(Resolved) 820-00281-A only 5V, no 20V. Missing PPBUS_G3H

[joshAU]

Hi all.
I have an A1707 2016 macbook that is not turning on, either via battery or via genuine known good AC adapter.
No signs of liquid damage.
Missing PPBUS_G3H.

Suspecting U7000, but thought I'd get advice first.

Here's a list of what we've checked.

PPDCIN_G3H = 5.27v
PPBUS_G3H = 0.23v decreasing
PPBUS_G3H Diode mode to ground = 455
PP3V3_G3H = 0.05v decreasing
PP3V3_S5 = 0v

PM_EN_P3V3_G3H = 5.04v
TBA_AUX_DET = 1.3v
TBA_VDDA = 5.05v
TBA_VDDP = 5.06v
R7020 = 5.27v

Diode mode to ground checks on USBC chips:

UB300
LDO_3V3 = 463
LDO_1V8A = 553
LDO_1V8D = 505
LDO_BMC = 548

UB400
LDO_3V3 = 463
LDO_1V8A = 558
LDO_1V8D = 505
LDO_BMC = 552

U3100
LDO_3V3 = 462
LDO_1V8A = 548
LDO_1V8D = 503
LDO_BMC = 542

U3200
LDO_3V3 = 462
LDO_1V8A = 552
LDO_1V8D = 504
LDO_BMC = 546

Voltage measurements on U7000
P_IN = 5.27v
AUX_DET = 5.27v
VDDA = 5.05v
VDDP = 5.05v
SMC_RST* = 0v
AUX_OK = 0.33v
AMON = 0v
BMON =0v

Any suggestions or advice greatly appreciated.
Thank you.

 

[2informaticos]

Be sure to use original 87/96W charger.
What is PPBUS_G3H voltage with battery connected?
Don't forget to connect the data cable.
Should be good to test with pre-charged battery.

Check SMC_USBC_INT_L level.

Any history available?

 

[joshAU]

Thanks 2infomaticos.

PPBUS_G3H = 11.04v with battery attached, with the data line connected as well.

SMC_USBC_INT_L = 0.24 with battery
SMC_USBC_INT_L = 0.04 without battery

No history available, other than the last time the customer used it, it worked.

 

[2informaticos]

There is a problem with (at least) one USB-C port.

Board turns on with battery connected?
Use R5226, or SW5200, for test.

 

[joshAU]

Thanks again for your help 2informaticos.

The board did not have R5226 or SW5200.
Both were not populated.

We found C3100 was shorted.
Removed and now get 20v and the board is working correctly.
Boots into OSX OK.

Thanks, once again for your help, I really appreciate it.

 

[2informaticos]

"The board did not have R5226 or SW5200.
Both were not populated."
Of course, these pads are just for test purpose.