LG LSMC3089BD User manual

MICROWAVE OVEN
SERVICE MANUAL
MODEL: LSMC3086ST
LSMC3089BD
CAUTION
BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
Website http://biz.lgservice.com
P/NO : MFL06272539
May, 2015
Printed in Korea
삼흥
정판
Internal Use Only

CAUTION
WARNING TO SERVICE TECHNICIANS
PRECAUTIONS TO BE OBSERVED BEFORE AND
DURING SERVICING TO AVOID POSSIBLE EXPOSURE
TO EXCESSIVE MICROWAVE ENERGY
a. Do not operate or allow the oven to be operated with the door open.
b. Make the following safety checks on all ovens to be serviced before activating the
magnetron or other microwave source, and make repairs as necessary; (1) Interlock
operation, (2) proper door closing, (3) seal and sealing surfaces (arcing, wear, and other
damage), (4) damage to or loosening of hinges and latches, (5) evidence of dropping or
abuse.
c. Before turning on microwave power for any service test or inspection within
the microwave generating compartments, check the magnetron, wave guide or
transmission line, and cavity for proper alignment, integrity, and connections.
d. Any defective or misadjusted components in the interlock, monitor, door seal, and
microwave generation and transmission systems shall be repaired, replaced, or
adjusted by procedures described in this manual before the oven is released to the
owner.
e. A Microwave leakage check to verify compliance with the Federal performance standard
should be performed on each oven prior to release to the owner.
• Proper operation of the microwave ovens requires that the magnetron be assembled to the wave guide and cavity.
Never operate the magnetron unless it is properly installed.
• Be sure that the magnetron gasket is properly installed around the dome of the tube whenever installing the
magnetron.
• Routine service safety procedures should be exercised at all times.
• Untrained personnel should not attempt service without a thorough review of the test procedures and safety
information contained in this manual.

FOREWORD
Read this Manual carefully. Failure to adhere to or observe the information in this Manual may result in exposing
yourself to the Microwave Energy normally contained within the oven cavity.
TABLE OF CONTENTS
(Page)
SAFETY PRECAUTIONS ............................................................................................................. Inside front page
SPECIFICATIONS................................................................................................................................................ 1-1
CAUTIONS........................................................................................................................................................... 2-1
INSTALLATIONS ................................................................................................................................................. 3-1
OPERATING INSTRUCTIONS ............................................................................................................................ 4-1
CONTROL PANEL........................................................................................................................................... 4-1
CONTROL PANEL INSTRUCTIONS............................................................................................................... 4-2
OVERALL CIRCUIT DIAGRAM........................................................................................................................... 5-1
SCHEMATIC DIAGRAM.................................................................................................................................. 5-1
GENERAL INFORMATION FOR SERVICE......................................................................................................... 6-1
GENERAL PRECAUTIONS IN USE .............................................................................................................. 6-1
TRIAL OPERATION ........................................................................................................................................ 6-1
FEATURES AND SPECIFICATIONS FEATURES .......................................................................................... 6-1
SERVICE INFORMATION.................................................................................................................................... 7-1
PRECAUTIONS AND REPAIR SERVICE TIPS .............................................................................................. 7-1
MICROWAVE LEAKAGE TEST ...................................................................................................................... 7-2
POWER OUTPUT MEASUREMENT .............................................................................................................. 7-3
DISASSEMBLY INSTRUCTIONS ................................................................................................................... 7-4
INTERLOCK SYSTEM .................................................................................................................................. 7-11
INTERLOCK CONTINUITY TEST................................................................................................................. 7-13
TEST AND CHECKOUT PROCEDURES AND TROUBLESHOOTING........................................................ 7-14
A. TEST PROCEDURES ......................................................................................................................... 7-14
B. CHECKOUT PROCEDURES .............................................................................................................. 7-17
C. TROUBLESHOOTING......................................................................................................................... 7-20
EXPLODED VIEW................................................................................................................................................ 8-1

