Going to call this one solved.  Was able to move another monitor to the misbehaving SC1430. Plugged into the VGA, this monitor showed the text only BIOS messages. Unknown why the other monitor wouldn't display the ES1000 text mode video signal, but would display the 8400GS text mode video signal. Another mystery of the Bermuda Triangle.  I guess with an oscilloscope I could figure out what the problem was.  Is the ES1000 a bit off frequency, so the big monitor couldn't lock on perhaps? 
Something has happened to my SC1430. Was trying to get into the bios to adjust settings, except reboot does show BIOS spash, or anythings. Yet when GRUB starts up, using a graphics mode, that shows up, and it can go all the way into Linux.  When I boot, it does much of what usually went on, except the monitor is black.  No blinking cursor.  Just black. Diagnostic LEDs changing during POST, until they eventually quiet down to just 1,2,3 solid on  (Manual says ensure disks properly connected). But where I think I am is in the BIOS menu, except with a blank screen.  . ctrl-alt-delete reboots. F1 boots my boot partition (bringing up GRUB), or the CD (booting a KNOPPIX CD). In case there was some sort of BIOS disable, I tried the PSWD/RTCCLR jumper procedure.  All that did was make it so I had to use F1 to boot, instead of the  old boot sequence. It's like the vga no longer has a text mode, or like it no longer has a font built in, so all characters are black.  (Sort of doubt that's it, because I think a cursor would show though even if fonts were blanked). The text mode display that lived at memory address 0xB000:0000 back in the days of DOS. Booting a MEMTEST86 CD flashesh the drive lights like it's working (flashed CD drive, no hard disk activity), so I suspect that it'd text mode display is blacked too. This really feels like the built in graphics chip no longer supports text. Is there something that makes a SC1430 act that way, and how can I fix it? I wish I had a plain PCI SVGA card to try that. 
SC1430 boots without text mode display, can display when linux boots.