dbc, thanks for the reply.
Yeah, it's weird how the header connector on the board is 20-pin feeding a 15-pin D-sub at the rear of the case. I have the 15-pin, 3-row (5+5+5) connector from the elec. store (like shown in attached pics @ the 2nd and 3rd posts) and a 20-wire flat cable that fits exactly into the 20-pin board connector.
But, as you say, I don't want to fry my monitor guessing what goes where. Which is why I'm asking for help from you guys who know way more about this stuff than I do. Come to think of it, I do have an old monitor somewhere I can use as a guniea pig before I try the real thing.
Any more ideas how I might decipher this, by taking voltage measurements or other method?