820-02100 - Liquid Damaged. 5V 0.04~0.16A No Power.

[ronaldo]

The Mac is liquid damaged. Keyboard and probably screen. No power.
On the LB there was liquid on the U5700, UT00, UF750, around the UR630. There was some liquid coming out from under the shield opposite the CPU.
The customer took it to me 30 minutes after the liquid accident.
On the amp meter it stays on 5V 0.045A for 21 secs after it keeps cycling to 0.160A
No short or wrong reading on the coils or around the affected area.

All the lines that is cycling at the start it's 0V and after 21 secs it starts cycling.
On battery the PPBUS_AON is 12.81V

PPBUS_AON - 12.31V
PP3V8_AON = 3.8
PP5V_S2 = Cycling
PP1V8_S2SW = Cycling
PP1V8_S2 = Cycling
PP1V2_AWAKE = Cycling
PP1V2_S2 = Cycling
PP0V95_S2SW_VDD2L = Cycling
PP0V855_S2SW_VDDCIO = 0V
PPVDD_ECPU_AWAKE = 0V
PPVDD_DISP_AWAKESW = 0V
PPVDD_AVEMSR_AWAKESW = 0V

P2V5_NAND0_SW = 0V
PPDCIN_AON_CHGR_R = 5.14v
PPVIN_P1V8VDDH_DRMOS = 12.31V
P1V8VDDH_SW2 = 0V

All the voltages above has been measured on USB-C port.
On the MagSafe 3 there is no light at all.
Thanks in advance for any help.

 

[ronaldo]

PPDCIN_AON_CHGR_R |P_IN 5.13V
CHGR_AUX_DET 0.86V
VDDA 4.6V
VDDP 4.6V
EN_MVR 4.5V ~ 4.7V
AUX_OK 1.78V
CHGR_AMON 0V
CHGR_BMON 0V

 

[ronaldo]

Battery charging / PPBUS IC RAA489900 - Replaced and same results.

 

[2informaticos]

"CHGR_AUX_DET 0.86V"
It should be 1.25V aprox, with 5V input.
Check R5215/6, ohm values.
Also check AUX_DET_SHORT voltage.

What about diode mode readings on SSD power lines?

 

[ronaldo]

R5215
Pin 1 - CHGR_AUX_DET - 132Kohm / Diode 0.470 - On a working board according to FlexBV it should be 0.549
Pin 2 - PPDCIN_AON_CHGR - 70Kohm / Diode 0.620

AUX_DET_SHORT - 0V

P0V9_LX0_NAND0 - 0.320
P1V2_LX0_NAND0 - 0.309
PP2V5_NAND0 - 0.307

 

[ronaldo]

R5215 is supposed to be 750k and was 450K
R5216 is supposed to be 255k and was 149K
After replacing both the CHGR_AUX_DET is now 1.28V

CHGR_AUX_DET still 0.466 in diode mode.

 

[ronaldo]

Q5216 replaced and CHGR_AUX_DET is 0.545

 

[2informaticos]

MLB still cycling?

Check diode mode to ground on all power rails which don't get voltage at all.

 

[ronaldo]

Yes, still cycling.

PPVDD_DISP_AWAKESW - 0.160 / FlexBV-0.210
All the lines are matching a working LB apart of this above.

 

[2informaticos]

Something else has been affected by liquid.
Possibly accumulated crap underneath BGA chips.

Did you test the board alone on the desk?
Check if U8100 and U7700 LDOs cycling too.

 

[ronaldo]

Yes, I'm actually testing it alone.
But even with the battery is same.

I found P5VS2TPS_PGOOD wrong reading on diode mode.
Q6070 relaced and now it's correct, but still same.

 

[ronaldo]

That's crazy. I found R8170 OL and is supposed be 200K.
Resistor replaced and still same.

 

[2informaticos]

Not sure what is exact R8170 value, but pretty sure not 200K.
Read the notes on the bottom of page 41.

Be sure PMU_VDDHI stays above 1.5V; if drops, MPMU restarts power on sequence.