|"The chips on the motherboard all seemed pretty well set.."|
Did you try prying them or did you just look at them?
"Tried all the 16-bit slots, no dice."
"There is a speaker attached to the board but it gives me the weakest "blip" on startup, and a replacement doesn't beep at all."
That doesn't sound good.
"The guy I bought the board from insists it should be functional, and that he powered it up before shipping it."
Can you still contact him ? If so, ask him if he tried a video card with it.
"The system battery (2 lithium coins) are dead and removed, and likely weren't live when the board was successfully powered on before shipping. I don't think this would affect anything, could be wrong though."
The batteries must installed and be okay in order to retain bios Setup settings.However, that should not affect whether you can get video at all.
Does it say anything in the manual about how to access the bios ?
"Looking over the other jumpers on the mobo now. Power good signal? I'm using an ATX PSU with an AT adapter and switch, could that get in the way?"
I've never heard of such an adapter being used with an AT mboard. It didn't come with an AT power supply? Do you have an AT power supply ?
"What about the I/O wait state config? Should that be monkeyed with? "
"Just found the config page for the graphics card that worked with the board:"
Which mboard ? The subject 286 or another one ?
If you don't have a monitor with a 9 pin end connector (EGA, CGA, or mono), how do you know it even works ?
Same one here:
EXPERT COMPUTER INTERNATIONAL, INC
TOP SEGA 800
"JMP3 - Enhanced color display mode "
= EGA - Enhanced Graphics Adapter - 16 colors
The other setting is for Mono or CGA - Color Graphics Adapter - 4 colors
"(Pins 4 and 5 are jumpered as well...?)"
There may be more than one version of the board.
MONITER CONFIGURATION SELECTION
SW1/1 SW1/2 SW1/3 SW1/4 Enhanced Monochrome Color/Graphics
On Off Off On Color 40 x 25 Secondary Disabled
"DIP 1-4 - On off off On (First line, Color 40 x 25, Monochrome secondary...)"
That's the 40 x 25 resolution.
Pins 1 & 2, 4 & 5 closed
Pins 2 & 3, 5 & 6 closed
"JMP1 - 2+3 jumpered, 5+6 on JMP3 are jumpered, must match up? = 27256 Eprom BIOS selected"
"Doesn't that BIOS selection stuff sound fishy? Matches up with the BIOS on the motherboard..."
That's regarding the video card's bios chip, not the mboard's. Yes that must be right. Look for a 27256 chip on the video card.
Another one ? here:
TOP SEGA 800