LG Microwaves have been my favorite since I started using them. Just as it is enjoyable, sometimes we may face some challenges that will make the use difficult, like having a faulty touchpad.

You may have encountered a problem with the touchpad not responding or working correctly. This can be very frustrating, especially when using your microwave to cook or heat food. Fortunately, I have been there, so I decided to help you with some simple ways to diagnose and fix this issue without calling a professional or buying a new microwave.

I will show you how to repair the L.G. microwave oven touchpad in easy steps. There are a couple of things we will learn today, which I have listed below.

Identify the possible causes of the touchpad malfunction
Test the touchpad and the control board with a multimeter
Replace the faulty touchpad or the control board if needed

Reassemble the microwave oven and test it for functionality

This guide can help you repair your L.G. microwave oven touchpad and save money and time. You will also learn how microwave ovens work and how to troubleshoot them.

This guide suits beginners with experience using tools and handling electrical appliances. Before we start, let me give you a brief overview of how a microwave oven touchpad works and why it may fail.

How a Microwave Oven Touchpad Works and Why It May Fail

A microwave oven touchpad is a membrane switch comprising two layers of flexible plastic with conductive traces printed on it. The atoms form a matrix of rows and columns corresponding to different touchpad buttons or functions.

When you press a button on the touchpad, you create a contact between the two layers. Upon pressing the clock button for a second time, the circuit is activated, prompting the transmission of a signal to the control board. The control board then interprets the signal and executes the corresponding command, such as setting the time, power level, or cooking mode.

The touchpad is connected to the control board by a flat ribbon connector, usually attached to the front panel of the microwave oven.

The control board is the brain of the microwave oven, which controls all the functions and components, such as the magnetron, the fan, the turntable, the display, and the touchpad. Below are various reasons the touchpad may fail .

Wear and tear: Over time, the plastic layers of the touchpad may wear out or crack, causing the traces to break or lose contact. This may result in some buttons not working intermittently or working incorrectly.
Moisture or dirt: If the touchpad is exposed to water or soil, it may cause a short circuit or corrosion of the traces. This may result in the touchpad not working at all or erratically.
Damage or loose connection: If the touchpad or the ribbon connector is damaged or loose, it may cause a disruption or a loss of signal between the touchpad and the control board. This may result in the touchpad not responding or responding slowly or inconsistently.

How to Test the Touchpad and the Control Board with a Multimeter

To test the touchpad and the control board, you aim to get it right and avoid any mistake you may make that may cause more problems to you. To maintain the accuracy, you need to follow this steps below.

Remove the cabinet of the microwave oven

The cabinet is the metal cover that encloses the microwave oven. To remove it, you need to unscrew the screws that hold it in place and slide it off. You may need to use a pair of pliers to remove some of the screws, as they may be tight or rusty. In addition, it will be necessary to have a screwdriver on hand.

Locate the touchpad and the control board

The touchpad is usually attached to the front panel of the microwave oven, and the control board is generally mounted behind it.

You may need to remove the front panel to access the control board. To do this, you need to unscrew the screws that hold the front panel in place and disconnect the wires that connect it to the microwave oven. Be careful not to pull or cut wires; label them if necessary to reconnect them later.

Disconnect the ribbon connector from the control board

The ribbon connector is the flat cable that connects the touchpad to the control board. To disconnect it, gently pull it out from the socket on the control board. Exercise caution to prevent harm to the connector and socket, as they are fragile and may break easily.

Set your multimeter to the continuity mode

The continuity mode is the mode that can test if there is a complete circuit between two points. It usually has a diode symbol or a sound wave on the dial.

When you touch the probes of the multimeter to two issues connected by a circuit, the multimeter will beep or show a low resistance value on the display. If there is no circuit between the two points, the multimeter will not beep or offer a high resistance value on the show.

Test the touchpad with the multimeter

To test the touchpad, touch the multimeter probes to the pins on the ribbon connector and press the buttons. The pins on the ribbon connector correspond to the rows and columns of the matrix of the touchpad. You can refer to the electrical schematic of your microwave oven to determine which pins correspond to which buttons. You can also use a trial-and-error method by touching different combinations of hooks and pressing other buttons until you find a match.

When you feel the probes to the pins that correspond to control and demand that button, the multimeter should beep or show a low resistance value. It means the switch or the trace is faulty and must be replaced if it does not. If the multimeter beeps or offers a low resistance value for all the buttons, the touchpad works correctly, and the problem is likely with the control board.

