Hi meich,
Thank you for using the Support Forum. Please take a look at the solutions for blank screen and see if any of these will help. If not please consider contacting your support centre for further assistance.
I have a Phaser 7400 that was given to me because it is not working corectly. the unit powers on and the status led is green and shortly turns red, there are a few moters running and seems like they would run forever if I didnt turn the printer off. the screen never has any thing on it except the back light. The control panel doesn't work either because I know the button pattern and can't get any test pages to print either. Thanks for the advice!