wyager, thanks a lot for the advice. I am going to follow it!
the number of the beast ]By the way i see that you (wyager) use a lot of transistors for driving your project. Don't you have a 74141 off hand?ps. the optocouples i need, TLP627, are damn expensive
BTW, are the optocouples to protect the rest of the circuit from high voltage?
I had also failed to spot the utterly confusing layout of the logic pins on the IC. If you look you'll see that the pins are labelled A, D, B, C (in that order). The logic chart is labelled D, C, B, A.