These people have Dinosaur boards which have a three year warranty and are superior to the Norcold boards. Check the part number that is printed on the actual circuit board to see if this is the board that this number will replace.
NEW Dinosaur PCB replaces Norcold 621267, 621269, 621270, 621271 : A.S.A.P.
Prior to replacing the board check the igniter wire from the control board to the burner. It sparks and lights the flame and also "senses"the flame by ionization to keep the propane valve open. If it doesn't sense the flame it turns off the gas valve. If you hear a snap snap snap and the flame lights but you continue to hear the snap snap snap at at about 5 second intervals then the flame shuts off the igniter and circuit board is not sensing the flame. Try changing the igniter wire and adjust to a gap of 1/8" to 3/16" first. They are only about $12.00 on the internet and if you end up having to change the circuit board the wire should be changed anyway.
My Norcold is a 8431M so I think the board is the same