Zbook turns off before POST due to display problem
I am currently trying to repair a ZBook 17. After plugging in the power adapter the leds blink for 3 seconds and it turns off again, the screen remains black.
After a while of troubleshooting i found that when I unplug the display cable from the motherboard OR from the display unit (and connecting an external VGA screen) it gets to POST.
Can this be caused by a bad display cable although it is causing no error when it reamins plugged in the motherboard and is disconnected only at the LCD? How can I determine what exactly is causing the issue? For all I know it could also be a bad LCD or even a problem with the graphics card or motherboard.
I don’t want to buy replacement parts before I know for sure what is causing the problem. Can I narrow it down further without buying any parts?