820-00928-04 No power

MarcinRdm

Member
Hello
I am new to this forum. My name is Marcin and i work a electric repair shop in Poland. I am new to MacBook repairs and have lot of knowledge to complete. As for now i have a MacBook pro model A1707 820-00928-04 that wont start.
I can see under my microscope that someone soldered the U3100.
I put the chip down again. I know I have a problem with the PP1V1 line nad PPBUS_G3H (0,017v, 0,402 diode-mode) but I don't know which chargers to replace . Can you please guide me were to check

I checked
Supply/LDO Rails - Diode Tests:

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

PP20V_USBC 5.2V only where the charger is connected

I think I need to replace the UB400. I'm right ?
 
Last edited:

2informaticos

Administrator
Staff member
First of all, welcome to the forum!

1V1_LDO must appear only at the powered port.
Looks like the problem is on UB400 area.

BTW, 3V3_G3H is the same power rail over entire board.
Do not waste time measuring it on different points.
 

MarcinRdm

Member
Thanks for the advice. Reballing UB400 didn't help. I measured the voltage on the pin CB404 (without capacitor). I'm ordering a new CD3215C.
 

MarcinRdm

Member
I now. UB400 is the only one with no power when the charger is connected. I noticed that the voltage does not restart in one usb-c input but still no 1.1v
 
Last edited:

MarcinRdm

Member
no, I didn't:
PP1V1_UPC_TA_LDO_BMC: on CB404
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
Not restarting on bottom usb-c on the left side (UB400)
Should i replace TBT ROM, UB090 for UB400 ??
 
Last edited:

2informaticos

Administrator
Staff member
Usually restarts means the problem is not on the corresponding port.
Board tries to start and SMC detects some error and blcok the power on sequence.
But you should first locate the problem on the port with fixed 5V.

Remove USB-C connector from the shell (for corresponding port) and inspect the pins.
Compare diode mode readings around UB400 and another working CD3215 area.
Pay atention to CC1/2 pins and input fuse.
 

MarcinRdm

Member
CC1/2 is the same everywhere around CD3215 (UB300 UB400 U3100 U3200)
USBC_XB_CC1 diode-mode: 0,580
USBC_XB_CC2 diode-mode: 0,580
USBC_XA_CC1 diode-mode: 0,584
USBC_XA_CC2 diode-mode: 0,579
USBC_TB_CC1 diode-mode: 0,572
USBC_TB_CC2 diode-mode: 0,580
USBC_TA_CC1 diode-mode: 0,570
USBC_TA_CC2 diode-mode: 0,574
 

2informaticos

Administrator
Staff member
Values look good, but something else should be bad around UB400; if that is the fixed 5V port.

In theory, UB090 should be good, as it is used by UB300 to boot.
UB400 boots later from UB300.
But you can try to change it, or reflash, just in case.
Be sure to make a backup of its content.

Check all resistors around UB400 and from page 103.
 

MarcinRdm

Member
Thank you for your answer.
Today I will reflash UB090
I will check the resistors later. Im using the scheme 820-00281 if someone has exactly 820-00928-04 ?
 
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