Macbook 820-00923

[Instafixx]

Hello,
We have wrecked a Macbook Pro 820-00923.

The Macbook came in for a LCD Replacement. So we went ahead a performed a LCD only repair to find out that the Camera was showing as "Camera not connected". Upon diagnosis and checking through a couple of days we were able to isolate the problem to the flex beside the camera beneath the lcd. We may have damaged it while removing the LCD.

We used jumper wire to jumper the flex hoping to get back the Camera but i think we wrecked the board. The board isnt booting up now. It is drawing 20 Volts on the Amp Meter and evening drawing upto 1.3 to 2.5 A. The keypad works. The fan spins doesnt spin initially. The CPU becomes very hot.

I think its the Camera Jumper that have wrecked it.
WHile checking the J8500 i found one thing

With nothing connected to the board and charger connected there was no voltage at
PP5V_S0 and PP5V_S0_ALSCAM_F


Any help in this regard will be very grateful.

@mon2 @piernov @reformatt

[mon2]

Re: Macbook 820-00923

CPU is very hot with the heatsink ? Or without the heatsink ?

Yes, CPU will be hot without a heatsink. This is normal.

Remove all power -> what is the resistance to ground of PPVCC_S0_CPU ?

What is the voltage to ground of PPBUS_G3H @ F7000 ?

[Instafixx]

Re: Macbook 820-00923

CPU is very hot with the heatsink ? Or without the heatsink ?

Yes, CPU will be hot without a heatsink. This is normal.

Remove all power -> what is the resistance to ground of PPVCC_S0_CPU ?

What is the voltage to ground of PPBUS_G3H @ F7000 ?

CPU isnt very hot. Its normal heating. The heatsink is there.

PPVCC_S0_CPU checked at C10G1 .

Meter is Resistance Mode (Omega Sign) 5.08 ohms
Meter is 2K Mode (Analog Meter) its 0.05.
(Both Images attached)

PPBUS_G3H at F7000 is 13.02V

[mon2]

Re: Macbook 820-00923

Switch the (first) digital meter to the lower 200 ohm scale and measure again. The resistance looks ok for the CPU.

See attached. Measure the voltage to ground of each point of interest.

U8500 is a load switch. Fancy name for a solid state relay and is used to power the LCD display. If you are not measuring a voltage to power the display / camera then the wiring that was applied should be reviewed and also the linked regulators.

Confirm that U8500 is being powered; being enabled. Post each measurement.

[Instafixx]

Re: Macbook 820-00923

Switch the (first) digital meter to the lower 200 ohm scale and measure again. The resistance looks ok for the CPU.

See attached. Measure the voltage to ground of each point of interest.

U8500 is a load switch. Fancy name for a solid state relay and is used to power the LCD display. If you are not measuring a voltage to power the display / camera then the wiring that was applied should be reviewed and also the linked regulators.

Confirm that U8500 is being powered; being enabled. Post each measurement.

The voltage at all points of U8500 is 0.
Since the area is a bit cramped hence i checked corresponding points on other area of the board for the same line. Its 0V.

The amp meter shows that the board is pulling 19.7V.

(Nothing is connected to the board except the charger.)


Setting the resistance to 200 i am getting 5.1 ohms at C10G1.

[mon2]

Re: Macbook 820-00923

After allowing for a normal boot up of the logic board, does the caps key LED toggle ? This will confirm that the logic board is booting.

[Instafixx]

Re: Macbook 820-00923

After allowing for a normal boot up of the logic board, does the caps key LED toggle ? This will confirm that the logic board is booting.

No, it doesnt toggle.
The Touchbar is inactive.
The trackpad works though.
Removing the trackpad cable also gives us a max fan spin (which it should).

[mon2]

Re: Macbook 820-00923

If you are drawing 20V, this means the CD3215s are working.

Check the following list of power rails:

https://www.logi.wiki/index.php/Power_Rail_List#A1706

Update:

Measure the voltage of L7660 to ground.

See attached - does the board turn ON/OFF with the button presses?

If yes, measure PM_PWRBTN_L voltage to ground as you press the same button(s). What voltage do you measure?

[Instafixx]

Re: Macbook 820-00923

If you are drawing 20V, this means the CD3215s are working.

Check the following list of power rails:

https://www.logi.wiki/index.php/Power_Rail_List#A1706

PPBUS_G3H
PPBUS_HS_CPU
PPBUS_HS_OTH5V
PPBUS_HS_OTH3V3
PPBUS_S4_HS_TPAD

ALL AT 13.03V TO 13.5V

PP3V3_G3H
PP3V3_G3H_SMC_ISNS

ALL AT 3.4V

PP3V0_G3H
AT 3.08V

PPVCC_S0_CPU
PPVCCSA_S0_CPU
PPVCCGT_S0_CPU

AT 0 VOLTS

IMVP RAILS AT 0.


