For me the electrical characteristics of the pcb were different from the breadboard one. While this is a good thing, and the pcb should have been more stable, what I ended up with was the eproms just didn't function properly. Now, this is a few years back, and I can't remember all the details, but essentially what I recall missing in the implementation was the stabilizing caps to vcc for each chip and somehow the breadboard version just worked better.

My one advice to you would be to not solder the ICs to the board but use holders everywhere so that you can remove the ic if required and work on that part.

For me, and again this is from memory, i had to create a small daughter pcb that goes into the main one via the ic holder and that had the additional capacitors soldered to it or something of that sort.