820-3476 dead board

[2informaticos]

PPDCIN_G3H is stable?
What about SMC_PM_G2_EN and 3V3_S5?
Be sure to use original 60/85W Magsafe 2 charger.

Just in case, test in SMC bypass mode.

 

[Soji]

PPDCIN_G3H is stable? yes 16.71-16.72
SMC_PM_G2_EN is not stable 0.7 -3.8
3V3_S5 is not stable -0.7-3.6
am sure my magsafe 2 charger is original
ON SMC bypass mode.
PPDCIN_G3H is stable
SMC_PM_G2_EN is stable 3.4v
3V3_S5 is stable 3.3v

 

[2informaticos]

Remove R8140 and check again SMC_PM_G2_EN.

 

[Soji]

Removed R8140 and check SMC_PM_G2_EN was unstable 0.8V and 3.2V

 

[2informaticos]

Any history available?

Check diode mode to ground at pins 13, 22, 29 of U7501.

SMC_RESET_L stable voltage?

 

[Soji]

there's no available history
pin 13 - 0.492
pin 22 - 0.570
pin 29 - 0.476
SMC_RESET_L - is 3V and it's stable

 

[2informaticos]

With R8140 removed, make short over C8142 pads and check if SMC_PM_G2_EN still fluctuates.

 

[Soji]

It’s a new day here got to shop to continue the test, with the resistor removed, and charger plugged, the processor is all warmed up, all unstable voltages are now stable, could we call that a fix or what??

 

[2informaticos]

Which "stable" voltages do you get now on the board?

 

[Soji]

PP5V_S5-5V stable
S5_PWR_EN does not fluctuates rather changes from one stable voltage to another- 1.8V - 2.3V stable
SMC_PM_G2_EN - 3.42V stable
PPBUS - 12.6V stable

 

[Soji]

Also after 20 - 30mins the processor cools down completely and
PPBUS still stable at 12.6V
PP5V_S5 still stable at 5V
SMC_PM_G2_EN still stable at 3.42V
S5_PWR_EN still stable at 3V
all these with R8140 removed

 

[2informaticos]

So processor gets hot even no S3, or S0 voltage present?
In such case, PCH is bad...

 

[Soji]

When I mean the processor was all warmed up, I mean the board I working , I've these following voltage present and stable with R8140 removed.
PP3V3_S5
PP3V3_S3,
PP3V3_S0,
PP5V_S5
PP5V_S4
PP5V_S3,
PP5V_S0,
Also after 20 - 30mins the processor cools down completely and
PPBUS still stable at 12.6V
PP5V_S5 still stable at 5V
SMC_PM_G2_EN still stable at 3.42V
S5_PWR_EN still stable at 3V
all these with R8140 removed

 

[2informaticos]

You didn't say anything about RAM, PCH and CPU core voltage...

 

[Soji]

The system is working now, booted to Home Screen. But the resistor R8140 still removed. What should I do now ?

 

[2informaticos]

Be sure 3V3_S5 is not present when machine is turned off, with only battery (no charger connected).

 

[Soji]

It’s not present.

 

[2informaticos]

test it few days, in different configurations.
With battery alone, wake up back from sleep, etc...