After reading this entire thread, I would like to second Porter's excellent question that would put an end to all the speculation:
What component smoked?
I know the starter of this thread said that "smoke came from the analog board" and that he could not find any "charred remains." But if smoke was indeed seen coming off the analog board (with the case open, naked analog board in crystal clear view), then something on the analog board indeed caused it. And close examination of all the analog board components with a magnifying glass should reveal that. Brown and black burn marks should be visible on the source of that smoke.
Since your Mac is dead now anyway, you could just connect it back up again, and smoke it a little more to make it more visible.
Unless you find out what was burned, you will likely spend considerable time troubleshooting the board or considerable money swapping it out. Find the source of the smoke, replace the bad components, don't do it again.
What component smoked?
I know the starter of this thread said that "smoke came from the analog board" and that he could not find any "charred remains." But if smoke was indeed seen coming off the analog board (with the case open, naked analog board in crystal clear view), then something on the analog board indeed caused it. And close examination of all the analog board components with a magnifying glass should reveal that. Brown and black burn marks should be visible on the source of that smoke.
Since your Mac is dead now anyway, you could just connect it back up again, and smoke it a little more to make it more visible.
Unless you find out what was burned, you will likely spend considerable time troubleshooting the board or considerable money swapping it out. Find the source of the smoke, replace the bad components, don't do it again.