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[Solved, bad PMIC] 820-00928, 20V @ 0.0178A. No water damage

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down1nit

Member
Customer says it just won't turn on. I tried another battery, and then another whole top case with new battery already installed. No change. 5v negotiates to 20v after about 10 seconds, .468A drops to .0178A after 20v reached. Dual mosfet gates never told to open by U7000

Inspection, pretty thoroughly, no obvious damage, no obvious holes in resistors, clean overall.

Rails i've tested:

PPBUS_G3H : .77v (no shorts to CPU/GPU inductors, no shorts to any major inductors)
PP3V3_G3H: 3.4
PPVCCIO_S0 and PPVCC_S0_CPU : 0v (obv but just to show no short and cpu stays cold)
PP3v3_S5: 0
PP3v3_S5_T139: 0
PP5V_S5: 1.05v
PP3V3_SUS: .163v
PP1V2_S5_SMC_VDDC: 1.2v
PP1V_S5_PCH_DCPDSW: 0
SMC_RST_L: 3.4v
HPWR_EN_L: 3.37v
TBA_VDDA: 5v
TBA_VDDP: 5v
PPDCIN_G3H: 20v
PPVBAT_G3H_CHGR_R: .769v
PM_EN_P3V3_G3H: 5v
SMC_BC_AC_OK: 3.4v


Replaced U7000 with one from store dot rossmanngroup dot com as I'm used to doing automatically, no change. Did a bunch of diode measurements using a working 00281 (so far only around u7000, gonna do the rest of page 64 later). The only differences are small, one is to pp3v3_g3h which measured at 3.4v while plugged in, another difference was on TBA_BOOT1_RC, it measured lower drop in diode mode unplugged. Checked basically every resistor around U7000, only found the 750K slightly out of spec, replaced, no change.

I've yet to compare resistances/diode to ground on inductors, or remove fuses and test.

25k PCH Clock present. That's all the things I know to check on these fucking boards. I could use some help, thanks.
 
2informaticos

2informaticos

Administrator
Staff member
Can you post diode mode (red probe connected to ground) at PPBUS_G3H?
Also post TBA_AUX_DET and SMC_BC_ACOK levels.

Remove F7000/1 and check voltage at C7050.
Be sure C7030/40 are good.
 
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down1nit

Member
Diode mode, red on ground, PPBUS @ F7000 pin 2: .409
TBA_AUX_DET: 5.01v
SMC_BC_ACOK 3.4v

Removed Fuses, Plugged in adapter, C7050 .244v

C7030/40: Both caps measure 110nf, after removing from board.

Diode at REMOVED Fuses Pin 2: .398. Pin 1: .505
 
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down1nit

Member
Did it again. Fresh 9239 from sealed package. Same exact result. :( Do these have SMC issues or BIOS issues?

Would it be any use to remove the U7000 and provide diode measurements?
 
2informaticos

2informaticos

Administrator
Staff member
ISL9239 requires good communication with SMC.
Is weird, that SMC works partially at least, switching USB-C input to 20V.
You should change it, just in case.

First check voltage and diode mode on SCL/SDA lines of battery bus.
 
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down1nit

Member
Yeah. I'm gonna try that actually. Thanks.

It does actually take quite some time to get to 20v. Like 20 - 30 seconds, like it was a 2014 air going through 2 restarts before starting up
 
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down1nit

Member
HA! OK so SCL on J6951 (battery data cable) was low in diode mode. Replaced TVS diode D6950. Now it negotiates 20v at a normal speed, instead of taking 10 seconds or more. Board Takes .320 mA now according to ammeter. Same with a battery.

I have one 00928 SMC if needed, don't suppose a 00281 will work though?
 
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down1nit

Member
Thanks, yes PPBUS is present at 12.60. I know that a 00281 and 00928 aren't compatible SMC wise, it was wishful thinking is all.

I'll start going down the lines again to check I haven't lost anything else now.
 
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down1nit

Member
DCIN: 20V
PPBUS/PPVBAT_G3H_CHGR_R: 12.6
3V3_G3H: 3.4
3V3_S4: 0
3V3_S5: 3.3
5V_S5: 5
5V_S4: 0
3V3_SUS: 3.3
1V2_S5_SMC_VDDC: 1.2
SMC_RST_L: 3.4
HPWR_EN_L: 3.38
1V_S5_PCH_BLAHBLAH: 1.0
TBA_VDDA/P: 5
PM_EN_P3V3_G3H: 5
SMC_BC_ACOK: 3.4
PLT_RST_L: 0
PM_SLP_S5_L: 0
PM_SLP_S4_L: 0
PM_SLP_SUS_L: 0.98
SMC_PM_G2_EN: 3.4
PP3V3_PMICLDO: 3.3
ALL_SYS_PWRGD: 0
S5_PWRGD: 3.3
PM_RSMRST_L: 0.026
SMC_PCH_SUSACK_L: 0
PM_PCH_SYS_PWROK: 0
PM_PCH_PWROK: 0
PM_RSMRST_L: 0.02
SMC_PCH_SUSWARN_L: 0
PM_PWRBTN_L: 3.3
SSD_SR_EN_L: 0.03
PM_BATLOW_L: 3.3
SYSCLK_CLK32K_PCH: 32.9 kHz
PCH_INTRUDER_L: 2.84
PCH_SRTCRST_L: 3.09
RTC_RESET_L: 3.08


I'm sure this is way too much, and possibly missing something critical. I want to be thorough for fellow techs who find this.
Looks like i'm not getting s4 enable? Who's responsible for that?
 
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down1nit

Member
It got better looks like. Am I wrong in not adding PP beforehand?

Edit: when i reread this it looks like i'm being a jerk, i'm not. Maybe I measured at a different point before? Is .98 low enough to assert pm_slp_sus_l?
 
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down1nit

Member
PM_SLP_SUS_L shows .003 in diode mode. 10 ohms black on ground in resistance mode.

U8200 removed = same. r1237 @ 100k out of circuit

So PCH or PMIC? PMIC on the data lines that dead TVS diode was on.
 
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down1nit

Member
Thank you again 2. It was thankfully the PMIC. Had to reball a donor like 3 times because I've never been good at doing the real big chips, and it likes to fly off.

I learned to control my airflow, change to a larger nozzle, and move my scope so i can blow straight down onto the chip.

Getting boot current now!
 
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