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Ok if you're for sure getting pulsing on all the power rails, I would try another BIOS just to see if that is the problem. Keep the original, but try a test BIOS from a donor 00165 to see if the machine boots.
Okay, I've gone back through checking the rails... PP3v3_S4 boosts twice the same as every other S4 onwards rail, but after the others boost twice, they drop to 0v. PP3v3_S4 drops to 0.45v and sits there.
The damage was in the U3210 area, so I swapped out U3210 to see if it made a difference.
I now get PP3v3_S4 and it seems like its on because the CPU is getting hot after a min or so and VCORE is a constant 1.8v