Hi @Dazechan

After the LCD and LCD cable replacement, is the external monitor/TV still working fine?

@Alienware-Eimy Hey!

Yes it is still working fine , everything but the laptop screen itself.

If you already ruled out any software issues, by updating drivers and even re-installation of Windows, then this could be related to the motherboard slot (the one that connects the LCD cable).

@Alienware-Eimy 

I've already done a format and nothing has changed so far. I have yet to try an older bios version and re-installation of GPU drivers even though I believe it's pointless as there are no flickering pixels on the external monitor.

If the problem is the motherboard slot like you said , is it repairable or I have to replace the entire motherboard? 

Plus , is there any way to verify if that is really the problem by myself?

Also I've tried to run the LCD test by SupportAssist and there is no flickering on single color pictures. Red/White/Black/Blue/Green are all fine. Only Gray is flickering in the test. The mass pixel flickering occurs when there is more than 1 color displaying on the screen. 

Thanks for your time. 

I will advised you to rule out any software issues first, but if the issue continues yes, looks like it will be related to the motherboard. In this case you'll need to replace the entire motherboard. But we can't guarantee resolution since we are not the ones troubleshooting the system.

Just make sure that this third-party store did a proper repair when replacing the LCD and the LCD cable.

@Alienware-Eimy 

Is it possible to have Dell check out for my laptop? It is out of warranty and that's the only reason I brought it to a third-party store.

Can I PM you the service tag ?

For out of warranty systems you need to call the out of warranty department at 866 287 6727 opt#4.