Macbook 820-3662-A PP5V_S4 Missing. Green/orange light no power

Laimis

New member
Hi guys, working on 820-3662A logic board. Green orange light is on when charger plugged in but no power. PP5V_S4 missing. Checked P5VS4_EN and its missing. It comes from u8170 S4_PWR_en where pin 2- PM_SLP_S5_L is 0V. A little bit strange as P5VS4_EN= 0.07V but S4 PWR EN= 0V. Where does the 0.07V comes from? Chip U7501 itself ? Any help?
 

Laimis

New member
HI MATE,
PPBUS_G3HOT =12.56V
​​​​​​SMC_PM_G2_EN=3.38V
PP5v_S5=5V
PPVRTC_G3H=3.3V

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dukefawks

Administrator
Check U7501 area for corrosion especially pin 23.
131 on 3V3 is normal so if no corrosion and G2_EN and P3V3_S5_EN present U7501 is a good suspect.
 

Laimis

New member
ok quick update. I have managed to turn the board on with holding power button on-removing charger while holding button-and plugging charger back in while holding button still and it turned on. so fans started to spin but no chime or video. i was measuring around u7310 as there was no power from L7310, l7320,l7330 and u73010 had power present but nothing on output. then i touched pin 40 with pin 39 by accidend and now i bumped into another problem as dont have PPVIN_S5_HS_COMPUTING_ISNS. when i touched them two pins board switched off and now PPVIN_S5_HS_COMPUTING_ISNS= 0.5V what the hell have i F***ked up. any ideas what was wrong when it was working with no chime and what have i shorted now? please dont judge as i am just enthusiast with repairing not professional.
 

dukefawks

Administrator
Pretty sure you shorted out U7310 and put PPBUS on the CPU. This is fatal, the end dead CPU in 99% of the cases. U7310 is dead for sure at least now.
 

Laimis

New member
ok so changed u7310,and it PPVIN_S5_HS_COMPUTING_ISNS=12.5V. Board switches on with keyboard bypass(holding pwr button/removing charger,attaching charger again /reease button and press again)
PP5V-s0 present, PP3V3_S0 present but no chime and no video as it was before. Gonna check power rails whats missing. any ideas what to check first or why it only switches on with bypass? thanks.
 

Laimis

New member
But it was exactly the same after liquid damage, before i messed up with it. Is it worth trying to check it? maybe cpu is not dead after all? any specific ways to check cpu?
 
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