No, I am running Windows 10 on a PC.

The screen size is 15" wide x 1 high and the resolution is set to 1280 x 1024 (the highest).

Plugged in the wide-screen monitor which allowed me to see half of the Xbox icon, a slight improvement but still not full screen. This allowed me to at least activate the Xbox controller. I then plugged the cables back into the other monitor and could see the same screen, but it was distorted. I rebooted the PC and the original screen appeared, but no Xbox icon . I'm not quite sure what the issue is, but it's as if Windows remembered the settings from the wide-screen monitor which was then output to my normal monitor when plugged back in.

Yes, the display setting is set to 100% and I have tried other settings without success. The next thing I can try is to use a widescreen monitor to see if that makes a difference.

Looking at the confusion in the manual, I decided to do a few mods. The 5V PSU will only power the limit switches and the encoders. I then decided to power the teensy, relay board and the mega from buck converters to get the correct voltage to each which means that they will be permanently powered, but then cut the red wire in the USB cables so they are not powered from the USB. Unfortunately, I have still got to complete the AR3 build, but I have wired it up outside of the control box and it seems to work okay. We will see what happens when it is finally put ino action.

The limit switch on J1 is a little tight and sort of untidy. I opted to fit the pre-wired version of the limit switch and in fact changed all of the switches to pre-wired (much neater). The only limit switch that didn't actuate properly was on J4, which only required drilling and tapping new mounting holes.