Spent some time today wiring up a circuit to convert the lower 5 volt logic 1's to 12 volts. I am using just a basic non-inverting buffer using two not gates for each input of the ALU. So far I have one board that takes care of the A inputs. Next I will wire up the same board again for the B inputs. The photos below show the ALU and the newer level converter board. I will be adding some leds as power indicators.