No PWM Outputs with Custom Breakout Board for Pixhawk Cube


I am creating my own custom carrier board for the Pixhawk cube. I am running into a problem. I flashed PX4 firmware to the Cube and installed on the custom carrier board. I plug everything in and start up the flight controller. I cannot get the ESCs to initialize. I checked the PWM output on the scope and I get a 1500 us PWM signal @ 50 Hz.

When I plug in to default Pixhawk Cube carrier board (made by ProfiCNC), the ESCs initialize. I check the PWM outputs on a scope and I see 900-1000us PWM signal @ 400 Hz, which is what I would expect.

With exception to the carrier boards, the two systems are equal. On my carrier board, I am not using the power selection PCB. Other than the PWM outputs, I do not see any errors in QGroundControl and the other outputs and status indicators appear to be identical.

Any help would be much appreciated. Thanks!