At 03:10 PM 10/16/2004, you wrote: I looked into this and found that the people who fool around with old arcade video games have the same problem with EPROMs, here is one fellows' solution to using a standard 2764 PROM in place of the rare Motorola 68764 (which I think is the one on the KDF11-B quad CPU board). Haven't tried it though. I could never find the pin out of the Motorola part.... BTW, my PROM programmer had no problem identifying and reading the 24 pin DEC Prom, I guess if I could find a blank one I could burn it. Doug Taylor You Build It: Hero Rom UpgradeYou build it: Hero Rom Upgrade OK so you downloaded the new ROM version, but you cant find a 68764 (8K Eprom in 24 pin package). Well here is a little conversion you can do to allow you to use a 2764 (8K Eprom in 28 pin package). 1 tie high (+5) 2 tie to socket #21 28 tie to socket #24 27 tie high (+5) 24 Pin 28 Pin Notes -------------------------- Vcc 24 26 N/C OK to pass through A8 23 25 A8 OK to pass through A9 22 24 A9 OK to pass through A12 21 23 A11 Socket to prom#2, pin to socket #18 E 20 22 OE OK to pass through A10 19 21 A10 OK to pass through A11 18 20 CE Socket to prom#23, pin to ground