820-00928 stuck on 5v

[2informaticos]

There should be other components affected by corrosion.
Remove F7000/1 and check C7050 voltage.
Check ohm resistance over C7020/23.
Also check R/C/Q7030/40.

 

[2informaticos]

Post voltage and diode mode to ground at SMBUS_SMC_5_G3H_SCL /SDA lines.
Check PPBUS_G3H and 3V3_G3H with battery connected; w/ and w/o charger present.
Don't forget to connect battery data cable.

 

[tcampbell34]

SMBUS_SMC_G3_SCL and SMBUS_SMC_G3_SDA are both 3.3v and fluctuates down to about 2.6v every couple of seconds. Both measure 0.441 in diode mode, which matches another board I have that gets 20v. PPBUS is like 5mv with or without the battery connected and PP3V3_G3H is 3.4v with the battery and charger, but 1.4mv with just the battery. I don't think the battery is charged though so that would be why PP3V3_G3H is missing on battery alone.

 

[2informaticos]

Did you test the board alone on the desk?
No trackpad, LCD, nor other cable connected.

 

[tcampbell34]

Yes just the board alone on the desk with charger connected.

 

[2informaticos]

Can you charge the battery with the other board, which switch to 20V?
This may help to diagnose if the problem is on USB-C side, or other side.

 

[tcampbell34]

Yea I was able to charge the battery using another board with a dead CPU. Now when I connect this board to the charged battery and connect the charger, I get 20v 0.00a, still does not turn on. PPBUS is 12.7v and PP3v3_g3h is 3.4v with both the battery and charger connected and its the same thing with just the battery.

 

[2informaticos]

If USB-C ports switch to 20V with battery connected, means SMC can communicate properly with CD3215 chips.
You can have a problem with U7000, or its surrounding components.
Check SMC_BC_ACOK and A/BMON.

 

[tcampbell34]

SMC_BC_ACOK is 3.4v but AMON and BMON are 0v both with and without the battery connected. I replaced U7000 again, but still the same

 

[tcampbell34]

SMC_DCIN_VSENSE seems low at only 0.682v. R5498 and R5499 are good. I have 5.2v at pin 1 of R5498 and then 0.682v on pin 2.

 

[2informaticos]

SMC_DCIN_VSENSE is correct, as you don't get 20V input voltage yet.
A/BMON are also good, because the board doesn't start.

Check power on signals with charger plus battery connected.

 

[tcampbell34]

SMC_BC_ACOK is actually 3.4v only when just the charger is connected and the board is stuck at 5v. When the battery and charger are connected and its taking 20v, that signal is 0v. I checked the below signals with just the charger connected and then again with both charger and battery connected.

Signal	Battery + Charger (20v)	Charger only (5v)
SMC_USBC_INT_L	0	0
SMC_CHGR_INT_L	3.4	0
SMC_PMIC_INT_L	3.4	3.3
SMC_BC_ACOK	0	3.4
SMC_ADAPTER_EN	0	0
S5_PWRGD	0	0
PM_BATLOW_L	0	78.7mv
PM_DSW_PWRGD	0	0
SMC_RESET_L	3.4	3.4
PM_RSMRST_L	0	360mv

 

[tcampbell34]

I do have 12.6v with the battery connected on PPBUS, but the board still won't start.

 

[2informaticos]

Then check U7800 basic signals with battery connected.
Also check PCH's RTC signals.

 

[tcampbell34]

PP3V3_S5 - 0v
PP5V_S5 - 0v
PP5V_S4 - 0v
PP3V0_G3H - 3.09v
PM_DSW_PWRGD - 0v
PCH_INTRUDER_L - 2.8v
RTC_RESET_L - 3.08v
PCH_SRTCRST_L - 3.4v
PPDCPRTC_PCH - 1.123v
SMC_PMIC_INT_L - 3.4v
PM_SLP_SUS_L - 0v
LPC_PWRDWN_L - 26.5mv
PM_RSMRST_L - 0v
PM_PCH_PWROK - 0v
PM_PCH_SYS_PWROK - 0v
PMIC_SHUTDOWN_L - 3.2v

 

[2informaticos]

Check LDO and VREF rails at U7800 (7 OF 10).
Also check SMC_ONOFF_L and SMC_RESET_L levels.
Remember to keep battery connected.

 

[tcampbell34]

PP3V3_PMICLDO 3.3
PP5V_PMICLDO 5.0
PPBUS_PMIC 11.31
PP1V25_PMICVREF 1.25
SMC_ONOFF_L 3.4
SMC_RESET_L 3.4