The Diagnostic Screen can be initiated by either of the following 4 ways:
Ensure your device is powered on.
Initiate the Diagnostic Screen:
Using Remote Control
If your device has a remote, point the remote towards the device and press the numbers 1 3 9 7, in that order.
Using External Keyboard
If you're using a USB keyboard, you can enter 1 3 9 7, in that order and hit enter.
Using External Mouse/Touch-Screen
If your device is a touch-screen, tap the Top Left - Top Right - Bottom Right - Bottom Left corners of the screen.
Unplugging and Plugging in Device
Physically unplug and plug your device back in twice within a two minute period.
The Diagnostic Screen should look like this:
Need to dismiss the diagnostic screen?
The diagnostic screen will dismiss on its own after two minutes, but if you would like to it to dismiss sooner, simply repeat the method you used to initiate the screen to dismiss it.