I have dell vostro 14 3000 series, Recently laptop screen is gone black. I can see the external display working fine. I did run BIST, It completed successfully and able to see the colors on the builtin display during the test.
I also ran pre-boot diagnostics(Fn+power) without any issue. Please help me to diagnose the issue.
Check the cable that runs between the mainboard and back of the display panel. If it's damaged, replace it. That doesn't solve the problem, the next suspect is the mainboard.
Thank you for the quick reply.
cable looks fine, and today I closed the lid and opened it back, it started blinking. Right now, I can see the display on the screen, but continuously blinks. black screen issue started after keeping the laptop idle for a week, and it started blinking after using it for a day.
Replace the video cable with a new one.
Since the display works in BIST (and assuming it doesn't flicker there), if the video cable fails to solve the issue, replace the mainboard.