I did the initial start up with the printhead unplugged and had nothing
Took the screen apart and put it back together got squares only unplugged the print head and got the splash and full screen setup
Now when I plug in the print head it’s all squares and the print head starts getting warm
Check the control board to see if the heater is on when you apply power.
Check the wiring on the print head Heater in the front positions thermistor in the middle fans at the back connectors.