Hi,

There is a hardware solution to the HDMI problem with Dell XPS 17 (L702x).

The problem: No output on HDMI.

Details: The laptop won't output to HDMI. The laptop's screen is connected to the CPU video module. The external monitor is connected to the NVIDIA GPU. The problem is that with a faulty I/O board, the monitor will use the Intel video module. Which is wrong.

The solution: call Dell are replace the I/O board. But first, eliminate other issues:

1. Re-install Windows to ensure it's not a OS problem.

2. Re-install original Dell drivers, even if they are old. (Install first the on-board Intel driver, than the NVIDIA driver). 

3. Test with new and Beta drivers.

4. Test the HDMI cable with another computer.

5. Test the monitor with other computer. (Try to reset the monitor to default settings).

6. Check HDMI connectors.

7. Call Dell support, ask for a new I/O board.

Important: After re-installing Windows and Intel drivers, disable from Intel Video menu > Power > On battery > Power Conservation Features and change to 60Hz.

Important: If NVIDIA GPU is not used during certain app (game, 3D) check NVIDIA panel > Manage 3D settings > Program settings > Select an app, than choose NVIDIA GPU. For extra features, search NVIDIA Inspector and apply custom settings.