820-00840 / No boot / PP3V3_G3H Short to ground

Papaille

Member
Ok thanks for all this explanations.

all i know it's it is an oem charger an cable, but cable was partially ruined (needed to flex it in many ways to have signal on the board, that was done by previous owner. Can Suppose a voltage dropped to data line inside the cable) Since the beginning of my revival experience, i use brand new cable and oem charger.

U2800 seems to output correctly on second port, but nothing on first.
Is there an way or an order to test U2800 and PCH properly?

thanks again
 

Papaille

Member
So I have unsoldered redriver chip from the board.
Symptoms are still the sames (working outpout monitor on u3100 linked usb-c port, nothing on u3200 linked, fully working usb détection, management and charging on u3200 linked port, only charging and Sometimes détection on u3100 linked port)

a way to investigate more?
 

Papaille

Member
Suppose that i have already done that (tell me if it’s incorrect) when I found that d+ pin on bottom side of the u3100 linked usb-C port was at 0.042 in diode mode instead of O.L. on other ports.

anything else I can check? Maybe U2800 involved in my issues?
 

2informaticos

Administrator
Staff member
HDMI output is done through U2800.
But normal USB activity should be same on both ports.
You may have damaged traces, possibly into internal copper layers.
Some protection diodes may have leakage.
 

Papaille

Member
Ok. So I suppose next thing to do is remove massive shield upper u2800 area and see if something is bad along j3300, like a protection diode or burn resistor right ?
 
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