Apparently youtube links aren't working anymore - anyhow - here's what I'm seeing. This is the first inverter off the clock signal. I sandwhiched an extra socket under the 7404 and bent out pin 6 so its connected to nothing, which eliminates anything else causing this to act up.
Pin 5 is the clock signal from the CPU. Pin 6 should be the inverse of it, but its not.
http://www.youtube.com/watch?v=j-pnDCs74a0
I've seen this now with 3 seperate 7404s I pulled from junk boards. I have a possible line on some new ones locally so maybe I'll try a brand new one tomorrow.