a2289 820-01987 liquid damage

[jadao]

This liquid damage board was not powering on.
PPBUS_G3H rail was fluctuating between 12,56V and 12,23V and PP5V_G3S was following the same patern between 5V and 4,89V.
I cleaned/reflowed U9080 and U9000 area and compared some diode value with samet esting board.

After that 12,56V became stable and board chimed but it get stucked to apple logo for around 5 minutes to finally display the login session page, but the trackpad is slow and the system takes time to react whenI enter a false password.
During the time it is stuck on Apple logo, the mouse is on and it is responding to CapsLock keyboard key. PRAM is working, boot menu is accessible.

I noticed that PPVCCEDRAM_S0_CPU, PPVCCGT_CPU_PH2 and PPVCCGT_CPU_PH1 never come on. probably because OS is still not booted? (the progress bar comes after we enter the password and I don't have the password yet).

Not sure if I am looking for an ssd issue, a sensor issue or even worse, a cpu ram issue.

Besides trying first to get the password, backup the data and format do you have any suggestions?
Thanks

 

[2informaticos]

iGPU voltage will not come on even after loading macOS.
It only comes on when high load graphics is detected.

Save data in target disk mode and make DFU Restore.

 

[jadao]

I completed a dfu restore, now it boots to internet recovery but it is still super slow, the trackpad is not fluent and image is refreshing very slow from apple logo to internet recovery to wifi network selection...It takes more than 30 minutes just to accept wifi password, same thing with ethernet cable, i have 16hours remaining.
Is PPVCCEDRAM_S0_CPU also not supposed to show upunder normal light load?
Thanks

 

[2informaticos]

Usually not present on boot.
No idea when it comes up.

Start in diagnostic mode and see if any error pops up.
Fan spins to max?

 

[jadao]

Fan spins normally and cpu is normal warm.
Launching the diagnostic mode seems to take forever, after 1 hour it still increasing the time remaining, 2h, 6h, 9h, 16h, 24h, now it hangs on 24h remaining I don't see any improvment...
I will inspect again corrosion in general and near sensors according to schematics...

 

[2informaticos]

Thermal sensor should cause max spin fan.
An I/V sensor shouldn't cause the lag.

Just in case, test with known good battery.

 

[jadao]

I replaced the only two stuffed I/V sensors, replaced also U9080 and I9000 but no change.
I tested also with a known working topcase and battery and no change. Ultrasoniced as last resort to see if any improvment but still nothing.
I think it's time to stop spending time on this one, we can't fix them all
Thanks a lot anyways for you help!