Test the control board with the multimeter

To test the control board, you must carefully touch the provided multimeter probes to the terminals on the socket where the ribbon connector was plugged in and press the buttons on the touchpad. The terminals on the socket correspond to the pins on the ribbon connector and the buttons on the touchpad.

You can refer to the electrical schematic of your microwave oven to determine which terminals correspond to which buttons. You can also use a trial-and-error method by touching different combinations of terminals and pressing other buttons until you find a match. When you feel the probes to the terminals that correspond to a controller and demand that button, the multimeter should beep or show a low resistance value.

If it does not, the airport or the control board is faulty and needs to be replaced. Suppose the multimeter beeps or shows a low resistance value for all the buttons. In that case, the control board is working correctly, and the problem is likely with the ribbon connector or the connection between the touchpad and the control board.

How to Replace the Faulty Touchpad or the Control Board if Needed

If you have identified the faulty component, you must replace it with a new one. You can buy a new touchpad or control board from any appliance parts store or online. Ensure you buy the correct model and brand for your microwave oven, as they may vary in size, shape, and functionality.

Remove the old component

To remove the old touchpad, peel off the plastic layer that covers it and cut off the ribbon connector from the touchpad. Be careful not to damage the front panel or microwave oven display. To remove the old control board, you need to unscrew the screws that hold it in place and disconnect the wires that connect it to the microwave oven. Be careful not to pull or cut wires, and label them if necessary to reconnect them later.

Install the new component

To install the new touchpad, align the ribbon connector with the socket on the control board and gently push it in. Ensure the connector is firmly and correctly inserted, and there are no loose or bent pins. Then, you must stick the new touchpad’s plastic layer onto the microwave oven’s front panel and smooth out any wrinkles or bubbles. To install the new control board, you need to connect the wires to the terminals on the board and screw the board in place. Ensure the cables are securely and correctly connected and there are no loose or exposed wires.

Reassemble the microwave oven

To reassemble the microwave oven, reverse the steps you took to disassemble it. You need to reconnect the front panel to the microwave oven and screw it in place. Then, you need to slide the cabinet onto the microwave oven and screw it in place. Make sure there are no gaps or misalignments between the parts and there are no screws or wires left out.

How to Test the Microwave Oven for Functionality

After you have replaced the faulty component and reassembled the microwave oven, you need to test it for functionality. To do this, you need to follow these steps:

Plug the microwave oven into the power source and turn it on

The display should light up, and the touchpad should respond to your commands. If not, recheck the connections and the components and make sure everything is in place and working correctly.

Set the clock and the date on the microwave oven, if needed

This will help you keep track of the time and the cooking duration. To set the clock and the date, press the clock button on the touchpad and enter the current time and date using the number buttons. To confirm, press the clock button once more.

Test the essential functions of the microwave oven, such as the time, power level, and cooking mode

To test the time, you must enter a desired time using the number buttons and press the start button. The microwave oven should start heating, and the display should show the countdown. To test the power level, press the power button on the touchpad and select a desired power level using the number of buttons. The power level ranges from 1 to 10, with ten being the highest.

Press the cook button on the touchpad to test the cooking mode and select a desired one using the number buttons. The cooking mode varies depending on the model and brand of your microwave oven, but some common ones are defrost, reheat, popcorn, pizza, and sensor cook. The microwave oven should adjust the time and power level according to your selected cooking mode.

Test the advanced functions of the microwave oven, such as the timer, the child lock, and the sound

To test the timer, press the timer button on the touchpad and enter a desired time using the number buttons. Then, press the start button. The microwave oven should start counting down and beep when the time is up. Press and hold the stop/clear button to test the child lock for three seconds. The display should show a lock symbol, and the touchpad should be disabled.

Hold the stop/clear button for three seconds to unlock the touchpad. You must press and hold the 0 button to test the sound for three seconds. The display should show a sound symbol, and the microwave oven should beep when you press any button. To mute the sound, you must press and hold the 0 button for three seconds again.

If the microwave oven passes all the tests, you have successfully repaired the touchpad, and the microwave oven is ready to use. If the microwave oven fails any of the tests, there is still a problem with the touchpad, the control board, or another component, and you may need to consult a professional or buy a new microwave oven.

Conclusion

I believe that, without a doubt, you learned how to repair the L.G. microwave oven touchpad in these easy steps.

By carefully following this guide, you can repair your L.G. microwave oven touchpad and save money and time. You have also gained some basic knowledge of how microwave ovens work and how to troubleshoot them.

IAMJUSTINA

How to Repair LG Microwave Oven Touchpad

How a Microwave Oven Touchpad Works and Why It May Fail