LG LMVM2075SB User manual

삼흥
정판
MICROWAVE OVEN
SERVICE MANUAL
MODEL: LMVM2075SB
LMVM2075ST
LMVM2075SW
CAUTION
BEFORE SERVICING THE UNIT, READ THE
SAFETY PRECAUTIONS IN THIS MANUAL.
Website: http://us.lgservice.com
P/NO : MFL06272503
February, 2007
Printed in Korea

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
MATRIX CIRCUIT FOR TOUCH KEY BOARD ..............................................................................................5-2
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 ..................................................................................................................................7-12
INTERLOCK CONTINUITY TEST ................................................................................................................7-14
TEST AND CHECKOUT PROCEDURES AND TROUBLESHOOTING .......................................................7-15
A.TEST PROCEDURES ........................................................................................................................7-15
B.CHECKOUT PROCEDURES .............................................................................................................7-19
C.TROUBLESHOOTING .......................................................................................................................7-22
EXPLODED VIEW ..................................................................................................................................................8-1
PART REFERENCE LIST .......................................................................................................................................9-1

1-1
SPECIFICATIONS
Rated Power Consumption ................................1700W maximum (Microwave oven+Cook top lamps+Ventilation fan)
Microwave Output ...............................................1100W (IEC60705)
Frequency ..........................................................2450 MHz ±50 MHz
Power Supply .....................................................120 VAC, 60 Hz
Rated Current ....................................................14.5 Amp. (Microwave oven+Cook top lamps+Ventilation fan)
Magnetron Cooling .............................................Forced Air Cooling
Rectification .......................................................Rectification Voltage Double Half-Wave
Door Sealing ......................................................Choke System
Safety Devices ...................................................Magnetron Thermostat: Open at 145 °C ±5 °C
Close at 60 °C ±5 °C
............................................................................Oven Thermostat: Open at 110 °C ±5 °C
Close at 0 °C ±5 °C
............................................................................Fuse(20A)
............................................................................Primary Interlock Switch
............................................................................Secondary Interlock Switch
............................................................................Interlock Monitor Switch
Magnetron ..........................................................2M282J (Toshiba)
Cook top Lamp ...................................................12 VAC, 20 W (Halogen)
Cavity Lamp .......................................................125 V, 30 W or 40 W
Timer ..................................................................Digital,up to 99 min.(in each cooking stage)
Tray ....................................................................Tempered Safety Glass
Overall Dimensions ............................................2915/16”(W)x167/16”(H)x155/8”(D)
Oven Cavity Size ...............................................231/2”(W)x10”(H)x141/2”(D)
Effective Capacity of Oven Cavity ......................2.0 Cu.ft.
Accessories ........................................................Owner ’s Manual &Cooking Guide, Installation Manual,
............................................................................Exhaust Adapter, Exhaust Damper, Mounting Kit and Filter,
............................................................................Rotating Ring Assembly, Glass Tray, Metal Rack, Guide Tray,
............................................................................Defrosting (Melting/Softening) Racking.
SWITCH CHART
SWITCH MODE
CONDITIONS
DOOR OPEN OPEN OPEN CLOSE
CLOSE CLOSE OPEN
DOOR CLOSED
PRIMARY
INTERLOCK
SWITCH
SECONDARY
INTERLOCK
SWITCH
INTERLOCK
MONITOR
SWITCH
COM
NO
COM
NO
COM
NC
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.

3-1
INSTALLATIONS
BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY.
PRECAUTIONS ON INSTALLATION
A. Plug the power supply cord into a 120V AC, 60Hz,
single-phase power source with a capacity of at
least 20 amperes.
B. Avoid placing the unit in a location where there is
direct heat or splashing water.
C. Install the unit on the mounting plate firmly.
D. Place the unit as far away as possible from TV,
radio, etc. to prevent interference.
GROUNDING INSTRUCTIONS
For personal safety, this appliance must be fully
grounded at all times.
In the event of an electrical short circuit, grounding
reduces the risk of electrical shock.
The plug must be plugged into an outlet that is
properly installed and grounded.
CAUTION
This unit is equipped with a 3-prong plug for your
safety.If the wall outlet is a grounded 3-hole type,
the unit will be grounded automatically.
WARNING
Improper use of the grounding plug can result in a
risk of electric shock.
Do not, under any circumstances, cut or remove the
third ground prong from the power cord plug.

