No video or backlight on screen. Motherboard or screen problem?

[computer_newbie_30]

Laptop: HP dv6-6117dx

I spilled coffee on my laptop.

Laptop screen is completely black with no backlight.
There is no video feedback, not even if I shine a flashlight on the screen.
However, if I connect the laptop to an external monitor, it works fine.
I replaced the video cable, screen still shows no video or backlight.

I'm boiling down this issue to 2 problems:
- Screen needs replacement
- Motherboard needs replacement

It just doesn't seem likely that it's the motherboard because it still boots up and works with an external monitor. Someone please help. Also, if I open "Screen Resolution" in Windows 7, only the external monitor is shown to be display. The mobile display that usually shows up for laptop screens isn't there. Could this indicate motherboard or screen failure? Remember... I already replaced the video cable.

When I open up the laptop, there is some brown (maybe rust or coffee residue?) stuff that can be scraped off near the video input port on the motherboard.

 

[inzone]

Well it seems obvious to me that the screen is the problem here because if you connect an external monitor to the laptop and the motherboard was no good then you would get no display on it. I know you said you replaced the video cable but when you spilled the coffee was the laptop closed or open and where did the coffee go , did it reach up to the screen at all. If you unplug the video cable from the screen can you notice any liquid or wet look in the connector? Can you blow it out with can air o airr comressor , vaccum or some dry cloth , then leave the connection open to see if it will dry out. Sometimes if you get all the liquid out and let it dry real good it will end up working.
I have water cooling and I accidently spilled some water on the psu and it started smoking, I of course shut it off and unplugged right away. I dried it up and blew it out with an air hose but it wouldn't start so I thought it was dead, so I took it out and set it aside for a few days and used my bqackup psu. After a few days of drying it turnedback on and I've been using it ever sense.
So if you have the time just unconnect the video cable and see if you can dry it out the best you can and let it sit for a few days and dry out. Then try it.

 

[computer_newbie_30]

It seems rare for a screen to stop working after coffee is spilled on the keyboard. Is it possible for part of the motherboard, like say, the LCD cable input port to be damage from the coffee?

 

[computer_newbie_30]

So should I purchase a new motherboard or screen?