I started over and completely rebuilt the XY register. I was having trouble with the bus drivers. I switched to 74HC245's from 74ACT241N's. The 241's were actually dual 4 bit buffers each with their own enable line (one active hi and one active lo). The enable lines couldn't be tied together and each 4 bits was output on opposite sides of the chip which made wiring really messy. I also got new wire delivered which is the same guage (22AWG) but has a thinner insulator and is much nicer to work with. I've tested out all the functions and they all work: X inc and dec; Y inc and dec; XY inc and dec; load XY from address bus; load X or Y from data bus; push X or Y to databus; push XY to address bus; and reset. Only thing left is some control signal logic which I am missing some OR gates to complete. I neglected to order them earlier. I think I'll build the ALU next.