820-00165 Green led but not start

[raainxx]

Hi, i have this board no liquid spill, i have PP5V_S5 = 1,2V, in diode mode 0,447 (bad), i try to change U7501 but same problem.
i don't understand where the PP5V_S5 is generated, by U7501?

 

[2informaticos]

Why do you think 447 is bad?
Doesn't look low at all.

Do you get SMC_PM_G2_EN and correct PPBUS_G3H?
Check 5V_S5 disconnecting trackpad flex.
If still bad, change U7501.
As last step, change U7400 if needed.

 

[raainxx]

PPBUS=8,59V
SMC_PM_G2_EN=3,41
sorry i say bad for 1,2V i have just the board with magsafe board and cable flex.
i remove U7400 same problem, i change again u7501 and i come back

 

[raainxx]

Same with another U7501 PP5V_S5 1,2V
i try to remove U7400 and L4820 but no change

 

[2informaticos]

I hope you didn't power up the board without U7400!!!

Remove C7505, C7410, C4810 and check again 5V_S5.

 

[raainxx]

i power up the board without U7400, is it dangerous? because i haven't PP5V_S5. i dead the board?
I remove C7505, C7400 instead of C7410, C4810, same 1,2V on PP5V_S5

 

[2informaticos]

CPU could be fried now.
Post diode mode to ground at L7430.

 

[raainxx]

ok...
L7430= 0,151 in diode mode

 

[2informaticos]

Doesn't look bad, you could be lucky.

Check diode mode on all 3V3 and 5V power rails; from S5 to S0.
Check all traces, solders and components around U7501.

 

[raainxx]

I check all rail 3V3 and 5V
PP5V_S5=0,465
PP5V_S0=0,412
PP3V3_S5=0,564
PP3V3_S4=0,381
PP3V3_S3=0,465
PP3V3_S0=0,341
PP3V3_S4SW=0,486
i check trace nothing, solder and component around U7501 seems good, i compare with another board.
Maybe i use bad U7501 from donor board?

 

[2informaticos]

Post some U7501 voltages; pins 23, 22, 12, 13, 29, 21.

 

[raainxx]

hi 2informaticos, U7501 pin 23=8,59, 22=4,57, 12=3,42, 13=1,47, 29=1,126, 21=3,40

 

[2informaticos]

"22=4,57"
Are you really sure?
If yes, change U7501.
There is 3.3V LDO output...

 

[raainxx]

ok thanks, i solve the problem, i think i remove by mistake C7503, when i change U7501 the first time.
Now the mac work well.

 

[2informaticos]

"Check all traces, solders and components around U7501.
-------------------------------
i check trace nothing, solder and component around U7501 seems good"
Pay more atention in the future...