Diagnosis
The machine works, so power is getting to the pump. The blank screen means the low-voltage control circuit or the display itself isn't getting power. The most likely point of failure is the connection from the main unit to the handle/display assembly.
How to Fix It
Check the control cable that runs from the back of the main unit up to the handle. Make sure both ends are plugged in securely. The connector at the base of the unit can get jostled loose during movement or storage. Unplug it, check for bent pins or debris, and plug it back in firmly.
If That Didn't Work
If the connections are good, the issue could be internal. There's an internal fuse on the control board for the display circuit. You'd need to open the casing to check it, which is a more involved repair.
Heads Up
You can operate the washer with a blank screen—the pump runs based on the trigger. You just lose the ability to see error codes, pressure settings, and the timer.