820-3115-B powers on briefly, corrosion near ISL chip?

[Hardwood T/S]

Hey! This time I actually have a 2012 13" board, 3115-B. Similar problem to last time, except this guy gets no power even with battery plugged in. When AC adapter is attached, sleed LED lights and fan spins for a quarter-second, then rests. Board does power on in SMC bypass mode.

Board had corrosion near the ISL chip, specifically northern part of chip and above components--cleaned with IPA and resoldered to remove corrosion on pads--nothing. 3v42 is stable, however rails such as SMBUS_SMC_5_G3_SCL and SMBUS_SMC_5_G3_SDA phase up to ~3.475 and then down to ~3.445, seesawing back and forth. Should I try replacing ISL?

Measured the resistance of the northern components that had some corrosion against a good board, all checked fine.

 

[Hardwood T/S]

Checked the pins, 9 was at ~30.5mv, which was about ~3mv lower than a working board, and 15 was at .1mv, which was .2mv lower than my working board. Can't get a great reading on pins 17/18, but pins 27/28 are normal resistance. R7052 and R7051 read correctly, as does C7050. Thinking 17/18 may still be an issue tho, any ideas?

 

[2informaticos]

"Can't get a great reading on pins 17/18"
Why great?
You must read aprox 003 there...

Check pins 9 & 15 when board is on in SMC bypass.
Also check all sensors output from page 50 and 49 too.

 

[2informaticos]

"(C7000/1) are not showing any ohms in resistance, and 0.00 in diode mode"
Can you post exact values in ohm scale and diode mode too?

 

[Hardwood T/S]

I know the correct value, I'm asking you if the correct action in this case would be resoldering jumper wires from R7501/2 to pins 17/18 instead of replacing U7000 or not, since I'm already jumping the pads of R7051 and previous attempts at the jumper wires yielded varying results.

and what about R5280? Not sure what could be creating a lower voltage on that SDA line, U7000? I can only assume, since U7000 is the first start on that line when battery isn't plugged in--pin 10 creates that dataline from G3H, yes?

 

[Hardwood T/S]

Replaced U7000 on the board with C7001 showing 0.000 on diode mode, now R7051 is showing wacky resistance--why does this guy fail so often?

 

[Hardwood T/S]

Will do! I'll probably try tomorrow, I'm soldering on my knees and in the dark here... getting some microscope lenses in tomorrow hopefully!
C7001 doesn't show short anymore, but the board isn't powering on and dim light on charger still... I'll check the power rails and some more ISL stuff to see what the issue could possibly be.

 

[Hardwood T/S]

Turns out my C7001 board had a misaligned jack connector... well, that one is fixed. I hate people who strip screws.

Alright, so that leaves my 17/18 board in the dark still, I honestly think I probably toasted it somewhere and I'm running out of known good ISL chips to use.

The other board I have that won't detect the battery, the one with low voltage on R5280 SDA line, around ~1.5v, you think replace ISL? Not sure where else to go from there, maybe replace D6950, tho the SCL line is fine... which is why I think ISL.