So... Keeping in mind that I'd had my 9010 for all of two weeks... I have started to develop a decent sys80 program, and that is the board set that I am focusing on for the moment. One particular board that I had was showing a bus failure. Sometimes I would get bit 1 stuck, sometimes bit 7. At first I could not figure out what was going on, so I set it down for a few days. I went back to this board tonight and for the heck of it, re-tested it with the ROMs removed. Luckily, that was the problem. However, there were some TTL chips that could have also been the problem. In general, when you get a bus failure, what's your approach? How to you try to narrow it down? I was trying to use my DMM to find a short on some of the FF that are on this board. Any other tricks? Just curious. --James Bright www.QuarterArcade.com Restored Arcade Games for your Home