820-02773 MacBook Pro 13'' M2 A2338 get 5V 0A does not boot

Hello out there.

I purchased this mac MacBook Pro 13'' M2 chip, model A2338, logic board number 820-02773 as partially working. Seller give me an apple report saying: "Liquid spill on trackpad flat, BMU battery flat and logic board. Macbook starts only when connected to DC IN and show intermittent shoutdown".

Now ,that I got, it is does not start at all, usb Amp mether shows 5V 0A on both usb-c. Connecting to the transformer adapter side (not logic board side) I can detect 5.237V and 0.034A.

Tearing down the logic board I can confirm there was liquid spill on the battery connector area and the battery flat. Liquid spill also on the trackpad connector and small amount on the antenna wifi connectors.

The back side of the board is pretty clean, no sings of corrosion or cleaning.

The fact is that this moderboard was already cleaned from moisture.

no components it's getting hot when plugged in.

Upon cheking, no low resistance found at each inductor / coil on the board.

PPBUS_AON
1 PPBUS_AON 12.3V
2 PPVIN_LCDBKLT_F 12.3V

PP3v8_AON
L5800
1 P3V8AON_VSW1 3.78V
2 PP3V8AON_PH1 3.78V


PPDCIN_AON_CHGR_R 5V on both ports

LDO outputs

PP3V3_UPC1_LDO 3.44V
PP1V5_UPC1_LDO_CORE 1.58V

PP3V3_UPC0_LDO 3.44V
PP1V5_UPC0_LDO_CORE 1.58V

CD3217 support voltages

CC270
PP5V_S2 0V

RG2A0
1 PP3V3_S2_LDO 0V
2 PP3V3_UF790 0.34V

PP3V3_S2_USBLS1_ISNS 0V
PP3V3_S2_WLBT_ISNS 0V
PP1V25_S2 0V

RC714
P3V3S2_PWR_EN 0V
P3V3S2_EN 0V

PPBUS_AON_3V3S2_VIN_ISNS 12.30V

LC260
1 P5VS2TPS_PHASE 0V
2 PP5V_S2 0V


P5VS2_PWR_EN_RC 0V


PP1V5_LDOINT_MPMU 1.48V

PP17V0_LDOIN 3.30V.


resistance to ground of PP3v3_S2.
CC717
pin1 PP3v3_S2 35 ( 2000K scale on multimeter) ohms
pin0 gnd 0 ohms

Upon cheking, no low resistance found at each inductor / coil on the board. Also attached in photos diode mode readings. Mine in red, black one as reference.


Sorry for boing noob as hell, I hope to learn something here.

I would be glad if somenone more skilled that me will help me troubleshotting this Mac to have it finally working. That would be really appreciated.

Did you measure diode mode with red probe connected to ground?

Check MPMU LDOs at page 38.
Do you get all voltages there?

2informaticos said:

Did you measure diode mode with red probe connected to ground?

Click to expand...

Exaclty

Not getting all voltages in MPMU LDOs:

VDD LDO 3/8/14/20

C8300
1 PPVDD_LDO20_14_8_3 0V

LDO 2 DECOUPLING

C8320
1 PP1V8_AON 0.18V

LDO 9 DECOUPLING

C8310
1 PP1V8_AON_MPMU 1.80V

LDO 11 DECOUPLING

C83B6
1 PP0V855_S2SW_CIO 0V

LDO INT DECOUPLING

C8380
1 PP1V5_LDOINT_MPMU 1.49V

VDD LDO 11

C83B0
1 PPVDD_S2SW_VDD2H 0V

LDO 7 DECOUPLING

C8330
1 PP3V3_S2_LDO 0V

LDO 9B DECOUPLING

C8340
1 PP1V2_AON_MPMU 1.20V

LDO 13 DECOUPLING

C83D0
1 PP3V3_S2SW_SNS 0V

LDO 8 DECOUPLING

C8360
1 PP1V2_AWAKE_PLL 0V

LDO 10 DECOUPLING

C83A0
1 PP3V3_AON 0.34V (this is strange, when i touch this pin i can hear a cliking sound coming from the board, on the other side i think, only when i touch with multimeter tip)

LDO 20 DECOUPLING

C8350
1 PP1V2_S2_CIO 0V


C81AE
1 PP3V8_AON_MPMU_ISNS_VIN 3.77

What schematic are you using?
U8100 is BGA chip.


BTW, don't waste time checking, or writing down ground pins.

I'm using this BVR + schem. https://files.fm/u/zdwvagcwj . Anyway, the schematics are the same.

Do I need to check LDO voltages direclty on U8100?

Find convenient test points on adjacent components.
Do not check the rails marked as "NC_"

U8100 LDO OUTPUT

PP1V8_AON 0.18V

PP3V3_S2_LDO 0V

PP1V2_AWAKE_PLL 0V

PP1V8_AON_MPMU 1.80V

PP1V2_AON_MPMU 1.20V

PP3V3_AON 0.35V

PP0V855_S2SW_CIO 0V

PP3V3_S2SW_SNS 0V

PP1V2_S2_CIO 0V

PP1V5_LDOINT_MPMU 1.49V


U8100 LDO INPUT

PP3V8_AON_MPMU_ISNS_VIN 3.77V

PPVDD_LDO20_14_8_3 0V

PPVDD_S2SW_VDD2H 0V

That's done correctly?

