Anyone taken the time to do this yet or is it already documented somewhere? Couldn't find it last night, so what better to do on a cold snowy evening but analyze schematics? Anyway, here's what I found so far - any documentation to add or corrections to sleepy analyzations? ROM space 7U:$0000-$07FF 7V:$0800-$0FFF 7W:$1000-$17FF 7Y:$1800-$1FFF 7Z:$2000-$27FF Fluke 9010a checksum values by ROM 7U: FFDE 7V: 4055 7W: FCD2 7Y: 1241 7Z: 44E1 RAM @ 7P and 7N 1KX8 total space 7P lower four bits (D0-D3), 7N upper four bits (D4-D7) $4000-$43FF RAM@ 3H AND 3F (Video RAM) 1KX8 total space, 3H lower four bits (D0-D3), 3F upper four bits (D4-D7) $5000-$53FF RAM@ 4F AND 5F (Object RAM) 256X8 total space, 4F lower four bits (D0-D3), 5F upper four bits (D4-D7) $5800-$58FF I think there are more RAM locations (the board location fails me right now) and I havn't looked for sound and dip locations. Can anyone add to this? Thanks, Greg