Finally I got RAM bank 2 working on my SE/30. Lesson learned: replace ALL F258s, not just those that look damaged.
And maybe more exciting, we now have 256 colors. I was happy to discover that the Mac had a Radius Color card installed when I bought it. Unfortunately, the card turned out to have too little VRAM to display more than 4 shades of gray. So I bought a number of NOS ZIP VRAM and put in the card, and now: 8-bit color!
So finally I can play those old Sierra AGI games in color! Those games were my favorites when I was a kid and had a Mac Classic. Of course I wanted to play them in color, and I was so disappointed when it later (on my Performa 460) turned out that they can only be played on old Macintosh II models (pre the 32 bit clean ROM). Or an SE/30 (with the dirty ROM) + a color card. And here we are!
(For some reason Kings Quest I and Space Quest I still only works in B/W. But the rest works fine in 16 color)
As a 1400 and Duo fan I find this very interesting. I'd thought the name sounded French, but apparently it's based on veräussern: German for divest or dispose of? Tried different combinations using "dispose" of PowerBook display and hit on this 2005 article:
I'm wondering if the ADB KBD you're using might do the same kind of magic described for bumping the author's 12" PowerBook into external display only mode? Might be worth some tinkering? IIRC "Clamshell Mode" was introduced with the Pismo and dedicated all VRAM to the external display rather than splitting it between screen and external display. IIRC I was running at 1600x01200 in 24bit?
I'm thinking a hack of the Monitors control panel to deselect the internal display in some case specific manner might be possible given today's disassembly tools?
In the days of System 7 someone wrote a little piece of software called "veraeusser" to do exactly the trick you are asking for: Deactivate the internal display in a PowerBook while driving an external display. Unfortunately I can not locate a copy of this. Probably a fellow comrade will provide it to you. Please be so kind and post if (where) you found it. With best regards.