Henry S. Courbis wrote:
Hello Steven.Does anyone have a suggestion on where to start debugging?I think you're on the right track to check all the programmables first. Next I would double check all the solder points. If you have an IC tester I would also check the rest of the logic.Are there any hobby-type device programmers that can handle the 74S571 and 74S287 PROM devices used on the DDT boards? Are these things tricky to program?Ah! You've found the biggest dilemma with 'hobby' type programmers - lack of broad range support.I checked my Advin software and it will program those older PROMs. You could send me the PROMs and I'll verify them for you. You could also keep an eye on eBay for a cheap Advin. Every now and again I see a Pilot-40 or U40 come up for sale for under $100. WELL WORTH IT! Then there's also some nut trying to sell one for $450 on eBay. Don't fall for his auction though. Really any of the U series are good machines. MVP too, but they're rare at a good price. I also have a 'loaner unit' somewhere around here in my office I could send to you if you'd like.
There's an MVP on eBay for $349.00. This is not a $349 problem, however :-).Do you know anything about the older "Sailor" programmer? They do a dance around providing any specs for it and are clearly trying to get folks to buy a recent model. Unclear whether the software is even available for it.
Steve