Thanks for such a quick reply. I have reset the power several times and reseated the connectors on the controller board with no luck.
Regarding the power in and out of the boards: The connection from the power board unit to the display board unit is from P9 on Power to P1 on display board unit. Are you thinking the low voltage power comes in on pin 1 of P1 on the display board unit? Also, any guess as to what the low voltage is? Looks like 24VDC is generated on the power board to throw a relay elsewhere. Is it possible the Display unit should use 24VDC?