Laptop black screen but external works

[kiwiturkey]

Hi, I have an Inspiron 15 7559 gaming laptop that has recently had LCD issues. The screen is black and doesn't POST unless I plug my laptop into an external monitor. Without the laptop plugged into the external monitor, the LED lights flash 7 white and 2 amber which means that there Is a LCD issue. I can only use my laptop with the external monitor plugged in prior to powering up the laptop since the laptop won't even show BIOS without an external monitor.

I've tried several solutions like unplugging the battery and resetting the laptop with just the AC adapter by drawing out residual power (30 sec, 1 min, 2 min). Also, I did the BIST test and all colors were shown correctly and there were no artifacts which makes me think that the problem isn't with the GPU itself. Could the problem lie with the LCD cable being damaged?

Also, the laptop screen has worked once a day for the past couple of days when this problem started coming up. I did other things such as uninstalling the Intel onboard as well as the dedicated GPU from the Device Manager and this actually worked when I rebooted the laptop with the HDMI cable in. The external screen allowed the laptop to boot and then when it went into Windows and reinstalled the drivers by itself my laptop screen worked again. As soon as I restarted my laptop without the external monitor though, the laptop went black again with the 7 white 2 amber flashing.

Any insight would be greatly appreciated. I also ordered a new LCD cable and will take apart my laptop to reinstall that today and will give the results.

 

[webworkings]

It could be the display itself or it could just be the cable that connects it.

I would start with opening it up and checking the cable. Disconnect it on both ends and then reconnect it. This may well solve the issue. Also, check if the cable is being pinched, caught on something, etc. You may even try replacing it. Should that not work, then I would look at the display.

Now if the laptop is under warranty, I would contact the manufacturer. However if it isn't, then you have to choice of doing the work yourself or talking it to a tech.