820-3476 dead board

Soji

Member
board came in dead, it had fluctuating voltage
PPBUS_G3H was fluctuating between 12.2V and 12.6V
PP3V42_G3H was stable
PP5V_S5 was fluctuating 4.2V and 1V
S5_PWR_EN was fluctuating between 3.3V and 0.8V
 

2informaticos

Administrator
Staff member
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

Member
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
 
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2informaticos

Administrator
Staff member
Any history available?

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

SMC_RESET_L stable voltage?
 

Soji

Member
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
 

Soji

Member
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??
 

Soji

Member
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

Member
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
 

Soji

Member
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
 
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Soji

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