Soldering while it was on?! Why were you doing the 12v mod on a falcon? Did it allready have an RROD previously?
Not soldering, just bridging the two points with DMM leads hooked together at one end. One of the tips was broken so it slipped and shorted the points. I was doing the mod so that I would never have the RRoD in the future. And no it didn't have it before that I know of.
or you could have damaged the temp sensor, or if you have an xclamp mod, the heatsinks are too tight/loose/no paste etc.
Wheres the temp sensor? Any way to test that? No xclamp mod just yet, but I was going to do it. Again, as prevention, not because it had problems before.
Second error, you have shorted a power rail and probably blew one or more of the mosfets in the process.
Is there a way to test those with a DMM?
It probably is fixable, but I doubt you are the man to do it after that tale. :-P