SOLVED 820-00840 5V looping on one port

[it-solve]

Hi Folks,

Have this A1708 820-00840 which is looping on one port 0 - 5V closest to the screen, while the other one is stable 5V closest to the trackpad.

Would you say this is a faulty USB-c controller? The one looping is the closest one to the screen which I believe is controlled by U3200.

All other voltages are looping including PP3V3_G3H when connected on that port.

When power supplied to the closest to the trackpad port, some of the measurements are:

PP3V3_G3H - 3.3V
TBA_HPWR_EN_L - 3.3V
PM_EN_P3V3_G3H - 5V
SMC_RESET_R_L - 3.3V
PPDCIN_G3H - 5V

Thanks

 

[2informaticos]

Compare diode mode readings on all LDO outputs of both chips.
The other chip should be the culprit...

 

[it-solve]

PP3V3_UPC_XA_LDO is shorting to the ground.
Does it worth checking possible shorting caps or shall I hit the U3100?

 

[2informaticos]

You can remove C3108 first, but very likely bad U3100.

 

[it-solve]

Thanks @2informaticos, the cap was okay. As suggested U3100 was the culprit.