GE LMAB1240ST service manual Circuit Description

Page 11

CIRCUIT DESCRIPTION

GENERAL DETAILS

•The low voltage transformer supplies the necessary voltage to the micom controller when power cord is plugged in.

•When the door is closed, the primary switch is ON, the secondary switch is ON, and the monitor switch opens (contact COM and NO).

WHEN SELECTING COOKING POWER LEVEL AND TIME

•The micom controller memorizes the function you set.

•The time you set appears in the display window.

•Each indicator light turns on to indicate that the stage has been set.

WHEN TOUCHING THE START PAD

•The coil of the relay is energized by the micom controller.

•Power input is supplied to the high voltage transformer through the fuse to the primary switch and relay 2.

•Turntable rotates.

N

 

 

 

 

H.V.

 

MONITOR

TRANS-

 

FORMER

L

SWITCH

 

FUSE

PRIMARY

 

SECONDARY

SWITCH

RELAY 2

SWITCH

 

 

•A high voltage of approximately 2100 volts AC is generated in the secondary of the high voltage transformer which is increased by the action of the high voltage diode and charging of the high voltage capacitor.

•The negative 4,000 Volts DC is applied to the filament of the magnetron.

WHEN THE OVEN IS SET AT ANY LEVEL EXCEPT MAXIMUM.

•The micom controller controls the ON-OFF time of relay 2 by the applied signal to vary the average output power of microwave oven as POWER LEVEL.

(refer to page 1-1)

•One complete cycle of relay 2 is 22 seconds.

WHEN THE DOOR IS OPENED DURING COOKING

•Both the primary switch and relay 2 cut off the primary winding voltage of the high voltage transformer.

•ON-OFF of relay 2 is coupled electrically with opening and closing of the secondary switch.

•When the door is opened, the secondary switch is opened and when the door is closed, the secondary switch is closed.

•The cooking time stops counting down.

•Relay stops functioning.

•As the door is opened, if the contact of primary switch and relay 2 and/or secondary switch fail to open, the fuse opens due to the large current surge caused by the monitor switch activation, which in turn stops magnetron oscillation.

MICOM CONTROLLER

• The fan motor rotates and cools the magnetron by

blowing the air (coming from the intake on the

baseplate).

• The air is also directed into the oven to exhaust the

vapor in the oven through the upper plate.

• Cooking time starts counting down.

• 3.3 volts AC is generated from the filament winding of

the high voltage transformer. This 3.3 volts is applied to

the magnetron to heat the magnetron filament through

N

 

MONITOR

L

SWITCH

FUSE

PRIMARY

SWITCH RELAY 2

H.V.

TRANS-

FORMER

SECONDARY

SWITCH

two noise-preventing choke coils.

MICOM CONTROLLER

4-5

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Contents Microwave Oven Microwave Radiation Safety PrecautionsContents Description SpecificationsAntenna Microwave RadiationGrounding Instructions InstallationInstalling Control Panel FeaturesOperating Instructions Operating Sequence Schematic Diagram I *Check the Rating Model No Page Circuit Description Necessary Tools Service InformationTools and Measuring Instruments Microwave Leakage TestMeasurement with a Fully Assembled Oven Measurement with Outer Case RemovedControl Panel Assembly Measurement of Microwave Power OutputDisassembly and Adjustment Power Supply CordDoor Assembly Removal PCB Assembly RemovalVery Carefully Magnetron RemovalRemoving the Turntable Motor Iinterlock System FAN Motor Assembly RemovalHigh Voltage Transformer Removal High Voltage Capacitor and Diode RemovalSwitches Primary Interlock Switch TestSecondary Interlock Switch Test Monitor Switch TestMagnetron Component Test ProcedureFilament Winding Primary Terminal Diode High VoltageCapacitor FAN Motor PowerRelay LevelCondition Cause Remedy Trouble ShootingResult Result Condition Check Defective high voltage transformer Introduction Exploded ViewDoor Parts Control Panel Parts Oven Cavity Parts Larch Board Parts Model LMAB1240ST Interiot Parts56201A Base Plate Parts

LMAB1240ST specifications

The GE LMAB1240ST is a remarkable side-by-side refrigerator that embodies modern design and advanced technology, catering to the needs of today's consumers. Offering a perfect blend of style, functionality, and efficiency, this model stands out in the crowded marketplace.

One of the main features of the LMAB1240ST is its spacious interior. With a generous capacity of 24.9 cubic feet, this refrigerator provides ample storage for families and individuals alike. The side-by-side configuration allows easy access to both fresh and frozen foods, making organization simple and efficient.

In terms of cooling technology, the LMAB1240ST uses advanced climate control features. The refrigerator is equipped with a multi-air flow system that ensures consistent airflow throughout the unit. This technology helps maintain even temperatures, keeping food fresher for longer. Additionally, the adjustable shelves allow for customization of the interior space, accommodating various sizes of food items and containers.

The GE LMAB1240ST emphasizes energy efficiency as well. It is Energy Star certified, indicating that it meets or exceeds energy efficiency guidelines set by the U.S. Environmental Protection Agency. This not only helps reduce utility bills but also minimizes environmental impact, which is a consideration for eco-conscious consumers.

Another significant feature of this model is its water and ice dispenser. The dispenser is designed to provide chilled water and cubed/crushed ice right at your fingertips. It is conveniently located on the front of the refrigerator for easy access. The filter system ensures that the water dispensed is clean and free from contaminants, enhancing safety and taste.

Additionally, the LMAB1240ST boasts advanced convenience features such as LED lighting, which provides bright and energy-efficient illumination within the refrigerator and freezer compartments. The easy-to-use temperature controls allow users to adjust settings effortlessly, ensuring optimal conditions for food storage.

Lastly, the stainless steel finish of the GE LMAB1240ST not only adds a sleek and contemporary look but also resists fingerprints and smudges, making maintenance more manageable. With a combination of innovative features, energy efficiency, and stylish aesthetics, the GE LMAB1240ST is an exceptional choice for anyone looking to upgrade their kitchen appliance.
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