PPVCCIO_S0_CPU

ALSO AT 0 VOLTS

CPU VCCIO Rails AT 0


PPVCCEDRAM_S0_CPU
ALSO AT 0 VOLTS

CPU EDRAM Rails AT 0



PPVCCPRIMCORE_SUS_PCH

IS AT 1V

PP0V6_S0_DDRVTT
PP0V6_S3_MEM_VREFDQ_A
PP0V6_S3_MEM_VREFCA_A
PP0V6_S3_MEM_VREFDQ_B
PP0V6_S3_MEM_VREFCA_A

ALL AT 0 VOLTS.

0V6 Rails AT 0

PP1V8_SUS
PP1V8_S4
PP1V8_S3
PP1V8_S3_MEM
PP1V8_S0

ALL AT 1.8 VOLTS

PP1V0_SUS
PP1V0_SUS
PP1V0_SUS
PP1V0_SUS

ALL AT 1V.

PP5V_S5 IS AT 5V
PP5V_S4 IS AT 5V
PP5V_S4SW IS AT 0V
PP5V_S4SW_ISNS IS AT 0V
PP5V_S0 IS AT 5V
PP5V_S0_KBD IS AT 5V

5V RAILS PARTIALLY MISSING

PP3V3_S5 is at 3.3V
PP3V3_SUS is at 3V
PP3V3_S4 is at 3.3V
PP3V3_TBT_X_S0 is at 3.3v
PP3V3_TBT_T_S0 is at 3.3V
PP3V3_S4_BT is at 3.3V
PP3V3_S4_TPAD is at 3.3V
PP3V3_S4SW_SNS is at 0V
PP3V3_S5_SSD_LB is at 3.3V
PP3V3_S5_SSD is at 3.3 V
PP3V3_S4_MESA is at 3.3V
PP3V3_2V7_NAND_VCC is at 2.7V

3v3 Rails are partially missing

PP3V3_S5_T139 is at 3.3V
PP3V3_S4_SOC_PMU is at 3.3V

T208 rails are ok.

I am bit worried now as the CPU rails are 0. I hope this is recoverable.

Voltage to Ground at L7660 Pin #1 is 3.3V and Pin#2 is 19.06V.

No the board doesnt turn on/off with the button pressed.

[mon2]

Re: Macbook 820-00923

What is the voltage to ground of SMC_SENSOR_PWR_EN ?

Review u8213.

[piernov]

Re: Macbook 820-00923

there was no voltage at
PP5V_S0

PP5V_S0 IS AT 5V

?

[Instafixx]

Re: Macbook 820-00923

?

Hi Piernov,
I didnt notice this. Thanks for pointing out. I will get back on this tomorrow. The rail voltage was checked at 2 different points i guess thats why the different voltages.
Will update tomorrow.

[Instafixx]

Re: Macbook 820-00923

What is the voltage to ground of SMC_SENSOR_PWR_EN ?

Review u8213.

SMC_SENSOR_PWR_EN at U8213 Pin#2 is 3.39V.

Pin#5/6 and Pin#7 is Missing.

[Instafixx]

Re: Macbook 820-00923

?

There is Voltage at PP5V_S0 and PP5V_S0_ALSCAM_F.

Maybe the initial reading was wrong.

[Instafixx]

Re: Macbook 820-00923

?

What can be the issue ? Please help. @piernov @mon2

[mon2]

Re: Macbook 820-00923

What is the voltage on pin # 1 of U8213 ?

Confirm each of the voltages on U8213.

If this part is being powered AND being ENABLED, then output should be present.

Either this load switch is defective OR the output rail is being shorted.

Remove all power -> meter in resistance mode and check the output pin # 5 to ground.

What is the resistance reading of PP5V_S4SW to ground ?

[piernov]

Re: Macbook 820-00923

Pp1v2_s3

[Instafixx]

Re: Macbook 820-00923

What is the voltage on pin # 1 of U8213 ?

Confirm each of the voltages on U8213.

If this part is being powered AND being ENABLED, then output should be present.

Either this load switch is defective OR the output rail is being shorted.

Remove all power -> meter in resistance mode and check the output pin # 5 to ground.

What is the resistance reading of PP5V_S4SW to ground ?

U8213

Voltages

Pin# 1 5.13V
Pin# 2 3.38V
Pin#3/4 5.13V
Pin#5/6 0.09V
Pin#7 0.09V
Pin# 8 GND


Resistance (Omega Mode)
Pin # 5 is 5.4.

[Instafixx]

Re: Macbook 820-00923

Pp1v2_s3

What about this?

[mon2]

Re: Macbook 820-00923

To me, U8213 is defective and should be replaced. This is a load switch that is being enabled but the voltage is not present at the output pin # 5.