If you press and release the left red button do you get a 6 on the display? If you do press and release it again and quickly press the right red button before the 6 dissapears. This might reset the system. Don't know what the 9 represents.
If you get no response from the reset try this. Pull and reseat the hopper 4 or 5 times. Reseat all connectors on the i/o board a few times. Reseat the ribbon cable on both ends from the i/o to the mpu. Check all pins in this ribbon cable as well.
Maybe this will help get you to square 1. Good luck!!?