Last night I wired up a NES-TSROM board to work with EPROM's. Checked it for shorts, made sure connections were good, etc. Then I popped in Mega Man 3. Program was running fine, but background graphics were garbled. Sprites for the most part were fine. I thought maybe it was a bad burn so I popped in set for Mario 3. It ran perfectly. So I took those back out and put back in the Mega Man 3 ones (which I re-verified) and it was same story with messed up backgrounds. Now the weirdest part, I put the Mario 3 set back in and now that has garbled background gfx 
So I took it back to the bench and check and rechecked all the connections, made sure I had the pinouts right, but I find no problems. Any ideas?
So I took it back to the bench and check and rechecked all the connections, made sure I had the pinouts right, but I find no problems. Any ideas?
So problem solved.