RV Repair: norcold n641, white violet, norcold n641

Question
n641, blew 5amp fuse. replaced but had no output voltage at optical harness between white/violet & white/red wires.(at optical bd plug end). I replaced pwr bd but still no output at optical control bd. Refer cools on AC with no display but not DC and still no display. I do have output voltage at the pwr bd on P1 but not sure which pins are what. Is there anything I am missing in the circuit that would prevent pwr at optical bd harness even though I do have output at the pwr bd?

Answer
Jeff, Well there is the chance that the wires have been broken between the 2 places. You said you replaced the power board. Check the power to that board (12 volt) to make sure that you have between 10.5 to 15.4 volts getting there. Make sure no other appliances are connected to the refers dc circuit. and that it is wired correctly. If the F-1 fuse is good measure the voltage to the harness that connects to the optical display at the white/violet and the white/red wires If voltage is present then replace the optical display if not and you have the voltage leaving the power control board on those 2 wires then there is a break in the wires and you will need to repair it. If not then you will need to replace the power board. That is the procedure to test that part of the system and the only way that I know how to make sure of what it is. Thanks, Bill