after event power outage due to storm my xbox boots with extremely dim screen

Just a quick question. Did you recently have a thunderstorm in your area or have a power surge? I had a similar deal with my slim and it turned out it was due to a power outage during a storm. Thankfully I just bought and was able to take it back to
the store.

Have you tried booting into low resolution mode? Maybe something was changed and is ot compatible with the change setting. Low resolution mode basically reset your display settings to the lowest settings. To do this you press and hold the Xbox button and
the Eject button until you hear a beep to turn on the console. Note This will boot your console in a low resolution mode.

Have you gone through all the display settings and try adjusting them to see if can get any response. This might be a hardware issue if all devices work fine and multiple HDMI cables do not help. Is your console still under warranty?

I have seen this happen on My X Console when we have had a power outage or power fluctuation. Is it possible there has be a power outage or other power event since you last turned the console on?

Have you had any power outages and do you use a surge protector?.I have 2 consoles that do this same thing.We went through a month of storms and power outages and they were plugged in with no surge protectors.