MacBook Pro 15" 2010 820-2850 no PPBUS_G3H, green light on

[vdrokko99]

Hello,

I'd like to ask help to repair 820-2850. There is green light, but not turning on because the PPVBUS_G3H is 0.5xxx V. I already measured resistance to GND, but no short ciurcuit. I did a few measure next to U7000,

R7020 ok,
R7050 ok,
F7040 ok,
SCM_RESET_L 3,4V
CHRG_DCIN 16V,
PP5V1_CHGR_VDD, and PP5V1_CHGR_VDDP is 0,5V but no short to GND

I think the missing PP5V1_CHGR_VDD is the problem which is comes from and go to the U7000.
This missing voltage means a defective U7000 or cause other missing voltage?

[vladimir1909]

Multimeter in diode mode and measure PP5V1_CHGR_VDD to GND

[vdrokko99]

Multimeter in diode mode and measure PP5V1_CHGR_VDD to GND

0.481V in diode mode, red probe to gnd.

[vdrokko99]

I noticed signs of previously maybe u7000 was replaced. So is removed and resolder. Now i have pp5v1_chgr 5V. Now ppbus_g3h is 4V.

Pin 27/28 resistance is 20 ohms
Pin 17/18 resistance is 2.3 ohms
Pin 6 CHGR_CELL 2.55V

aaand..

SMBUS_SLC_5_G3_SLC is pulsating 0-3.4V app. 1Hz.

[mon2]

Is F7040 removed? Suggest to remove it and confirm again if ppbus_g3h remains @ 4v. What is the resistance to ground now of ppbus_g3h?

[vdrokko99]

With removed F7040 is still 4V. Resistance to GND on F7040 Pin 2 is 12.2kOhm.

[vdrokko99]

I started to measure the voltage divider resistors for CHGR_CELL, R7012 is 1k as is should be but R7013 was 3kOhms instead of 1kOhm. I replaced to 1k, and now the voltage on CHGR_CELL is 1.7V

CHGR_CELL 1.7V is ok?

PPBUS_G3H is still 4V

[mon2]

Based on the resistor values, the CHGR_CELL voltage should be 50% of the source voltage of 3v3 so 1v7 sounds ok to me.

Noting this region to be a fault, what is the voltage to ground of CHGR_ACIN?

PP5V1_CHGR_VDD, and PP5V1_CHGR_VDDP is 0,5V

?? Not 5v0?

[mon2]

I would replace U7000 again. The PP5V1_CHGR_VDD / PP5V1_CHGR_VDDP are based on an internal LDO that feeds off of CHGR_DCIN and you have a valid voltage at CHGR_DCIN.

[vdrokko99]

Sorry, PP5V1_CHGR_VDD is 5,0V, sorry.

Today i will order 10 pcs of ISL from AliExpress. I will replace again. Thanks for advice, as soon as arrives the new chips, and replace, i will post.

[mon2]

Test the voltage to ground of:

SMBUS_SMC_BSA_SCL
SMBUS_SMC_BSA_SDA

at battery connector J6950. Still suspecting a defective ISL @ U7000 based on the lower than normal power up voltage.

Also review the DCin mosfets used by the ISL @ Q7080, Q7085.

Remove all power and test their resistance as normal:

source / drain
source / gate
gate / drain

of each.

Are you using a true Apple charger?

What is the voltage to ground of PM_BATLOW_L? If this signal is LOW then the power adapter is not suitable for this logic board.

See the flow chart here:

https://logi.wiki/index.php/G3_to_S3..._and_Broadwell

U7000 is still the key suspect.

[vdrokko99]

https://logi.wiki/index.php/G3_to_S3..._and_Broadwell

CHGR_CELL should be 3.42V, but usig 50% voltage divider, this value is not passible.
So i started to googlin' for a hi-res picture of the logic board and seems like there is no R7013
If no R7013, no voltage divider. I will remove R7013 and I will measure PPBUS_G3H again.

[vdrokko99]

I removed two resistor, R7013, and one more, i dont remember the exact name, both of them are non-exist on the picture shown. And a board starts. Every voltage was ok, but black screen. After C9560 replace, looks good. There is picture, and boot. I don't understand why R7013 exist on schematic. Thank you for your help, and advice!

[mon2]

Here is how I understand this chart:

If the battery pack is with

1 cell; then DO NOT stuff R7012 and DO NOT stuff R7013 = floating / open line
2 cell; then DO NOT STUFF R7012 but stuff R7013
3 cell; then stuff R7012 but DO NOT stuff R7013

This strapping of resistors will define the battery pack charge voltage and currents.

Well done on your repair!