820-00928 turn on, but doesnt detect usb

[Yoel Ren]

It have 20v on all usb port, can charge and turn on fine, but doesnt detect external usb
no 5v on L3500..u3500 area looks fine

 

[2informaticos]

What about UPC_X_5V_EN?

 

[Yoel Ren]

UPC_X_5V_EN measured at u3500 is 0.4v
R3032 is 100k good

 

[Yoel Ren]

from what i dechiper, upc_x_5v_en is either comes from u3100 or u3200, so how do I determine which one is the culprit?

 

[2informaticos]

The other two USB-C ports are powered from LB700.
And UPC_T_5V_EN comes from UB300/400.
Same behaviour on them?

 

[Yoel Ren]

upc_t_5v_en is same at 0.5v

 

[2informaticos]

Check diode mode to ground at 5V_S4_X/T_USBC.

 

[Yoel Ren]

5v_s4_T_USBC diode mode is 0.161
5v_s4_X_USBC diode mode is0.174

 

[2informaticos]

The webcam works?
If not, can be PCH issue.

However, try another USB-C hub...

 

[Yoel Ren]

i notice that some port detected external usb..
but one particular port kill my external flashdrive ( it smoke when I plugged it ), its the left second port which is closest to the trackpad ( the sidethat doesnt have headphone jack ).
customer actually have told me this particular port killed his soundcard too..
maybe thats the one causing some problem.. how can I detect the fault ? if i charge there, its fine..

 

[Yoel Ren]

i think it correspond to u3100, should i change it ? or is something shorting ?

 

[2informaticos]

Q3100 is shorted then; change it...

 

[Yoel Ren]

do you mean q3100 / u3100 ?
i changed q3100 but still the same, now all port doesnt detect..

 

[2informaticos]

The board has 4 input MOSFETs, one for each channel.
You must check them, or change directly.

 

[Yoel Ren]

there's one damaged crystal near u2800, changed it and all good now, its not in a schematic but. its. beside .... ( i will insert the componen name after i get. back. to shop)