SOLVED: A1706 820-00239 - USBC's not detecting USB nor providing Video Output, but charging - Liquid Damaged

it-solve

Member
A1706 820-00239 which had extensive liquid damage.
Located and removed the short on PPBUS_G3H. Now turns on, charging and works fine. Passes Apple Diagnostic. The only issue seems to be not USB and HDMI output via either of USBCs. No light on a USB drive.

Tried SMC reset. Another strange thing is when I do a PRAM reset, I can see the screen flashing for it, but no chime sound. Can't remember if this one had a chime sound or not.

Haven't worked on USB/Video via USBC's before. Where do I look first?
 

2informaticos

Administrator
Staff member
Check for voltage at L3500 and LB700, when connect USB device to corresponding port.
Compare diode mode reading with known good similar board.
Also check R3501/06 and RB701/06.
 

it-solve

Member
End up being shorted PP5V_S4. Shocking how it was turning on and functioning with shorted S4 rail.

Replaced UB700 as it had short on PVCC line. R3501/6 measured fine but had little dots on top. Replaced in case.

Thanks again
 
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