A1708 820-00840-A no power

[2try’s]

I guess i need wait until i have the chip to change to continue work on this board. Thank you for your help, I’ll update thread if new chip will change something

 

[2informaticos]

Board should work without U2800.
But you lose USB activity once macOS is loaded.

 

[2try’s]

Well i found chip anyway but yeah it worked the same without it
Now i have 20v and 0.137A on usb-c tester, machine have no image but fan starts to spin for a moment and trackpad is clicking, g3h s0 rails are working fine but i findout that my cpu rails are missing

 

[2informaticos]

Tell us which exact big coils get voltage.

 

[2try’s]

L7030 - 12.08v
L7430 - 0v
L7410 - 0v
L7420 - 0v
L7210 - 0v
L7220 - 0v
L7370 - 0v
L8060 - 1v
L7900 - 1v
L7960 - 0.956v
L8030 - 1.2v
L8410 - 0.005v
L7690 - 3.3v
L7670 - 5.1v

 

[2informaticos]

L7370 not pulsing at all?

Check ohm resistance to ground on CPU coils which don't get voltage.
Compare readings with good board.

 

[2try’s]

L7370 is not pulsing, only 0V
all resistance looks fine except
L8060 - 31 ohm
L7900 - 39ohm
didn't have good board but found pdf of values to ground on coils

 

[2informaticos]

I mean CPU coils with 0V actually...

 

[2try’s]

Readings on cpu coils is okay

 

[2informaticos]

Try known good BIOS.

 

[2try’s]

Same reaction

 

[2informaticos]

Then bad CPU...