A2485 820-02100 - Liquid damage over HDMI port. Turns on with no picture internal or external

[it-solve]

Turns on with a chime noise, capslock responds. No picture on internal, HDMI or USBc videos outputs.
Can see it appearing in apple configurator. Seems to be turning on.



Milk coffee liquid damage via the HDMI port. Mainly around UT520, HDMI port, QH501/2, UH502

PP5V0_HDMI_DDC_CONN - 5V
PP5V_S2_HDMI - 5V

 

[2informaticos]

Looks very uggly.
Possible CPU damaged on some data lines.

Check diode mode to ground at JP600 data lines; compare with good board.
LPDP_INT_HPD comes high?

 

[it-solve]

Tested with a spare board, which is not turning on, but I'm sure HDMI part is OK as no liquid there.


LPDP_INT_HPD Not sure how to test with screen connected?

With disconnected screen
LPDP_INT_HPD = 0.6V - when charger is 5V/0.5A, then 0V when chimes and switches to 20V

 

[2informaticos]

Puah, no test point available on the MLB; not sure if is accessible on the TCON.
I don't know if you can solder wire on the JP600 corresponding pin, to check.
This signal comes from LCD, so MUST be connected.

 

[it-solve]

Managed to measure with connected LCD. 1.12V when Macbook turns on. It goes 1.1V - 0V - 1.1V when chimed and capslock responds

 

[2informaticos]

At least LCD sends HPD signal and maintains it.
CPU should detect it.

 

[it-solve]

No HDMI or Internal even backlight though. What else I can try?

 

[2informaticos]

Extended corrosion, possibly affected internal copper layers.