How to Fix a Microwave Oven That Runs with the Door Open by Replacing a Faulty Door Switch

WeRmudfun

Summary:

This video demonstrates how to fix a microwave oven that runs with its fan on or displays other unusual behavior when the door is open, which is typically caused by a faulty door switch. The process involves:

• Ensuring safety by unplugging the microwave.
• Removing the top panel and control panel to access the internal components.
• Locating the three door switches, usually found behind the control panel.
• Identifying the faulty switch, which often won't produce an audible "click" when pressed.
• Disconnecting the wires and replacing the old switch with a new one.
• Reassembling the microwave by reversing the disassembly steps.
• Plugging the microwave back in and testing its functionality to ensure the fan no longer runs with the door open and regular cooking functions work correctly.

Introduction to the Microwave Problem [0:00]

The video addresses a common microwave issue where the fan turns on or the unit otherwise runs when the door is open. The host, Chuck, emphasizes that this indicates a problem, likely with one of the microwave's safety door switches.

• Safety Disclaimer: The video states it's not instructional and homeowners should proceed with caution and at their own risk. It highlights the importance of unplugging the microwave before starting any work.
• Microwave Model: The demonstration is performed on a Samsung microwave, but the principles generally apply to most microwave models with similar setups.

Disassembly of the Microwave [0:40]

To access the internal components and the door switches, specific parts of the microwave need to be carefully removed.

• Unplugging the Microwave: Crucially, always unplug the appliance before beginning any repair work to prevent electric shock. [0:44]
• Removing the Top Panel:
  • Two Phillips head screws located on the top of the microwave door frame need to be removed. [0:53]
  • Once screws are out, the panel needs to be slid to the left and then removed. [1:08]
• Removing the Control Panel:
  • One screw needs to be removed from the top of the control panel. [1:16]
  • The panel is then lifted up and pulled away to reveal the internal wiring and components. [1:28]
  • Behind the control panel, a bracket holds the door switches in place.
  • Torx bolts hold this bracket in place; these need to be unscrewed. [1:48]
  • The bracket then needs to be carefully worked out and lifted up from the back to remove it completely. [2:12]

    

Diagnosing the Faulty Door Switch [2:24]

The microwave in this model has three door switches, and a simple method can be used to identify the malfunctioning one.

• Locating the Switches: The three switches are arranged vertically within the bracket. [2:39]
• Testing by "Click" Sound:
  • A functional switch should produce a distinct "click" sound when its button is pressed. [2:31]
  • The faulty switch will not produce this click. [2:42]
  • While a multimeter can be used for precise testing, the "no click" method is a quick indicator of a bad switch.
• Previous Attempts to Fix: The host mentions he had previously tried to repair the switch by flattening a bent piece of metal inside, but this repair is temporary and doesn't last. [3:21]

  

  • The spring steel piece inside the switch prevents the two points from touching, completing the circuit. [3:51]
  • A bad switch often has a bent or overly arched spring steel piece, preventing the proper contact. [3:58]
  • Temporarily straightening this metal piece can make the switch work, but it's not a permanent solution. [4:00]

Replacing the Door Switch [4:30]

Replacing the faulty switch is a straightforward process once it's identified.

• Removing the Bad Switch:
  • Pull back on the lock mechanism of the switch. [2:53]
  • Pull the entire switch unit out of its housing. [2:59]
  • Disconnect the wires, noting which wire goes to which terminal (e.g., white on bottom, black on top). [3:03]
• Installing the New Switch:
  • Connect the wires to the new switch, ensuring they are placed on the correct terminals as noted during removal. [4:44]
  • Insert the new switch into the bracket, ensuring the button is forward and the back tab is held down. [4:35]
  • Push it in until it clicks and is securely locked in place. [4:38]
• Reinstalling the Switch Bracket:
  • The bracket has tabs that lock into slots on the microwave frame. [5:11]
  • Align the bracket, push it into place, and secure it with the Torx screws. [5:15]

Reassembly and Testing [5:49]

Once the new switch is installed, the microwave needs to be reassembled and its functionality verified.

• Reattaching the Control Panel:
  • Ensure all wires are neatly tucked away and secured by any clamps. [6:00]
  • Align the control panel's tabs into the corresponding slots on the microwave. [6:05]
  • Push the panel down until it's properly aligned, then reinsert the screw at the top. [6:10]
• Reattaching the Top Panel:
  • Align the tabs of the top panel into its slots. [6:32]
  • Push it all the way to the left, then slide it to the right to lock it in place. [6:42]
  • Reinsert the two Phillips head screws on the top. [6:48]
• Final Testing:
  • Plug the microwave back in. [7:01]
  • Reset the clock. [7:09]
  • Open and close the door multiple times to confirm the fan does not run. [7:21]
  • Place an item (like a cup of water) inside and run the microwave to ensure normal operation. [7:35]
  • Verify that the fan now only runs when the microwave is actually cooking and not when the door is open. [7:47]