LG Electronics MS3447GR Measurement of Microwave Power Output, Disassembly and Adjustment

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MEASUREMENT OF MICROWAVE POWER OUTPUT

•Microwave power output measurement is made with the microwave oven supplied at its rated voltage and operated at its maximum microwave power setting with a load of (1000±5) g of potable water.

•The water is contained in a cylindrical borosilicate glass vessel having a maximum material thickness of 3 mm and an outside diameter of approximately 190mm.

•The oven and the empty vessel are at ambient temperature prior to the start of the test.

•The initial temperature (T1) of the water is (10±2)°C. It is measured immediately before the water is added to the vessel. After addition of the water to the vessel, the load is immediately placed on the center of the turntable which is in thd lowest position and the microwave power switched on.

•The time T for the temperature of the water to rise by a value ∆ T of (10±2)°K is measured, where T is the time in seconds and ∆T is the temperature rise. The initial and final water temperatures are selected so that the maximum difference between the final water temperature and the ambient temperature is 5°K.

•The microwave power output P in watts is calculated from the following formula :

4187 x (∆T) + 0.55 X (T2 - T0 ) X M

P =

T

•T2: Temperature after heating

•T0: Temperature of bowl

•M: Weight of bowl

is measured while the microwave generator is operating at full power. Magnetron filament heat-up time is not included. (about 3 sec)

•The water is stirred to equalize temperature throughout the vessel, prior to measuring the final water temperature.

•Stirring devices and measuring instruments are selected in order to minimize addition or removal of heat.

DISASSEMBLY AND ADJUSTMENT

A. OUTER CASE REMOVAL

1)Disconnect the power supply cord from the outlet.

2)Remove the screws from the rear of the case.

The outer case must be moved backward to be lifted off.

B. POWER SUPPLY CORD

1)Remove the outer case.

2)Disconnect two terminals and remove one screw of the ground terminal.

C. CONTROL PANEL ASSEMBLY

1)Open the door.

2)Disconnect the lead wire from RELAY (RY2) of the

PCB SUB ASSEMBLY.

3)Disconnect the leadwire from connector (CN1) of the

PCB SUB ASSEMBLY.

4)Remove screw which hold the controller assembly to the cavity.

5)Lift up and pull out control panel assembly carefully from the cavity.

CAUTION: DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE SERVICING (refer to page 2-1)

Remove the screw

Lift up and pull out control panel

LGE Internal Use Only

5-3

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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