820-00165

[Neil250]

Intermittent green light on charger (randomly come on) with fan spin for a few seconds then off.
Since then, no green light.
Swapped DC in board and LIO cable, no change

PPBUS_G3H: 8.19 V
PP3V42_G3H: 3.43
PP5V_S4RS3: 0V

U7501:
4: 0
12:0
21:0


So no enables on U7501.
I though it was the DC in board but the connectors look good.
No corrosion
No water damage.

U7100
2: 14.10
14: 3.42

 

[2informaticos]

"PPBUS_G3H: 8.19 V "
SMC doesn't talk with U7100.
Check SMC_RESET_L firsy...

 

[Neil250]

SMC_RESET_L: 0V

Checked at:

U5110:
PIN 5: 0 V ---> PIN5 does not look good
1: 3.42

R5100: 96 kO
1: 3.42 V
2: 0 V

Worth replacing U5110 as a try or is this the SMC?

 

[2informaticos]

Remove U5110 and see if reset goes high.
If yes, replace the chip.

 

[Neil250]

OK replaced U5110

SMC_RESET_L now: 3.40

no green light or fan and of course PPBUS_G3H is now..... 0V

 

[2informaticos]

Why "of course"???
What you did there?
Post diode mode to ground on PPBUS_G3H.
Post basic voltages for U7100; 1, 2, 3, 9, 12, 13, 15, 19, 20, 27.

 

[Neil250]

Post diode mode to ground on PPBUS_G3H: .142 V

U7100

1: 13.77-13.99V
2: 13.10-13.75V bouncing
3: 0
4: 3.33
9: 0.03
12: 3.43
13: 3.39
15: 0.047
19: 5.08
20: 5.07
27: 0

U7100
pin 3 is 0, should be 3.2
pin 3 is short to ground in diode mode.

R7110: 93K
R7111: 1.6 ohm ----> should be 46K and I checked multiple times, the resistor looks good


resistance
27-28: 20.5
17-18: 3.5

Pin 3 U7100 short in diode mode, replace U7100?

 

[2informaticos]

"Pin 3 U7100 short in diode mode, replace U7100? "
Why so fast?
Remove C7111 first; if still short, replace U7100...

 

[Neil250]

Thanks!!

C7111 removed. Still short on pin 3 U7100.
Replaced U7100.
Replaced C7111

It worked.

Green light, fan spin.
Boots into OSX

 

[2informaticos]

"Replaced C7111 "
Any reason to do that?

 

[Neil250]

i removed it, i put a new one back
Do I not have to do that?

 

[2informaticos]

Why to replace, if was good?
No need to put back original.
Just try to work in a logic manner (for the future)...