Nobody likes a microwave keypad that stops working – it can ruin your meal reheating plans. There are many possible causes of keypad failure, from dirt and grime built-up to electrical issues. This guide will help you diagnose common problems like faulty membrane switches or control board defects. Armed with some troubleshooting tips, you can try fixing your keypad yourself and avoid an unnecessary service call. Let’s explore the most prevalent causes of microwave keypad failures.
Membrane Switch Failure
Membrane switches are a very common reason why microwave keypads stop working properly. Let’s learn more about what membrane switches are, why they fail, and how to troubleshoot them.
What is a Membrane Switch?
A membrane switch is a thin layer inside your microwave keypad buttons. When you press a button, it connects two conductive traces on the membrane to send a signal. Membrane switches are made of flexible plastic or polymer material.
What Causes Membrane Switches to Fail?
There are a few reasons membrane switches can fail over time:
- Damage from wear and tear – Constant pressing of the buttons can cause the thin membrane to crack or deform. This damages the conductive traces.
- Liquid spills and cleaning chemicals – Spilling liquids or using harsh cleaners on the membrane can corrode the conductive traces.
- Improper cleaning – Scrubbing too hard on the membrane can damage it.
Signs Your Membrane Switch is Failing
How do you know if your membrane switch is causing issues? Here are some common signs:
- Unresponsive keys – Pressing a key does nothing. The membrane switch is likely broken.
- Sticky keys – A key works sometimes but not always. This indicates the membrane is starting to fail.
- Inconsistent responses – The same key gives different results each time. The membrane switch is likely corroded or damaged.
Troubleshooting Steps
If you suspect a faulty membrane switch, follow these troubleshooting steps:
- Inspect the membrane – Open up the keypad and visually inspect the membrane for any cracks, tears, or corrosion.
- Clean with mild detergent – Use a soft cloth with mild soap and water to gently clean the membrane. Harsh cleaners can damage it more.
- Check for blockages – Look for any debris, grease, or foreign material that could be blocking the membrane from making proper contact.
- Test button responses – Check if all keys are responsive after cleaning and clearing any blockages.
- Replace membrane – If keys still don’t work, the membrane likely needs full replacement. Purchase a new membrane switch specifically for your microwave model.
Control Board Issues
The control board is the brain that controls all of the microwave’s functions. Let’s go over what the control board does, how it can fail, and troubleshooting tips.
What Does the Control Board Do?
The control board is like the computer inside your microwave. It:
- Processes button presses on the keypad
- Controls the microwave power levels
- Runs the display panel
- Monitors sensors like the door switch
Without a working control board, your microwave can’t function properly.
What Causes Control Board Failure?
There are a few common reasons the control board can malfunction:
- Physical damage – Dropping or impacting the microwave can damage the sensitive components on the board.
- Power surges – Electrical spikes can fry the circuits on the board.
- Component failure – Parts on the board, like capacitors or transistors, can fail over time.
- Corrosion – Moisture seeping into the unit can corrode the board.
Signs of Control Board Failure
How do you know your microwave’s control board is acting up? Here are some key signs:
- Unresponsive buttons – The keypad doesn’t respond, but the membrane switch is fine.
- Erratic behavior – Microwave starts randomly or displays odd errors.
- Microwave won’t start – No power at all. The control board is likely dead.
Troubleshooting the Control Board
To troubleshoot a faulty control board, follow these steps:
- Inspect for physical damage like burns or cracked components.
- Check all wire connections to make sure they are secure.
- Look for corrosion and moisture damage.
- Test with a multimeter for shorts or bad components.
- Replace the control board if damaged. Make sure to get the correct part number.
Electrical Connections
The wires and connections that transmit power and signals in a microwave are important to check when troubleshooting. Let’s discuss how electrical connections can cause problems, symptoms to look for, and troubleshooting steps.
How Do Electrical Connections Fail?
There are a couple of ways the electrical connections in a microwave can fail:
- Loose wires – Vibration and normal use can cause wires to become loose from their terminals. This interrupts power flow.
- Corrosion – Moisture can corrode or oxidize connections, increasing resistance. This prevents signals and power from transmitting properly.
