820-00138 turns on, battery error symbol, then turns off. Works fine in SMC bypass

[kevinklinkmuller]

820-00138 turns on, battery error symbol, then turns off. Works fine in SMC bypass. So sensor issue? How do I sort sensor issue.

[2informaticos]

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.

[kevinklinkmuller]

U7100
pin 9 - 0.030v
pin 15 - 0.065v

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

[kevinklinkmuller]

im getting 20v on the DCin side and 15v on pp20v

[kevinklinkmuller]

ppbus on D7005 is only on 0.5v

[kevinklinkmuller]

thermal cam showing r7020 heating up and u7090

[2informaticos]

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.

[kevinklinkmuller]

before and after removal the 3v42 rails are quite low. 10 ohms short to ground, so must be a cap, should i inject voltage and see what heats?

[kevinklinkmuller]

SMC heats up.......... oh shit

[kevinklinkmuller]

did i really fry the SMC by plugging in the charger at a slight angle ?

[2informaticos]

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.

[kevinklinkmuller]

I used a bench power supply. Damn!!!!!

[2informaticos]

Every day can learn a lesson; but sometime can be pricely...
Next time when you use bench power supply, set it at 3V and go high to nominal voltage after Magsafe is correctly connected.

[kevinklinkmuller]

thank you! Going to reball an SMC and put that on next week. that should bring me back to where i started right?

[2informaticos]

At least at the last point before the "tsunami"
Or even better, in case if SMC was the culprit; which I doubt...