820-01598 Won't work with LCD connected

[bjf]

This board had very minimal signs of liquid-damage near the USB-C ports. I attached a picture. It's not the best but you can see where the spill hit. This will turn on and work fine with an external monitor but if I attach the LCD it won't display anything on either screen. Any ideas or hope to fix this? Or is this just another Touch Bar that will only work on an external monitor?

 

[2informaticos]

Liquid near backlight coil?
That is very bad.
Clean the area and check for any short, w/ and w/o internal LCD connected.

The backlight area is not enabled if LCD is disconnected.
So a short there is not detected with only external monitor.

Do you have USB activity, or board doesn't turn on at all?
When connect internal LCD...

 

[bjf]

The board definitely turns on. Caps Lock lights up. Fan is spinning up after a minute. But with the internal LCD connected, the external monitor does not come up.

 

[bjf]

Being that I don't have a board view, I did a common sense search for shorts and couldn't find anything that seemed wrong. Not sure what more I can do.

 

[2informaticos]

Did you check for any short on backlight output side?
With LCD connected, of course.

 

[bjf]

No shorts, but pin 6 is reading 1.6 in diode mode and pins 10 and 14 are reading open. They're all supposed to be in the .700 range so I'm thinking this might be a lost cause.

 

[2informaticos]

OL readings could mean broken traces.
But there could be some series capacitors; that will explain OL readings.

Did you try known good compatible LCD assembly?

 

[bjf]

I did additional testing with the LCD disconnected and those lines were open and it looks like they all just lead to the CPU so that's why I was thinking I was out of luck. And yes, tried my known-good test screen. Also, without a schematic/boardview, I'm not going to be able to run these down properly.