820-00928 20v, 0a

MarcinRdm

Member
No liquid damage, board in perfect condition. According to customer, this MacBook suddenly died on him.
PPBUS_G3H 12.59v
PP3V3_SUS = 3.3v
PM_BATLOW_L - 1.05v
PM_SLP_SUS_L - 3.31v
PM_DSW_PWRGD - 3.4v
PM_RSMRST_L 3.3v
PM_PWRBTN_L - 3,3v

UB300
CB300: 3V3_G3H: Diode-Mode: 0.331
3V3_G3H: 3.415V
Diode Test on LDO Rails:
PP3V3_UPC_TA_LDO: on CB308: 3.385v, diode-mode: 0,492
PP1V8_UPC_TA_LDOA: on CB306: 1.805v, diode-mode: 0,502
PP1V8_UPC_TA_LDOD: on CB305: 1.802v, diode-mode: 0,466
PP1V1_UPC_TA_LDO_BMC: na CB304: 1,124v only in one USB port, diode-mode: 0,483

UB400
CB400: 3V3_G3H: Diode-Mode: 0.331
3V3_G3H: 3.416V
Diode Test on LDO Rails:
PP3V3_UPC_TB_LDO: on CB408: 3.383v, diode-mode: 0,486
PP1V8_UPC_TB_LDOA: on CB406: 1.803v, diode-mode: 0,502
PP1V8_UPC_TB_LDOD: on CB405: 1.792v, diode-mode: 0,467
PP1V1_UPC_TA_LDO_BMC: na CB404: 0v always, diode-mode: 0,484

U3100
C3100: 3V3_G3H: Diode-Mode: 0.332
3V3_G3H: 3.415V
Diode Test on LDO Rails:
PP3V3_UPC_XA_LDO: on C3108: 3.383v, diode-mode: 0,486
PP1V8_UPC_XA_LDOA: on C3106: 1.815V, diode-mode: 0,504
PP1V8_UPC_XA_LDOD: on C3105: 1.799v, diode-mode: 0,469
PP1V1_UPC_XA_LDO_BMC: on C3104: 1.118 only in one USB port, , diode-mode: 0,486

U3200
C3200: 3V3_G3H: Diode-Mode: 0.331
3V3_G3H: 3.414V
Diode Test on LDO Rails:
PP3V3_UPC_XB_LDO: on C3208: 3.377v, diode-mode: 0,489
PP1V8_UPC_XB_LDOA: on C3206: 1.802v, diode-mode: 0,502
PP1V8_UPC_XB_LDOD: on C3205: 1.798V, diode-mode: 0,469
PP1V1_UPC_XB_LDO_BMC: on C3204: 1.120 only in one USB port,, diode-mode: 0,485
 
Last edited:

2informaticos

Administrator
Staff member
"PM_BATLOW_L - 1.05v"
There is a problem; signal is pulled-up to 3V3_S5 (R1212).
Test again using 87/96W charger.

USB-C areas should be OK, if you get 20V on all ports.
 

2informaticos

Administrator
Staff member
Does it charges the battery?
Try to start with both charger and battery connected.
Also try SMC bypass.
 

MarcinRdm

Member
I tried . Does not charge the battery.
SMC bypass without batteries - Holding down the power button the board Just stays at 5v until I let go to 20v
 

MarcinRdm

Member
I tried again. After the bypaaas it suddenly booted up and started charging. For a while. Now it's not booting up again.
 

2informaticos

Administrator
Staff member
Try to turn it on with known good battery, which holds some charge.

In SMC bypass, battery should not charge and fans spin to max.
 

MarcinRdm

Member
Now charging the battery. In my case, the fans did not spin. Maybe I'm doing a SMC reset wrong. I did this without a battery connected.
 

MarcinRdm

Member
Sorry, I meant the bypass all along.
When I release the power button, windmills don't move . Momentarily 3.3v on PM_BATLOW_L.
 
Last edited:

MarcinRdm

Member
With both battery and charger connected is steady voltage 1.05v.
Without batteries momentarily 3.3v on PM_BATLOW_L after a while 1.05v.
With battery alone is 1.05v when I press the power button.
Starts when I connect pin 1 to pin 2 - R1212
I replaced R1212 and it started up for a while
 
Last edited:

2informaticos

Administrator
Staff member
Looks like SMC problem; is the one which controls PM_BATLOW_L.
You can try reballing it; may need to change it.

Forcing the signal with 1k in place of R1212, is other option.
Give it a try.
 

2informaticos

Administrator
Staff member
The SMC internal open-drain MOSFET, which controls PM_BATLOW_L, can get burnt.
Try to force the signal with 100 ohms, instead of 1K.
 
Top