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Post voltage for pins 9, 15, 26 of U7100 and F7140/41.
Also post exact value (measured onboard, ohm scale) for R7180/81 and R7185/86.
Check resistance between pins 17/18 and 27/28 (ohm scale) at U7100 too.
As i was measuring this, the R7020 blew up. I think i might've plugged in the charger wrong because there's no green light. have replaced it with another resister with the same marking "470" but still no green light. What did i do
R7020 usually gets burnt because of short in U7090, or one of the filter caps from its pin 6.
Seems to be U7090 in this case.
Also check for short, or low value at 3V42 rail; before and after U7090 is removed.
I don't think that.
Something else happened there.
Unless you used fake charger, which gives full voltage always.
Original Apple Magsafe 2 gives only 3V at the first moment, before the board is detected correctly.
Bench power supply also can generate such kind of problem.