1-1
SPECIFICATIONS
Rated Power Consumption ................................ Microwave 1650W
Convection 1650W
Microwave Output............................................... Microwave 950W (IEC60705)
Adjustable 95W through 950W, 10 steps
Convection 1500W
Frequency .......................................................... 2450 MHz ±50 MHz
Power Supply .................................................... 120 V~ 60 Hz
Rated Current .................................................... Microwave 14.0A
Convection 14.0A
Magnetron Cooling ............................................ Forced Air Cooling
Rectification ....................................................... Rectification Voltage Double Half-Wave
Door Sealing ...................................................... Choke System
Safety Devices ................................................... Magnetron Thermostat: Open at 160 °C ± 5 °C
Close at 0 °C ± 5 °C
............................................................................ Oven Thermostat: Open at 145 °C ± 5 °C
Close at 0 °C ± 5 °C
............................................................................ Fuse(20A)
............................................................................ Primary Interlock Switch
............................................................................ Secondary Interlock Switch
............................................................................ Interlock Monitor Switch
Magnetron ......................................................... 2M246
Cook top Lamp .................................................. 130 V, 50 W
Cavity Lamp ....................................................... 130 V, 50 W
Timer ................................................................. Digital, up to 99 min. 99 sec. (in each cooking stage)
Tray ................................................................... Tempered Safety Glass
Overall Dimensions ........................................... 2915/16”(W)x167/16”(H)x153/8”(D)
Oven Cavity Size ............................................... 211/4”(W)x97/16”(H)x143/16”(D)
Effective Capacity of Oven Cavity ..................... 1.7 Cu.ft.
Accessories ....................................................... Use & Care Guide, Cooking Guide, Installation Manual
Exhaust Adapter, Exhaust Damper, Mounting Kit & Two Filter
Shaft, Rotating Ring, Glass Tray, Grill Rack, Metal Tray
SWITCH CHART
SWITCH MODE
PRIMARY
INTERLOCK
SWITCH
SECONDARY
INTERLOCK
SWITCH
INTERLOCK
MONITOR
SWITCH
CONDITIONS COM
NO
COM
NO
COM
NC
DOOR OPEN OPEN OPEN OPEN
DOOR CLOSED CLOSE CLOSE CLOSE
NOTE: Use the above switch chart with circuit diagram on page 5-1.

2-1
CAUTIONS
Unlike other appliances, the microwave oven is
high-voltage and high-current equipment.
Though it is free from danger in ordinary use,
extreme care should be taken during repair.
MICROWAVE RADIATION
Personnel should not be exposed to the
microwave energy which may radiate from the
magnetron or other microwave generating
device if it is improperly used or connection.
All input and output microwave connections,
waveguide, flange, and gasket must be secure
never operate the device without a microwave
energy absorbing load attached.
Never look into an open waveguide or antenna
while the device is energized.
• DO NOT operate on a 2-wire extension cord during repair
and use.
• NEVER TOUCH any oven components or wiring during
operation.
• BEFORE TOUCHING any parts of the oven, always
remove the power plug from the outlet.
• Remove your watches whenever working close to or
replacing the Magnetron.
• DO NOT touch any parts of the control panel circuit. A
resulting static electric discharge may damage this P.C.B.
• NEVER operate the oven with no load.
• NEVER injure the door seal and front plate of the oven
cavity.
• NEVER put iron tools on the magnetron.
• NEVER put anything into the latch hole and the interlock
switches area.
• Proper operation of the microwave oven requires that
the magnetron be assembled to the waveguide and
cavity. Never operate the magnetron unless it is
properly installed.
• Be sure that the magnetron gasket is properly
installed around the dome of the tube whenever
installing the magnetron.
THE OVEN IS TO BE SERVICED ONLY
BY PROPERLY QUALIFIED SERVICE
PERSONNEL.
Gasket
ANTENNA
COOLING FIN
MAGNETRON
CHASSIS GROUND FILAMENT
TERMINALS
MAGNETRON