Alan H Fayetteville , NC February 02, 2017 Appliance: Samsung Dishwasher DMT400RHS/XAA Samsung Dishwasher Dmt400rhs/Xaa / : My dishwasher would not power on. How to replace Assy Display;Dmt400,Ct50. To fix my dishwasher I installed a new display circuit board (DMT 400). First step was to disconnect the power at the circuit breaker. Next unscrew the 12 screws holding the inner door shell from the outer door. Locate the circuit board near the top of the door, remove the two wiring harness connectors from the circuit board, remove 2 screws holding the board to the door.Pull the old board out,slide the new board in place and reverse the other removal steps. Very easy fix.Working perfect again!! 1 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 15-30 minutes