Dell U4320Q display Flicker and goes black (blanking)

I have a Dell U4320q that randomly flickers, then flickers in only the top few lines of the monitor, then goes black.

This happens both with a computer connected and I've also noticed it/recreated it running just the Dell LCD conditioning loop - so I know it's not a cable/connection.

On occasion a simple power down/power up will reset the issue and things will work fine but on occasion the power down doesn't work and I'm stuck with a big black screen.

Any thoughts on which module is bad? Power? Interface? Any help would be appreciated.