HP DV7-4065dx LED problem

[robotech]

Hello,Here's a good one for you guys.
I have a HP DV7-4065 laptop. It worked great for almost two years.
Suddenly, the screen stays black, the Caps Lock LED blinks four times (graphic card problem according to the code listing).
Here's the weird part.
Altho the code says graphic card, and the laptop screen stays black, I can connect to an external with either an hdmi or vga output. Works fine.
Yet, no integrated display.
Now, if the code says graphic card problem and no led display (led, not lcd, no back light or inverter), then why does an external monitor work?
I did several hard resets and removed all but one stick of memory, still the same.
So, I have orred a new led cable, and if that doesn't fix it, I will go with a new led screen. less than 90.00 total.
IF that doesn't fix it, then I would have to suspect the vid chip on the motherboard. Even at another 100-120, it's still cheaper than a new laptop and the DV7-4065 is still a fast machine.
Am I on the wrong track?

 

[jarotech]

Now, if the code says graphic card problem and no led display (led, not lcd, no back light or inverter), then why does an external monitor work?

Because you have different outputs on the gpu, the screen, the hdmi and the vga are not connected on the same pins. The problem you probably have, is some part of the gpu is defective but not all of it. Or it could be a trace between the gpu and the screen, who knows.

 

[robotech]

things just kept getting weirder, so replacing motherboard.
Seems like there was a different vid problem every time I turned it on.Will post back after I get it and install it.
So definitely suspect the gpu.