OK, I know Williams doesn't like this, however Ted Estes hasn't got the info I need so here is my problem: Williams produced a Test ROM (2532) that covered system 3 - through 7 and the image is split in two. 0000 - 07FF is for the earlier games (two LED indicators) 0800 - 0FFF is for System 7 (seven segment display) Using this in a game like Black Night (second image used) shows a count from 0 - 9, and then the display blinks twice and shows a steady 0. All the tests from 0 - 9 seem to emulate the same tests that BK shows in the little book, however what is NOT documented is the double blink! I thought it might be an interrupt test, but the IRQ timing is correct... What I have is two seemingly identical boards - one that boots fine and the test shows the correct sequence, and a second that counts correctly but won't do the double blink nor does it boot. Fluke 9010A claims RAM ROM and I/O are fine. (in case you were curious) So what I am left with it trying to figure out what the double blink portion of the test was. Ted Estes thought it had no meaning - but he had never been able to find the docs on this test Eprom when he worked at Williams (seems to have done a thorough search!) - but now he is not so sure. So I am trying to disassemble the Eprom image (800 - FFF) in an effort to find what that test might be. Unfortunately I am NOT any good at this and was hoping that someone with experience in this would be interested in helping document this Test Eprom. Sections of it make sense to me, like RESET clears all the PIAs, but then it wanders off to check the contents of assigned RAM locations and I don't know how to track this efficiently...but am happy to provide a table of ROM/RAM and I/O ports. This is a 6800 based system (6808) with five 6821's, one IRQ generator (1k077hz) running at 1Mhz. I have the Test ROM from Two Bit, it is the same Williams program for the 1st half (0-7FF), the second (800-FFF) is different though, and not very well documented... Thanks if anyone can help... John :-#)# Thanks!