Troubleshooting and Repairing a Faulty FPC Membrane Key Switch in a Microwave Oven (Part I)

Troubleshooting and Repairing a Faulty FPC Membrane Key Switch in a Microwave Oven (Part I)

When the keys on your microwave oven's FPC membrane key switch stop working, it can be frustrating. However, with a few simple checks and repairs, you can get your microwave back up and running in no time. In this article, we will discuss common issues that cause key failures and provide guidance on how to fix them.

1. Check for Loose Contacts:
First, ensure that the contacts inside the key switch are not loose. Pay close attention to the tin point. Additionally, check if the microwave door is closing properly, as loose connections may occur here. Tighten any loose fuses and inspect the keyboard input circuit and the single-chip microcomputer input port for any failures.

2. Understanding the Microwave Light Touch Membrane Switch:
The microwave light touch membrane switch operates as a 4x6 matrix switch. In its default state, when no key is pressed, the 10 lines between the rows and columns should not be connected. However, when a key is pressed, the corresponding row and column lines should connect. For example, pressing the cooking key should connect wires ① and ⑦.

3. Identifying Key Failure Causes:
There are several reasons why keys may fail on the membrane switch:
a. Bad tact switch: The tact switch may be faulty and require replacement.
b. Loose connection: Check for any loose connections between the tact switch and the connector.
c. Cracking and open circuit: Inspect the triode, resistor, and printed circuit for any cracks or open circuits.

4. Troubleshooting and Repairing:
After inspecting the tact switch, switch wiring, and peripheral components and finding no abnormalities, it is likely that the single-chip microcomputer is damaged. If only a few buttons are not working, it could be due to aging micro-buttons embedded inside, which can be replaced. These replacement buttons can often be found at a low price in miscellaneous electricity markets. However, if all buttons fail, it indicates a faulty internal computer board, requiring the replacement of the entire board.

By following the steps outlined in this article, you can diagnose and repair issues with a faulty FPC membrane key switch in your microwave oven. Remember to check for loose contacts, inspect the membrane switch's connections, and troubleshoot potential causes of key failures. With these tips, you can restore your microwave oven's functionality and enjoy hassle-free cooking once again.

LuphiTouch,a professional OEM manufacturer of user interface subassembly products.

^{Dongguan Luphi Electronics Technology Co., Ltd.(branded as LuphiTouch) was established in 2008. It located in Dongguan, China. The factory covers 4500 square meters. It close to Shenzhen, Guangzhou and Hongkong. To Shenzhen airport is just about 30 minutes and to Guangzhou Baiyun Airport is just about 1 hour. LuphiTouch is a high-tech enterprise for human machine interface assemblies.}

^{Our main business and products include designing and manufacturing various kinds of membrane switches, membrane keypads, graphic overlays, membrane circuits, backlighting membrane keypads like the LED backlighting membrane switches, EL backlighting membrane switches, LGF backlighting membrane switches, capacitive membrane switches, capacitive sensing circuits, printed touch sensors, capacitive font panels and nameplates, labels, PCBA, prototype to middle volume metal + plastic + electronics turnkey assembly projects.}

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Luphi Electronics has many strengths-we use high quality imported raw materials and have a skillful team of workers,as well as modern production and testing equipment,our facility is certified with ISO 9001,medical ISO13485,environmental ISO14001,health and safety ISO45001, and the production areas are equipped with 10000 and 1000 class cleanrooms.our products obtain main quality certificates for major markets, such as Europe,North America and Australia.

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