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Maybe my test screen is damaged. When I shorted the 3v to R1431 it just gave me a grey screen again. Connecting the customers screen gives me a nice crisp image. :) Is running a jumper an acceptable repair, or should I be repairing it somewhere else? It seems like EDP_PANEL_PWR comes from the CPU.

Tested with a known working board. R1431, on the good board goes to 3.3v. On the faulty board it stays at 0.3mV. Does EDP_PANEL_PWR come from the CPU? I jumper R1431::2 to a 3v rail, I can see the LCD panel reacting. No bkl though, so not sure what is doing. Will that initiate the image...

If I touch R7789::2 or Q7707::3 with tweezers the back light turns on, but only if I'm earthed to the board somewhere... R7789::1 = 8.32v ::2 = 8.19v

Not that I can detect. I sort of think my finger is shorting something when I press on Q7707.

Hi Duke. No history. Was given to me by another shop who didn't recorded anything. Board looks spotless. Known good test screens. L8304 reads 0.02v consistently. Maybe my DM isn't quick enough to get the pulse.

Works with an external screen. If I press on Q7707 I get a backlight with a white screen. Only works when pressing with my finger though, not a spudger or tweezers.... I tried just flexing the board too in case that's what I was indirectly doing. Either way, when I get a backlight, there is...

Actually, mark this one solved. When I saw the above measurements I swapped the DC Board and it worked fine. Thanks again TCRS.

Thanks TCRS, I've been focusing on programming this year and have forgotten the thought process for some reason. PPBus = 12.59v SMC_BC_ACOK = 3.490v U6901 has 3v42_G3H and 3.4v on ::1 and ::2 U6900::1 = 3.4v ::4 = 3.4v ::5 = 15.879v

Works fine off a charged battery. Missing PP3v3_s4 and then PP5v_S3. C7800::1 = 2.5v C7800::2 = 0.480v. Q7803::1 = 0v Q7803::3 = 3.24 Q7803::1 signal comes from U7970::4 which seems to be 0.0v Any suggestions on where to look next?

The charging works okay on this one now but it kernel panics when left on for awhile and feels really hot, but the fans aren't spinning high. Any suggestions? External boot has the same result.

At U1950, the only signal present is PP3v42_G3H. But the sys isn't powered, so that is right for right now? Swapped out U1900, same behaviour. This board might just be a rabbit hole. It has mild corrosion across the entire board.

U6100 traces beeped out and resistors all checked already. Will replace U1900/50 and report back.

The board had a liquid damaged IO board which I replaced. It had a dot of corrosion around Q1840 and R2898. It was starting up and running but would turn off from time to time and not turn on again for while. Sent it through the U.S. machine and now it's missing VCore, but it turns on every...

Light stays on now, but the board turn on every time I connect power when the battery was left connected. Runs off batter fine.

What's the purpose of a cap that is between two power rails? Does it work to balance the voltage on both sides?

I did check that cap already, but measuring again showed big voltage drop to ground. Obviously didn't check it properly. I removed it and it's been happily charging a battery for 15 minutes. Might have solved it.

Louis, is there something about the thermal camera you need to share with us? You keep mentioning it to me. :D PP3v42_G3H reads 0.003 in diode mode. Put power on that rail, the draw starts high and goes straight down 0.04a... Again, the short is gone and the board works.

Initially I get a green and orange light, which goes out after about five minutes of charging. Once the light is out, the board seems to have a short on PPBus which is around 2v. If I inject power on PPBus the short goes away and I get a green light again. It runs fine until I try charging it...

Doesn't seem to turn back on with the trackpad and keyboard disconnected. But it won't sleep still. Will investigate the behaviour a little further quickly.

No liquid damage, just wouldn't turn on. But it was quite dirty. Thanks for your help. I haven't tried with a known good TP and KB, will disconnect them for now. It actually doesn't sleep when I shut the lid. It spins for awhile then turns off completely.