After successfully completing the 640x480 mod, I thought the next step would be to try oevrclocking the LC575 board (http://gabezing.sytes.net/lc575-40mhz-e.html).
I used a 21.7 Mhz oscillator, and that did not work. One problem is my RAM is 80ns. I got chimes, but no video (black). Since I don't have any 70ns VRAM, I tried to undo that change. I snipped the oscillator away and put my LC575 board back in the CC.
That's where my latest problem begins: I have no chime, no video, and only initial hard drive spinup (no OS load).
So I checked to make sure there wasn't any cold solder on the board. I removed the battery for about an hour (to zap the PRAM), and re-seated the RAM and VRAM.
Still no go. Can anyone think of anything I haven't done?