macbook pro a1707 dead

[jesi]

hi all techs

require some help on this 820-00281-A macbook motherboard came in dead and the pch bga U1100 (SR2NH), u5000 , Q7056 , U7000 and bios U6100 ,looks like these have been tampered with ..also the battery is swollen..

adapter usb c 20.5v 4.7a 96w , i persume it should power on mb without battery..

update:

when adapter plugged in , power switch which 3.3v on it , when power button pressed both fans come on after 6 secs for about 20secs approx then goes off , nothing on the display stays as blank.. the voltage at the usbc out start from 4.96v to 20.25v after 2 to 3 secs they drop to 19.77v

attached a photo of the mb with all the voltages on the top side which i managed to note down are wdotted down on the attached photo of mb,

i only get these voltages when the battery is disconnected and the adapter is connected, when battery flex is connected the macbook does not respond to anything no voltages except the usb c voltages

i was thinking of flashing the bios to start with but not able to find the right one for it , so have not touched until i get a repnse from yourside

these voltages i only get when the battery flex is disconnected from the mb

thankyou in advance

[mon2]

Check if PPBUS_G3H and 3V42 rails are stable.

[dariusgc]

Hello,

i've got the same mac. Want t know, maybe someone knows what normal resistance are on L7960 and L8000 phase inductors?

Thanks in advance. 🙏

[mon2]

These are low voltage rails so the resistance is expected to be low as well. Remove all power. Measure their resistance to ground and post the results.

[dariusgc]

Those two inductors show ~50 Ohms. Is it normal?

[mon2]

Yes. To me, these are ok.

What is wrong with the unit? What is the voltage to ground of PPBUS_G3H?

Also measure, ALL_SYS_PWRGD voltage to ground.