Macbook 820-00923

[Instafixx]

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.

But there is no component here. Its like this. See Attachment

How to replace this??

[mon2]

Re: Macbook 820-00923

Let me review it once at the office.

[Instafixx]

Re: Macbook 820-00923

Let me review it once at the office.

Okay. Eagerly waiting for your reply. Thanks a ton.

[mon2]

Re: Macbook 820-00923

Can you confirm if the markings of your board = 820-00923 ?

From the schematic, they look as though the parts should be there but given that this laptop was working before, there must be an alternative bill of materials.

[Instafixx]

Re: Macbook 820-00923

Can you confirm if the markings of your board = 820-00923 ?

From the schematic, they look as though the parts should be there but given that this laptop was working before, there must be an alternative bill of materials.

Yes it is 820-00923.
I checked with other dead boards as well. This particular components are not there.

[piernov]

Re: Macbook 820-00923

What about this?

You haven't posted measurements.

From the schematic, they look as though the parts should be there but given that this laptop was working before, there must be an alternative bill of materials.

LOADISNS BOM option is only populated on engineering boards as indicated by the BOM configuration.

[Instafixx]

Re: Macbook 820-00923

You haven't posted measurements.



LOADISNS BOM option is only populated on engineering boards as indicated by the BOM configuration.

Hi,
Getting 1.2V at Pin # 1 of C7907

[Instafixx]

Re: Macbook 820-00923

Can you confirm if the markings of your board = 820-00923 ?

From the schematic, they look as though the parts should be there but given that this laptop was working before, there must be an alternative bill of materials.

Hi, Please help me out here.

[Instafixx]

Re: Macbook 820-00923

Hi I have an update.

Went ahead and did a reball of the U7800. Post that we have

PPVCC_S0_CPU all at 1.05V
PPVCCSA_S0_CPU at 1.05V
PPVCCGT_S0_CPU at 0V


PPVCCIO_S0_CPU at 0.95V

PP3V3_S4SW_SNS is at 3.3V

PP0V6_S0_DDRVTT
PP0V6_S3_MEM_VREFDQ_A
PP0V6_S3_MEM_VREFCA_A
PP0V6_S3_MEM_VREFDQ_B
PP0V6_S3_MEM_VREFCA_A

all 0.6V

so from the initial power rails now we have

PP5V_S4SW IS AT 0V
PP5V_S4SW_ISNS IS AT 0V

PPVCCEDRAM_S0_CPU
ALSO AT 0 VOLTS


for the EDRAM Rail I think there are a few MosFETs which control that. Will be needing your help for that.

For the S4SW I am still confused as their are no components present in the board.

[mon2]

Re: Macbook 820-00923

Hi. From Louis' forums:

If U8213 is not factory installed
Then PP5V_S4SW is not required.

Can you check it?

[Instafixx]

Re: Macbook 820-00923

Hi. From Louis' forums:

If U8213 is not factory installed
Then PP5V_S4SW is not required.

Can you check it?

Its 100% confirmed that it is not factory installed

[Instafixx]

Re: Macbook 820-00923

Hi. From Louis' forums:

If U8213 is not factory installed
Then PP5V_S4SW is not required.

Can you check it?

What about the PPVCCEDRAM rail? There are MosFETS controlling it. Any help?

[mon2]

Re: Macbook 820-00923

What is the voltage to ground of

PLT_RST_L ?

all_sys_pwrgd ?

[mon2]

Re: Macbook 820-00923

Re: post #32

Review this thread:

https://boards.rossmanngroup.com/thr..._s0_cpu.41372/

[Instafixx]

Re: Macbook 820-00923

What is the voltage to ground of

PLT_RST_L ?

all_sys_pwrgd ?

PLT_RST_L is at 3.3V
ALL_SYS_PWRGD is at 3.2V

[Instafixx]

Re: Macbook 820-00923

PLT_RST_L is at 3.3V
ALL_SYS_PWRGD is at 3.2V

Hi Mon2,
So I have managed to arrange another working board for the same model. The voltages are the same as per my current boards readings.
( When checking the standalone board ).

But still it won't switch on.
I am guessing that the reflow U7800 solved something because the heating of the CPU has also decreased a lot back to normal levels. But the machine is still not switching on.

[mon2]

Re: Macbook 820-00923

Compare the resistance to ground of the cpu on both logic boards. Remove all power. Meter in resistance mode. Measure.

[Instafixx]

Re: Macbook 820-00923

Re: post #32

Review this thread:

https://boards.rossmanngroup.com/thr..._s0_cpu.41372/

Followed the Link and Checked the Critical 1 of 10 for U7800

PP1V8_S3 is at 0 Volts
PP3v3_S0 is at 0 Volts
PP1v8_S0 is at 0 Volts
P5vS4_PGOOD is at 0 Volts
PM_SLP_S3_L is at 0 Volts
P1V8SUS_PGOOD - Unable to check as it is below the IC.
PM_SLP_S4_L is at 0 Volts.
PM_SLP_S3_L is at 0 Volts.
CPUVR_PGOOD is at 0 Volts


Is the U7800 damaged?

Checked Voltage with standalone board with nothing connected only the charger.

[mon2]

Re: Macbook 820-00923

Remove all power.

Meter in diode mode.

Red meter probe, yes RED to ground.
Black meter probe to point to test.

Measure the diode mode reading of PP3V0_G3H.

Also see here:
https://boards.rossmanngroup.com/thr...-reason.59308/

[Instafixx]

Re: Macbook 820-00923

Remove all power.

Meter in diode mode.

Red meter probe, yes RED to ground.
Black meter probe to point to test.

Measure the diode mode reading of PP3V0_G3H.

Also see here:
https://boards.rossmanngroup.com/thr...-reason.59308/

What should be the reading there?