820 2936-B no green light, PPBUS_G3H 12.29v

[guzq]

Hey Guys,

Working on 820 2936-B with no green light, not recognized battery also, no visible water damage.
Already replace ISL6259 and SMC (twice) from donor board, No changes !!

This Mac draws 0.020-0.023 Amps at 16.5V, PPBUS_G3H 12.28~12.30v, what more could be the problem of 12.30v ?!


Here my measures:

PPDCIN_G3H : 16.48v
PPBUS_G3H : 12.28~12.30v
PP3V42_G3H : 3.475v
PPVRTC_G3H : 3.475v
PP3V3_S5 : 0v
PP5V_S5 : 0v

U6900:
Pin 1: 3.472v
Pin 4: 2.898v
Pin 5: 2.889v


U6901
Pin 1: 3.330v (SMC_BC_ACOK)
Pin 4: 3.472v
Pin 5: 3.475v


U7000
Pin 2: 16.11v (CHGR_DCIN)
Pin 3: 3.912v (CHGR_ACIN)
Pin 4: 3.473v (CHGR_VFRQ)
Pin 12: 3.475v (PP3V42_G3H)
Pin 13: 3.475v (CHGR_RST_L)
Pin 14: 3.331v (SMC_BC_ACOK)

Got really weird issue here, with pin14 U7000 give 3.3v, try replacing u7000 & SMC (twice from donor board) still no good result.

Checked R7051, R7052, R7021, R7022 all value normal

 

[2informaticos]

First of all, welcome to the forum!

Are you using original 60/85W charger?
Did you check PPBUS_G3H with board alone on the desk?

Post voltage and diode mode to ground at SCL/SDA lines of battery bus.

 

[guzq]

First of all, welcome to the forum!

Are you using original 60/85W charger?
Did you check PPBUS_G3H with board alone on the desk?

Post voltage and diode mode to ground at SCL/SDA lines of battery bus.

I'm using original apple MagSafe 60W
Yes, I'm checkin PPBUS_G3H LogicBoard alone on the desk.

Voltage & Diode mode to GND SCL/SDA lines of battery bus
R5280: 0.506 / value 2K / 3.475v (pin 2)
R5281: 0.507 / value 2K / 3.475v (pin 2)

Try using with full charge battery, BIL connector and LogicBoard still not turn on

 

[2informaticos]

Do not quote an entire post, visible few centimeters above.
Maintain forum aesthetic please.

Let BIL disconnected, until get the board working correctly.
Did you try another DCIN board?
Check continuity from U6900 to central pin of Magsafe connector on DCIN board.

 

[guzq]

Try it with another DCIN board still no good result.

There's continuity from U6900 (pin5) to central pin MagSafe DCIN board.

SMC_RESET_L - 3.475v
SMC_PM_G2_EN - 0v

 

[2informaticos]

Looks like SMC issue.
Check R4901/09/99.
Be sure to get oscillation at Y5010.

 

[guzq]

Checked R4901/09/99 all value normal.
I can't check Y5010 because don't have oscilloscope but voltage at both pins 1.6v

Try replacing SMC for last time from donor, issues still persist. PPBUS still 12.29v
I'm suspicious with U1800 (MPCH), looks like i'm gonna give up for this board.

IDK what else to do...

 

[2informaticos]

Mising Magsafe light and incorrect PPBUS_G3H at same time, points to SMC problem.
PCH is not involved in these.

Check correct ohm value for R6929.

 

[guzq]

R6929 value 2K, with 2.894v pin1 and 3.467v pin2

 

[2informaticos]

Replace U6900...

 

[guzq]

U6900 replaced, issues still persist...

 

[2informaticos]

Possibly leakage inside copper layers.
SYS_ONEWIRE should be higher, 3.3V aprox.
Disconnect DCIN board and check again voltage at pins 4 & 5 of U6900.

 

[guzq]

Disconnect DCIN board and change it with other DCIN board.

U6900
pin4 2.894v
pin5 2.884v

Try compare with working board, U6900 pin4 2.923v / pin5 2.915v

Taking 0.030 Amps now and SMC_PM_G2_EN - 0.145v

 

[2informaticos]

Missing SMC_PM_G2_EN is also SMC related.
Do you have SMC_RESET_L now?

 

[guzq]

Do you have SMC_RESET_L now?

Yes, i have it...steady 3.4v

U5010 measures:
pin1: 3.470v
pin4: 2.829v
pin5: 3.472v
pin6: 3.472v
pin7: 3.467v
pin8: 3.3v

I replaced SMC again, still no light, PPBUS still 12.28v

I try reball SMC to another board to test it, green light and fan spinning...
I ran out of ideas what should i check next...