Microwave Display Not Working? Here’s How to Repair It

It can be incredibly frustrating when your microwave display suddenly stops working properly. A blank or glitchy display prevents you from easily using all the microwave’s functions and cooking food. Before you resort to buying a whole new over-the-range or countertop microwave oven, it’s worth troubleshooting the issue to determine if a DIY repair is possible.

The information in this article may not apply to your specific appliance model. We recommend consulting your manufacturer’s documentation or contact us with any questions.

The most common causes of microwave display issues

There are two main components that when faulty can cause the display on your microwave to stop working properly. By determining which part is causing the issue, you can ensure you obtain the correct replacement part to get your appliance fully operational again.

Faulty display board

The most likely culprit of a display malfunction is a damaged display board inside the microwave. This board powers and controls the functionality of the entire display. When it’s defective, you may see only partial display output, scrambled numbers and text, or in severe cases, no visual output at all.

Some signs that point to a faulty display board include:

• Display only lights up partially
• Segments of numbers/text missing
• Display flickers or blinks on and off
• The display lights up but is scrambled or frozen

If you see any of these issues, it’s best to test or replace the display board first before investigating other microwave parts.

Defective main control board

While less common than a display board defect, a damaged main control board can also lead to a non-working display. This main board controls all of the microwave’s functions.

You may be dealing with a faulty main control board if:

• The display is completely dark/blank
• The microwave is completely dead and unresponsive

In some cases, both the display and main boards could be malfunctioning. It’s a good idea to inspect the display board first for any burnt components before purchasing a main control board replacement.

Safety first – electrical hazards inside a microwave

Before attempting to remove or replace any internal microwave parts, you need to be aware of the major electrical hazards inside these high-powered appliances.

High voltage and current

Microwave ovens produce very high voltage and current to generate the microwave energy that cooks food. This electricity runs through multiple components including the display board, transformers, control board, magnetron, and high-voltage diode.

Accidental contact with these parts while powered on could result in severe electric shock, burns, or death.

A capacitor holds residual charge

Even after unplugging your microwave, there is still a danger of electrocution. The high-voltage capacitor can hold a lethal electrical charge long after being disconnected from power.

To avoid being shocked, you should allow time for the capacitor to fully discharge after unplugging the microwave. Never touch internal components unless you’ve confirmed the capacitor has been discharged.

Inspecting a faulty display board

If you do wish to troubleshoot and replace the display board yourself, proceed with extreme caution. Here are some steps for safely inspecting a potentially faulty microwave display board:

Unplug and allow discharge time

Do not attempt this if you are uncomfortable or uncertain about the process. 

Before doing anything else, unplug your microwave from the power source and discharge the capacitor.

With your microwave unit unplugged, touch the blade of a well-insulated screwdriver to one terminal. Gently slide the screwdriver forward until it reaches the other terminal, holding it there for a few seconds. Be aware that this often results in a loud and startling ‘POP’.

Repeat this procedure in order to create a short circuit between each capacitor terminal and the chassis (bare metal mounting plate surface). This same method can be applied to a capacitor having three, and not two, terminals.

Locate display board

Inside you will see a circuit board with an LED display connected by wires running to the main control board. This is the display board you need to test.

Check for damaged components

Closely examine the display board for any damaged parts like burnt marks or discoloration. Look for popped capacitors or loose solder connections. Any visible damage likely means the board needs replacing.

Check wiring and connections

Also, inspect where the display board wires connect to the main board. Check for corroded or loose connectors that could cause display issues.

If you find any damage on the display board itself or at its wiring connections, a replacement board should resolve the display problem.

Display still not working? Main control board issues

If you install a new display board but the microwave display still doesn’t turn on, the issue may lie with the main control board instead. Here are some tips on determining if the main board is malfunctioning:

Inspect the main board and wiring

With the microwave casing off, examine the main board for any burnt spots or damaged capacitors. Also, check that the display board wiring is securely connected to the main board interface.

Test touchpad buttons

See if pressing the touchpad buttons elicits any response. The main board receives input from the keypad. If the buttons are completely unresponsive, that can indicate a main control board is needed.

Verify magnetron function

Test to see if the microwave energy is still working. Place a cup of water inside and activate the “Add 30 Seconds” button. If the water doesn’t heat up at all, the magnetron is likely not receiving power from the main board.

If you suspect the main board is faulty after testing, replacing it may be necessary to get the microwave fully operational again. Handle this repair carefully given the risks of high voltage.

Once you’ve determined that the display board or the main board is the root cause of the microwave display issue, you’ll need to find a suitable replacement part. You will need to locate your model number to get the correct part.

More Information

Thanks for reading! If you have any other appliance repair needs or projects, you can find other resources and our DIY blog at AppliancePartsPros.com. There, you can enter your model number and use our compatibility tool to order the exact parts you need. Most orders arrive in 2-3 business days.

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