Regarding pinouts and connections. I already figure out enough info from CCPROM to emulate Bubble memory and GPiB, so real need for motherboard beeping with multimeter for emulator. BUT...! I really want to draw full motherboard schematic, so need much more beeping and access to physical motherboard. Theoretically it is possible to do it remotely via video call (no nudes, please!) with somebody, who have motherboard, patience and interest in reverse engineering. With schematics it looks possible to reverse PAL contents. One PAL IC is located near RTC TMS9914A and UART. It usually get damage from leaked battery. I thing I can figure out contents of PAL if I know all PAL's connections on motherboard.
Regarding revisions of 1101, I don't have much information how many revisions are on wild. I only saw two motherboards: one from 1100 and one from 1101. My research is based on 1101 board. Link to my
motherboard with IC identification. And
copy of my personal GRiD Compass folder online.
Other news: We are small international team on
Telegram with one Ukrainian (Author of
Compass for MAME), one Kazakhstanian (
Author of
GUI app for GRiD Disk editor), one Latvian (me) and 2 Russians (
Kirill (
youtube,
github) and
Yuri). Mostly speaking Russian, but we can switch to English, so everyone welcome. Slowly working on Raspberry Pi based GPiB FDD (and later HDD) emulator. Have some progress and have some fails, but looks like it is doable with some patience and time.