LG Electronics MS3447GRS Defective PCB assembly Defective high voltage transformer

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(TROUBLE 5) No microwave oscillation even though oven lamp and fan motor run. (Display operates properly)

CONDITION

No microwave oscillation.

CHECK

RESULT

Disconnect the

No continuity.

wire leads from

 

relay 2 and

 

check continuity

Continuity.

of relay 2.

 

(Operate the unit)

 

Check high vol-

Abnormal

tage transformer

 

Normal

CAUSE

Defective PCB assembly

Defective high voltage transformer.

REMEDY

Replace PCB assembly

Replace high voltage transformer.

Check high vol-

Abnormal

Defective high

tage capacitor

voltage capacitor.

 

 

Normal

 

Check high vol-

Abnormal

Defective high

tage diode

voltage diode.

 

 

Normal

 

Check

Abnormal

Defective

magnetron.

magnetron.

 

Replace high voltage capacitor.

Replace high voltage diode.

Replace magnetron.

NOTE : • Make sure the wire leads correct position.

•When Removing the wire leads from the parts, be sure to grasp the connector, not the wires.

•When removing the magnetron, be sure to install the magnetron gasket in the correct position and in good condition.

Output is full power when you set lower power level.

Disconnect the wire leads from relay 2 and check continuity relay 2. (Operate the unit)

Abnormal.

Defective PCB assembly.

Replace PCB assembly.

LGE Internal Use Only

5-15

Copyright © 2007 LG Electronics. Inc. All right reserved.

 

 

Only for training and service purposes

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Contents Microwave Oven Microwave Radiation Safety PrecautionsContents Full power throughout the cooking time SpecificationsApprox % of Full power Approx %Antenna Microwave RadiationInstalling InstallationEarthing Instructions Operating Instructions Features Control PanelMore Pressing More will add 10 seconds to the cooking time Cooking timeOperating Sequence Schematic Diagram Circuit Description Tools and Measuring Instruments Service InformationMicrowave Leakage Test Necessary ToolsMeasurement with a Fully Assembled Oven Measurement with Outer Case RemovedAround the magnetron Waveguide Disassembly and Adjustment Measurement of Microwave Power OutputPower Supply Cord Control Panel AssemblyDoor Main Assembly Removal PCB Assembly RemovalMagnetron Removal AIR Duct Assembly RemovalRemoving the Turntable Motor Very CarefullyHigh Voltage Transformer Removal FAN Motor Assembly RemovalHigh Voltage Capacitor and Diode Removal Interlock SystemSecondary Interlock Switch Test Primary Interlock Switch TestMonitor Switch Test SwitchesHigh Voltage Transformer Wire leads removed Component Test ProcedureFilament Winding Primary Terminal MagnetronMeasure the resistance Normal Momentarily indicates High VoltageCapacitor Measure the continuity Forward Normal ContinuityRelay PowerLevel FAN MotorCondition Cause Remedy Trouble ShootingDefective key membrane assembly Defective PCB assembly Defective PCB assemblySome inputs cannot be programmed Continuity No continuityPower supply Check continuity Continuity Monitor Switch with Door closedReplace power supply cord Fuse blowsSecondary switch Setting time Check continuityDefective PCB Replace PCB Assembly Power source Rating voltage Voltage Normal DisconnectAbnormal Defective PCB assembly Defective PCB assembly Defective high voltage transformerReplace high voltage diode Replace magnetron Introduction Exploded ViewDoor Parts Control Panel Parts Oven Cavity Parts Larch Board Parts WTT021 WTP004 56501A 54974T Interior PartsBase Plate Parts

MS3447GR, MS3447GRS specifications

The LG Electronics MS3447GRS and MS3447GR are innovative microwave models designed to enhance your cooking experience with a blend of advanced technology and user-friendly features. Both models are built to accommodate various culinary needs, making them ideal for any kitchen.

One standout feature of the MS3447GRS and MS3447GR is the Smart Inverter technology. This technology provides precise cooking power control, allowing users to defrost, reheat, and cook food evenly. This results in better texture and flavor retention in various dishes, surpassing traditional microwaves that may only provide two or three levels of heating.

Another significant characteristic is the EasyClean interior. This feature ensures that maintaining a clean microwave is hassle-free. The interior surface can be wiped down easily, helping to prevent the buildup of food residues and odors, which allows for a more hygienic cooking environment over time.

The LG MS3447GRS and MS3447GR also come equipped with a range of auto-cook options. These preset cooking modes simplify meal preparation, allowing users to cook a variety of dishes such as popcorn, baked potatoes, and frozen meals with just the push of a button. This is particularly beneficial for busy individuals and families looking to streamline their cooking process.

Additionally, these models boast a sleek and modern design that seamlessly integrates into any kitchen decor. The clean lines, polished finishes, and intuitive control panel make it an attractive and functional appliance. The user interface is designed for ease of use, with clear indicators and a layout that simplifies operation.

Both microwaves feature a spacious interior, which provides ample room for a variety of cookware sizes, making it easier to heat larger dishes. The turntable ensures that food is cooked evenly, while the powerful wattage guarantees efficient cooking times.

In conclusion, the LG Electronics MS3447GRS and MS3447GR microwave models are exemplary devices that combine cutting-edge technology with practical features. Their Smart Inverter, EasyClean technology, and flexible cooking options cater to the needs of modern kitchens, affirming LG's commitment to innovation and quality in kitchen appliances. Whether you're reheating leftovers or preparing a family meal, these microwaves make cooking simpler and more efficient.
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