Microwave oven repair Nairobi

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MICROWAVE OVEN REPAIR
Microwae oven parts, microwave oven faults and error diagnosis, microwave oven repair and maintenance, microwave oven services

Microwave oven Membrane Switch
If the touch pads on your microwave oven do not respond but the display lights up, the problem is most likely with the membrane switch. This component, which is more commonly referred to as the touch pad, is actually a series of soft touch electrical switches.

It is usually made up of two layers of a thin Mylar plastic with a conductive material on the inner surfaces. A formed gap between the two surfaces will separate the conductive coatings until pressure is applied by the user, making the two surfaces come in contact. When the two conductive surfaces contact each other, an electrical circuit is completed to provide an input signal to the control board.

With repeated use, the conductive coating will eventually wear out and be unable to make a good enough contact to send the signal to the control board. To access the membrane switch you will need to unplug the unit and remove the cabinet. The membrane switch is often attached to the control panel and is usually connected to the electronic control board with a flat ribbon style connector.

Check the connection first and if it appears okay, then you can test the membrane switch for continuity with a multi-meter. There should only be a few ohms of resistance for each touch pad when pressed. To perform this test you will require the matrix layout of the membrane switch which should be contained in the electrical schematic.

microwave oven repair nairobi-mombasa-nakuru-kenyaMicrowave oven Control Board
If the touch pads on your microwave oven do not respond but the display lights up, the problem may be with the control board. The control board generates a low voltage that is supplied to the membrane switch.

When a pad is depressed, the voltage signal is switched back to the control board. The control board receives these input signals from the membrane switch or touch pad and uses these commands to turn on output relays that control the various components of the microwave, such as the turntable motor and the magnetron.

If the control board does not generate the low voltage signal, or if it does not sense the input signals from the membrane switch, then no output functions will occur.

If you have verified that the membrane switch is fine and the connection to the control board is okay, then the control board may be defective. Replacement will require disconnecting the power and removal of the cabinet and control assembly.

best nairobi plumber plumbing services in kenyaMicrowave oven Drive Motor
If the turntable on your microwave is making an unusual noise, the problem may be with the drive motor. Most microwave ovens with a glass tray use a motor driven coupler to turn the tray or a roller guide.

The motor is typically located below the floor of the oven, and access will need to be through the bottom. The motor is normally held in place with a retaining screw and will have two wires attached to it as well. If the motor is making a grinding noise it will need to be replaced.

Microwave oven Magnetron
If your microwave is making an unusual or loud humming noise, you may have a problem with the magnetron. This component is part of the high voltage circuit and provides the microwaves that generate the heat. If the magnetron is defective, it may cause a loud humming or buzzing noise.

Access to the magnetron will require removal of the cabinet. Disconnect the power and also discharge the high voltage capacitor to prevent an electrical shock. You can then locate the magnetron and disconnect the two attached wires and the mounting screws to remove it.

You should also check the high voltage diode to verify that it is not shorted before condemning the magnetron.

Microwave oven Drive Coupler
If your microwave is making an unusual noise, the problem may be with the drive coupler for the turn tray. Most microwave ovens with a round glass tray use a motor driven coupler to rotate the tray on a roller guide.

Some models that use a rectangular tray will have a drive coupler that has an offset center roller to drive the tray guide from side to side.

For either style, remove the tray and roller guide from the oven and then inspect the coupler. Some models may require you to remove the motor from the bottom before you can pull the coupler off of the motor. The coupler normally has a D shaped opening that fits tightly onto the motor shaft.

If it is cracked or worn it may become noisy and will need to be replaced. If you have to remove the bottom cover, you will need to disconnect power from the appliance first.

Microwave oven Roller Guide
If your microwave is making an unusual noise when the turn tray is rotating, the problem may be with the roller guide under the tray. Some microwave ovens with a round glass tray use a motor driven coupler to turn the roller guide.

The roller guide is used to support the tray and to engage the rotating coupler. Remove the tray and then inspect the roller guide. Check the hub to see if it engages the coupler securely and also the outer rollers for signs of cracks or damage. If there are signs of wear or damage, it should be replaced.

Other models may just use the roller guide to support the tray, however the roller wheels may be damaged or worn and causing an unusual noise. If the roller guide appears to be normal, then check the coupler for damage.

Microwave oven High Voltage Diode
If your microwave is making an unusual or loud humming noise, you may have a problem with the high voltage diode. This component is part of the high voltage circuit along with the capacitor and the magnetron.

Access to the diode will require removal of the cabinet. Disconnect the power and also discharge the high voltage capacitor to prevent an electrical shock. You can then locate the diode and use a multi-meter to check for continuity.

Reverse the meter leads to check for continuity in the opposite direction. There should be continuity in only one direction and if not, it will have to be replaced.
 
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