Newbie unable to arm

Hello Everyone,

I am making my first quadrotor (350mm) as a training quad. I also have all the parts for a 550mm FPV capable platform on order. For the trainer quad I wanted to be able to use mission planner because that is what I will be using with my PX4 when it arrives. Unfortunately I am having problems.

I am using a Crius AIOP V2 board with MPNG 3.0.1 and Mission Planner 1.3.7. I have uploaded a sketch to the board using all the defaults except that I had to change the receiver settings to regular PWM because I as not sure how to make my Turnigy 9x and 9x8ch v2 receiver do PPM sum. I have connected to the board via Mission Planner and successfully calibrated accelerometer, magnetometer and transmitter. I have changed the pre-arming check to disabled and written that setting to the board. Yet, when I hold my throttle down and to the right my quad stays disarmed. Currently I only have one motor plugged in (I just wanted to see which way it rotates).

Any ideas what could be going on?

Screenshot of my flight data screen

Screenshot of what my inputs look like when I am holding the throttle down and to the right.

can you arm from the ground control station, a button on the action tab?