So, I'm working on a clock design, and while testing the base counter after adding the buttons/MUX/DMUX, I came accross an issue that I can't figure out. The 4 input AND gate I'm using gives me an output with the voltage "UNKNOWN" when it receives 4 HIGH inputs. I have an identical counter in a basic implemention of the clock, and that works just fine. So, is this an issue with Multisim or my design? I've included the multisim file, I put rectangles around the problem area and the nearly identical circuit that works just fine. Help would be very much appreciated, I've already had two other people take a look at my design and they didn't see any problem with my implementation, so I have absolutly no idea what's going on.
Help is very much appreciated! Thanks for taking a look.
