LG Electronics LMV1825SBQ, MV1825SW Precautions and Repair Service Tips, Preliminary

Page 12

SERVICE INFORMATION

PRECAUTIONS AND REPAIR SERVICE TIPS

PRELIMINARY

A.SINCE NEARLY 2,100 VOLTS EXISTS IN SOME CIRCUITS OF THIS UNIT REPAIRS SHOULD BE CARRIED OUT WITH GREAT CARE.

The filament leads of magnetron carry High Voltage with respect to ground. Extreme caution must be exercised. Never plug the unit into a power source to determine which component is defective in high voltage section.

B.TO AVOID POSSIBLE EXPOSURE TO MICROWAVE ENERGY LEAKAGE, THE FOLLOWING PRECAUTIONS MUST BE TAKEN BEFORE SERVICING.

(1)Before the power is applied:

(a)Make sure the primary interlock switch, the secondary interlock switch and the interlock monitor switch operate properly by opening and closing the door several by opening and closing the door several times.

(b)Make sure the perforated screen and the dielectric choke of the door are correctly and firmly mounted.

(2)After power is applied:

(a)Make sure the interlock switch mechanism is operating properly by opening and closing the door.

(b)Check microwave energy leakage must bebelow the limit of 5 mW/cm2.

(All service adjustments should be made for minimum microwave energy leakage readings).

(3)Do not operate the unit until it is completely repaired, if any of the following conditions exist. The unit must not be operated.

(a)The door does not close firmly.

(b)The hinge is broken.

(c)The door seal is damaged.

(d)The door is bent or warped, or there is any other visible damage on the unit that may cause microwave energy leakage.

NOTE: Always keep the seal clean.

(e)Make sure that there are no defective parts in the interlock mechanism.

(f)Make sure that there are no detective parts

in the microwave generating and transmission assembly (especially waveguide).

(4)The following items should be checked after the unit is repaired:

(a)The interlock monitor switch is connected correctly and firmly.

(b)The magnetron gasket is properly positioned and mounted.

(c)The waveguide and the oven cavity are intact. (no microwave energy leakage)

(d)The door can be properly closed and the safety switches work properly.

(e)The unit must stop when the door is opened or the time is up.

The unit must not be operated with any of the above components removed or by-passed.

7-1

Image 12
Contents Safety Precautions in this Manual Microwave OvenPage Table of Contents Specifications Microwave Radiation Installation Grounding InstructionsOperating Instructions Control PanelControl Panel Instructions Overall Circuit Diagram Schematic DiagramMatrix Circuit for Touch KEY Board General Precautions in USE Features and Specifications FeaturesTrial Operation Precautions and Repair Service Tips PreliminaryMicrowave Leakage Test EquipmentPower Output Measurement Measurement with the Outer Case RemovedDisassembly Instructions Important NotesHOW to Remove the F.P.C. Connector HOW to Insert the F.P.C. ConnectorRemoving the OUT CASEFigure Removing the Door Interlock Switches Figures 9,10 Removing Magnetron Removing Stirrer FAN Removing Door FigureAssembling Door Removing the Ventilation MotorReplacing the Humidity Sensor Removing the Turntable Motor Interlock System Interlock MechanismTest the Latch and Switch Sequence Components Test Procedure Results Interlock Continuity TestTest and Checkout PROCEDURES, and Trouble Shooting Test ProceduresHIGH-VOLTAGE Diode FPC Connector Checkout Procedures Power LevelCheckout Procedures for Relay Problem a Checkout Procedures for Circuit Board Trouble Shooting Circuit board Poor Check the contact of relay 2see Normal Operation Circuit board Fuse Exploded View Control Panel Oven Cavity Latch Board Interior 50FZZA Installation Schematic Diagram of P.C.B Printed Circuit Board May