820-3476 - USB port not working.

Alan.L

Member
usb2.0 and usb3.0 not working.
tried flash drives mouse.

5v present on L4605.
5v present on usb port's power pin.

U4650
pin 10 - 3.4v


Diode mode on pin 5,6 of J4600
0.641
0.641

Diode mode on USB_EXTA_P and USB_EXTA_N
0.404
0.404


i've replaced U4650, its still the same.

USB port looks clean under microscope.
I/O board's usb port is working fine.
 
Last edited:

2informaticos

Administrator
Staff member
U4650 can be removed, bypassing D-Y data lines.

Check L4600 and C4620/21 integrity.
Compare diode mode readings on USB 3 data lines.
 

Alan.L

Member
USB3_extra_r2d_p has contunity to c4621
USB3_extra_r2d_n has contunity to c4620

USB3_extra_r2d_c_p has 0.341 on diode reading (same on a known working good board)
USB3_extra_r2d_c_n has 0.341 on diode reading. (same on a known working good board)

USB3_exrta_d2r_p has 0.352 on diode reading (0.379 on a known working good board)
USB3_exrta_d2r_n has 0.349 on diode reading (0.378 on a known working good board)


L4600 and C4620/21 integrity look ok. i've even replaced them, just in case.


i've compared every lines with a known working good board. all measurements matched.


fuked pch?




solder joints look ok under the shield




 
Last edited:

Alan.L

Member
no change, USB thumb drive doesn't light up. same as before.

5.1v is still present on pp5v_s3_ltusb_a_F after inserting a USB drive.
my usb desk lamp will power up ok.


 
Top