This issue also causes the machine to power on with no video? I'll give it a try anyway, thanks. I remember reading about this somewhere before, but I forgot where to look for the right info.
If I manage to fix one motherboard with this, I should be able to assemble at least one working 'book. Let's hope I didn't nuke anything with the heatgun. I have done that fix many times before (mainly nVidia) and never killed a mb yet.
Maybe this is the issue on my "only-booted-2-times" Powerbook G4 aluminum,too (vreg chip)?