Signs of Bad Electrical Connections
Watch for these symptoms that point to faulty electrical connections:
- Dead buttons – If the keypad or certain buttons stop working, a loose wire is likely.
- Intermittent issues – The microwave fails randomly and unpredictably. Corroded wires that make poor contact can cause this.
- Won’t start – No signs of life at all indicate an open connection in the power wires.
Troubleshooting Electrical Connections
Follow these steps to troubleshoot electrical connections:
- Remove the outer case to access the wires.
- Inspect connections for corrosion, damaged terminals, and loose plugs.
- Check wires for cracks, burns, or exposed copper.
- Clean contacts gently with an electrical contact cleaner.
- Reseat all connections and replace damaged wires.
Power Issues
Problems with the power supply can definitely cause a microwave keypad to stop working properly. Let’s go over potential power problems, symptoms, and troubleshooting steps.
What Power Issues Cause Problems?
Here are some common power-related failures that can lead to keypad problems:
- Power surges – Spikes in voltage from the outlet can damage delicate electronics.
- Electrical storms – Nearby lightning strikes can create power surges that fry components.
- Faulty wiring – Old wiring with deteriorated insulation or loose connections can interrupt power.
- Blown fuse – The microwave’s internal fuse may blow and need replacement.
Signs of Power Problems
Watch for these keypad failure symptoms related to power issues:
- Total failure – Microwave is completely dead. Check the outlet and cords first.
- Intermittent operation – Microwave works sometimes but not others. It could be a wiring issue.
- Burning smell – An electrical short may cause overheating and a burning odor.
Troubleshooting Power Problems
Follow these tips to troubleshoot power-related keypad failures:
- Inspect the power cord for damage. Make sure it’s plugged in firmly.
- Test the outlet with a lamp to verify power is flowing.
- Check for tripped breakers or blown fuses in the electrical panel.
- Look for signs of electrical short like burn marks.
- Replace the microwave’s internal fuse if needed.
Software Issues
Problems with the software or firmware can also lead to microwave keypad troubles. Let’s learn about software failures, symptoms, and troubleshooting.
How Does Software Cause Issues?
Microwave software failures typically stem from:
- Bugs – Faulty coding can make the keyboard unresponsive or act erratically.
- Outdated firmware – Old firmware may have compatibility issues with the keypad.
- Corrupted memory – Errors clearing memory can disable the keyboard.
- Incorrect settings – Wrong mode or function settings can make the keypad unresponsive.
Signs of Software Failure
Here are some keypad problems indicating a software/firmware issue:
- Keys work, but the microwave doesn’t – The keyboard works, but the microwave won’t start. Likely a firmware bug.
- Error code on display – An error code points to corrupted firmware.
- Some keys work – Partial keyboard responsiveness indicates a settings issue.
Troubleshooting Software Issues
Try these steps to troubleshoot software-related keypad failures:
- Check for available firmware updates from the manufacturer.
- Reset the microwave to factory default settings.
- Try operating the unit in different modes to isolate settings issues.
- If all else fails, work with an authorized service center to reprogram/update the firmware.
Conclusion
In this article, we covered the most common causes of microwave keypad failure and tips for troubleshooting them. Let’s do a quick recap:
- Membrane switches – These thin internal layers are easily damaged by wear and tear. Inspect and clean gently.
- Control boards – The “brains” of the microwave can malfunction from damage or component failure. Check connections and test with a multimeter.
- Electrical connections – Loose wires and corroded terminals interrupt power and signals. Inspect and clean all connections.
- Power issues – Surges, bad wiring, and blown fuses can cause keypad failure. Check cords, outlets, and internal fuse.
- Software bugs – Faulty firmware, corrupted memory, and bad settings can cause keypad problems. Try resetting and updating the unit.
We hope you found this DIY troubleshooting guide helpful. Being able to diagnose and fix your own microwave keypad can save time and money.
Here are some final tips:
- Carefully inspect each component and connection.
- Try the simplest fixes first before replacing complex parts.
- Always unplug the microwave and discharge capacitors before disassembling.
- Research your specific model’s common issues online.
- Consult a service manual for detailed diagnostics and repair procedures.
With some basic tools and troubleshooting know-how, you can often bring your microwave keypad back to life.