4-1
OPERATING INSTRUCTIONS
CONTROL PANEL
14 16
27
24
22
1917
12
15
18 20 21 23 26
25
13
11
10 1
6
9
8
7
3
5
4
2

4-2
CONTROL PANEL INSTRUCTIONS
1. DISPLAY: The Display includes a clock and indicators to tell
you time of day, cooking time setting, and cooking functions
selected.
2. SOFTEN: Touch this pad to soften Butter, Ice Cream,
Cream Cheese, and Frozen Juice.
3. MELT: Touch this pad to melt Butter / Magarine, Chocolate,
Cheese, and Marshmallows.
4. COOK: Touch this pad to cook Baked Potato, Vegetable
Casserole, Rice, and Frozen Entrée. The oven’s sensor will
tell the oven how long to cook depending on the amount of
humidity coming from the food.
5. REHEAT: Touch this pad to reheat Pizza Slice, Dinner
Plate, Soup/Sauce, and Casserole. The oven’s sensor will
tell the oven how long to cook depending on the amount of
humidity coming from the food.
6. POPCORN: Touch this pad when popping popcorn in your
microwave oven. The oven’s sensor will tell the oven how
long to cook depending on the amount of humidity it detects
from the popcorn.
7. AUTO DEFROST: Meat, poultry, fish, and bread. Touch this
pad to select food type and defrost food by weight.
8. TIME DEFROST: Touch this pad to defrost most other
frozen foods.
9. QUICK DEFROST: This pad provides quick defrost for 1.0
pound of frozen food.
10. CHICKEN CHOICES: Touch this pad to cook chicken
wings, chicken nugget, spicy chicken, and Mexican chicken.
11. HOLD WARM: Touch this pad to keep hot, cooked foods
warm in your microwave oven for up to 90 minutes.
12. EZ-ON: Touch this pad to set and start quickly at 100%
power level.
13. CUSTOM SET: Touch this pad to change the oven’s default
setting for sound, clock, disply speed, and defrost weight.
14. CLOCK: Touch this pad to enter the time of day.
15. CUSTOM COOK: Touch this pad to recall one cooking
instruction previously programmed into memory.
16. TIMER: Touch this pad to set the timer.
17. COOK TIME: Touch this pad to to set a cooking time.
18. POWER LEVEL: Touch this pad to select a cooking power
level.
19. MORE: Touch this pad to add ten seconds of cooking time
each time you press it.
20. LESS: Touch this pad to subtract ten seconds of cooking
time each time you press it.
21. NUMBER: Touch number pads to enter cooking time,
power level, quantities, or weights.
22. START/ENTER: Touch this pad to start a function. If you
open the door after oven begins to cook, touch
START/ENTER again.
23. STOP/CLEAR: Touch this pad to stop the oven or to clear
all entries.
24. VENT ON/OFF: Touch this pad to turn the fan on/off.
25. VENT 5-SPEED: Touch this pad to choose one of 5 fan
speeds.
26. VENT AUTO TIME SET: Touch this pad when setting
ventilation time. (1, 3, 5, 10, and 30 minutes.)
27. LIGHT HI/LOW/OFF: Touch this pad to turn the light on
high, low, or off.

5-1
OVERALL CIRCUIT DIAGRAM
SCHEMATIC DIAGRAM

5-2
MATRIX CIRCUIT FOR TOUCH KEY BOARD
VENT
5-SPEED
POPCORN
VENT
ON/OFF
1
N.C
CLOCK
WARM
STOP/
N.C CLEAR ENTER
START/
REHEAT
HI/LOW/OFF
COOK
HOLD
LIGHT
AUTO
DEFROST
890
TIME
DEFROST
MORE
SOFTEN
LESS
MELT
COOK
TIME
23
N.C
4
N.C N.C
56
N.C
7
CHICKEN
CHOICES
CUSTOM
SET N.C
POWER
LEVEL
AUTO
TIME SET
EZ-ON QUICK
DEFROST
TIMER
CUSTOM
COOK
KEY MATRIX
9
13
12
11
10
8
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