The LCD on my Sharp microwave oven recently failed, beginning with a few segments but quickly getting worse. I’ve seen quite a few similar models with the same problem and a quick Google search proves this. Sharp even offered a recall at one stage.
If your microwave oven suffers a similar fate and you could give this a try. Note that it is not actually an LED display as some seem to think; Sharp have simply done a pretty convincing job of making the LCD look like one.
First up, only open your microwave if you have experience working with electrical devices. Microwaves operate using very high voltages that can remain stored in a capacitor even after switching the unit off.
Disconnect the microwave from the supply and remove the cover. Do not touch the magnetron, transformer or capacitor.
Take a note of all the connections to the power supply PCB on the rear side of the front panel. Disconnect all of the wires.
The front panel is held on by a single screw near the top. Once this is removed, open the oven door and slide the panel upwards to remove it.
The LCD is mounted on the back of the controller PCB and connected via a ribbon cable. This cable is attached using what appears to be conductive glue. I guess this glue breaks down over time causing dodgy connections to the LCD.
I was able to mostly fix the display in my microwave simply by running a hot soldering iron across the black glue. This may work for you. It will probably require some trial and error until the display works. Just don’t connect the microwave to the mains supply with the cover removed!
I decided to scrape all of the black glue off and repair each joint using a conductive pen. As the pen is quite clumsy (it’s basically correction fluid with silver instead of white pigment) I found it easier to draw a continuous line across the contacts, then carefully scrape away the excess between each pin. Afterwards I covered it with a strip of hot glue for protection.
While not particularly elegant this has fixed the display completely!