Possibly bad U8100...

2informaticos said:

Possibly bad U8100...

Click to expand...

There is anything I can do to confirm diagnosis? Anyway I have a donor A2338 M1 logic board, could U8100 be swapped?
Really thank you for support provided to me. Hope to solve and get this macbook back to work.

Dificult to confirm.
Many of your readings are higher than refference board.
You can't expect exact same readings, but some of them are too high.

Worth to try heating U7700/8100 with quality flux first.
Just in case of accumularted crap underneath.
Even M2 area may be affected.

Right. I'll try to heating U7700/8100 with quality flux, even if I didn't notice any moisture nearby it.
I would like also let you know that prior to post all my readings U5700 buck converter IC, Q5800, Q5820, Q5840 mosfets has been replaced, taken from M1 820-02020 logic. This was done as I accidentally shorted U5700 while taking readings. I also replaced UD600 becouse it has spill on it

2informaticos said:

heating U7700/8100 with quality flux first

Click to expand...

Done, but no progress at all. Same as before. No crap underneath seen.

Then I had put logic in ultrasonic cleaner and now I did not have voltage on PP3v8_AON.

2informaticos said:

Many of your readings are higher than refference board

Click to expand...

Are you referring to diode mode readings? Probably my multimeter is not good quality one.

Check for knocked off components, or broken trace.
This can happen in ultrasonic process, especially if no sweep function used.

Checked for knocked off components and broken trace, no one missing.

Now PP3v8_AON is back, 3.78V

Check U7700/8100 LDOs...

2informaticos said:

Check U7700/8100 LDOs...

Click to expand...

here it is:

U8100

PP3V8_AON_MPMU_ISNS_VIN
CY1M3 3.77V

PPVDD_LDO20_14_8_3
C8300 0V DIODIE MODE 269

PPVDD_S2SW_VDD2H
C83B1 0V DIODE MODE 36

PP1V8_AON
R8620 1.79V

PP3V3_S2_LDO
C8331 0V DIODE MODE 1.25 (20k multimeter scale)


PP1V2_AWAKE_PLL
C8360 0V DIODE MODE 358

PP1V8_AON_MPMU
C84A0 1.79V

PP1V2_AON_MPMU
C8341 1.19V

PP3V3_AON
C83A0 0.33V (CLIKING SOUND WHEN MEASURING) DIODE MODE 0.84 (20K SCALE MULTIMETER)

PP0V855_S2SW_CIO
C83B5 0V DIODE MODE 0.54 (20K SCALE MULTIMETER)

PP3V3_S2SW_SNS
C83D0 0V DIODE MODE 488

PP1V2_S2_CIO
C8350 0V DIODE MODE 01.19 (20K SCALE MULTIMETER)


PP1V5_LDOINT_MPMU
C8380 1.50V





U7700





PP3V8_AON_SPMU_ISNS_VIN
CY1S5 1.77V

PP1V25_S2
RT311 0V DIODE MODE 246

PP0V88_S1
C77C1 0V DIODE MODE 01.27 (20K SCALE MULTIMETER)


PP0V72_S2_VDD_LOW
C7840 0V DIODE MODE 256

PP1V8_AON_SPMU
C7891 1.80V

PP1V2_AON_SPMU
C78A0 1.20V

PP0V8_S1_VDD_FIXED
C78C0 0V DIODE MODE 0.35 (20K SCALE MULTIMETER)


PP1V5_LDOINT_SPMU
C7810 1.50V


is that normal in PP3V3_AON VLDO10 U8100 I got 0.33v? And hear that cliking sound?

"PP3V8_AON_SPMU_ISNS_VIN
CY1S5 1.77V"
Are you sure?
Check RD580 voltages...

2informaticos said:

PP3V8_AON_SPMU_ISNS_VIN
CY1S5 1.77V"
Are you sure?
Check RD580 voltages...

Click to expand...

My bad,

PP3V8_AON_SPMU_ISNS_VIN
CY1S5 3.77V

RD580 voltages
TPE018
TP_ISNS_SPMUHS_N ISNS_SPMUHS_N 3.77V
TPE017
TP_ISNS_SPMUHS_P ISNS_SPMUHS_P 3.77V
CY1SB
PP3V8_AON_SPMU_ISNS_VIN 3.77V
CY247
PP3V8_AON 3.77V

You may have a problem with U8100.
Try changing it...

BTW, do not quote an entire post, which appears few centimetrs above.
Write directly into reply box, instead of clicking Reply button.
Please, maintain forum aesthetic.

Ok, I'll do!
IF I remember correctly, I read in somenone other post that Macbook M1 U8100 and M2 one are different. At the moment, I don’t have a donor board to take it, and I don’t know if I’ll ever have one.

As I mentioned, U5700, Q5800, Q5820, Q5840 have been replaced, taken from the M1 820-02020 logic, could this somehow affect it?”