HP laptop with a dead screen.

[horseatingweeds]

I've got a question about a < 2-year-old laptop I'm working to fix. It's screen seems dead. I've checked the obvious things, like operating system screen settings and brightness. And the user says the screen just went blank one day. So I'm guessing the display was either defective or was damaged by someone.

Here's my question though. I can't get any video signal from the HDMI port, but I can run a monitor fine from the laptop's VGA port. Could this have any diagnostic implications. The more I think about it the more it seems like the HDMI port must be bad. Because doesn't the graphics card simply convert the digital signal into analogue for the VGA port? So in other words, no, the fact that I can not run a monitor off the HDMI port probably has nothing to do with the laptop's display not working?

Any advice on this would be appreciated. I plan to order a new display and install it myself. I've studied the manual for this laptop and watched a Youtube video of someone installing this display. I think I can handle it. I've already taken it apart half way just to check connections and for any other obvious problems.

HP Pavilion dv4
Windows 7

 

[Dngrsone]

Have you tried to verify this is not a bad backlight inverter?

Keep in mind, also, that some of the DV4 series with Nvidia GPUs are covered under a class-action settlement-- you might be able to get a discounted or free replacement if the GPU itself is bad.

 

[horseatingweeds]

Thanks Dngrsone. How might I verify the backlight inverter? The screen is totally dead. I don't see even a hint of anything.

I checked the NVIDIA suit info, and this laptop model is not included.

 

[Dngrsone]

If it's just the backlight, then you might be able to see some hint of video by shining a light obliquely through the panel. If it is just plain black, then it is more likely a bad screen or cable.

 

[Indigo]

but I can run a monitor fine from the laptop's VGA port. Could this have any diagnostic implications. The more I think about it the more it seems like the HDMI port must be bad. Because doesn't the graphics card simply convert the digital signal into analogue for the VGA port? So in other words, no, the fact that I can not run a monitor off the HDMI port probably has nothing to do with the laptop's display not working?

To answer this question, the HDMI is likely not bad, just not enabled, or needs to be set up (HP's are odd like that sometimes I've noticed), but the fact that the other port works fine, means that it's likely not a problem with the GPU, just the screen. Having dealt with the class action stuff in question myself, you would not be able to use the system much, if at all, if it were affected by the class action.

 

[horseatingweeds]

Thanks og, I think it must be the display. I can buy a new display for $100. I'm hesitant though. I'm fairly confident I could replace it myself, but not confident that there will still be hidden problems demanding more money to remedy.

Also, I cleaned the keyboard with some alcohol, and now it's behaving erratically. (Isn't alcohol safe to use?) The disk drive is working, but also damaged. So I'm thinking the best thing to do with this poor thing is to run it as a desktop - plug in monitor, mouse, and keyboard. That way, no one is putting money into a messed up laptop.

What do you think?

 

[Dngrsone]

Alcohol is safe as long as it has thoroughly evaporated before you apply power.

 

[horseatingweeds]

Hmmm... I let it dry for about 8 hours, then reinstalled it and it didn't work at all. Then I let it dry for 24 hours, and for the 24 hours following, it was crazy, typing on its own, some letters printed two, the space bar added a new line. But now, I just tried it, and the keyboard seems fine. Strange... I guess moisture got in somewhere and needed a few days to get out. I figured it would dry in no time since I was using 70% isopropyl.

 

[Dngrsone]

70% iso is 30% water... and water is insidious--- it takes a while to dry out of nooks and crannies.