Model #DMT2420S, this counter top microwave (it can also be built in using a trim kit) stopped working for the customer the same time the LCD display began displaying strange patterns instead of the usual touch panel. The remaining buttons on the user interface operated properly, but because the 0-9 buttons are part of the display, the unit could not be used.
Many microwaves us a touch panel with raised buttons for user input and an LED display is used for information output. This microwave uses LCD technology to not only display output information to the user, but the display can also change dynamically depending on the operation selected and the mode the unit is operating in. The look of these displays are very nice and the ability to alter the interface is a unique feature of these higher end microwaves. The unfortunate side is when they stop operating, the units stop working as well.
With the control panel removed, the control board and LCD panel can be accessed and tested for operation. Because the LCD board is all self contained on it's own board, the trouble shooting process is quite simple. Replace the board. Which is what I did to get this unit back up and running. Once the LCD board was replaced, everything on the microwave started working again just as it should.
I know the price of this board makes the repair rather expensive, but when the unit matches everything else in the kitchen, sometimes its your best bet to ensure everything stays as a matched set.