fx ok

Configuration

Ground Control power supply is connected to the Axe Fx phantom power socket, the Ground Control is powered via the Axe Fx by a 7 pin Midi cable

Trouble shooting

1- Unplug GCP - Light goes out. - Plug back in Light comes back on

2- Disconnect every cable incl all power cables and plug in again- Light comes back on

3 - Wipe memory on GCP - No change

5 - Try a 5 pin Midi cable and power GCP directly - All OK

6 - Try 7 pin Midi Cable and power GCP directly - All OK

Conclusion

Power pin on either, cable or one of the sockets is shorting to a Midi signal pin.

I shall meter them out tonight and hope it's the cable and not a socket problem or something worse.



Does my logic make sense to anyone else, have I missed any other step?

Did you browse through Here?
Most the solutions people look for regarding the axe fx is here. It's one of my favourite pages on the internet

I've been on the forum and emailed both Fractal and G66.

I came to my conclusion before I recieved an email back from both so updated both with what I found.

I really hope it's just the midi cable,

I had the same problem midi cable was bad I got a new one and it fixed the problem!
I hope there is nothing major!

I metered the cable and one of the power pins was shorted to a signal pin.

Great! I am glad you figured it out!!!! I had the same problem and got the same solution!