LG LMV1683ST User manual

삼흥
정판
MICROWAVE OVEN
SERVICE MANUAL
MODEL: LMV1683ST
LMV1683SB
LMV1683SW
CAUTION
BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
P/NO : MFL30474304
March, 2012
Printed in Korea
Website: http://biz.lgservice.com
삼흥
정판
Internal Use Only

-2-
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.
CONTENTS
(Page)
Safety Precautions .............................................................................................................................................. 2
1. Specification .................................................................................................................................................... 4
2. Cautions ........................................................................................................................................................... 5
3. Installation ....................................................................................................................................................... 6
4. Operation ......................................................................................................................................................... 7
4-1. Control Panel Features .............................................................................................................................. 7
4-2. Explanation of Control Panel...................................................................................................................... 8
5. Wiring Diagram / Key Matrix........................................................................................................................... 9
5-1. Wiring Diagram .......................................................................................................................................... 9
5-2. Key Matrix ............................................................................................................................................... 10
6. Troubleshooting ............................................................................................................................................ 11
6-1. General Information for Service ............................................................................................................... 11
6-2. Safety Caution.......................................................................................................................................... 12
6-3. Basic Check Summary............................................................................................................................. 13
6-4. Troubleshooting ....................................................................................................................................... 14
7. Microwave Leakage Test .............................................................................................................................. 25
8. Power Output Measurement......................................................................................................................... 27
9. Interlock System............................................................................................................................................ 28
9-1. Interlock Mechanism ................................................................................................................................ 28
9-2. Interlock Continuity Test........................................................................................................................... 30
10. Component Testing Information................................................................................................................ 31
11. Disassembly Instructions........................................................................................................................... 35
12. Exploded View ............................................................................................................................................. 42
-3-

-4-
1. SPECIFICATIONS
Rated Power Consumption ................................ 1500W maximum (Microwave oven+Cook top lamps+Ventilation fan)
Microwave Output ............................................... 1000W (IEC60705)
Frequency .......................................................... 2450 MHz ±50 MHz
Power Supply ..................................................... 120 VAC, 60 Hz
Rated Current .................................................... 14 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 ................................................... Oven Thermostat: Open at 90 °C ± 5 °C
Close at 0 °C ± 5 °C
............................................................................ Fuse (20A)
............................................................................ Primary Interlock Switch
............................................................................ Secondary Interlock Switch
............................................................................ Interlock Monitor Switch
Magnetron .......................................................... 2M214 - 161GP
Cook top Lamp ................................................... 125 V, 30 W or 40 W
Cavity Lamp ....................................................... 125 V, 30 W or 40 W
Timer .................................................................. Digital, up to 99 min. 99 sec. (in each cooking stage)
Tray .................................................................... Tempered Safety Glass
Overall Dimensions ............................................ 2915/16” (W) x 167/16” (H) x 1615/16” (D)
Oven Cavity Size ............................................... 219/16” (W) x 141/8” (H) x 83/4” (D)
Effective Capacity of Oven Cavity ...................... 1.6 Cu.ft.
Accessories ........................................................ Owner’s Manual & Cooking Guide, Installation Manual,
............................................................................ Exhaust Adapter, Exhaust Damper, Mounting Kit and Filter,
............................................................................ Glass Tray, Metal Rack, Rotating Ring Assembly.
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.

-5-
2. 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

-6-
3. INSTALLATION
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.

-7-
4. OPERATION
4-1. Control Panel
24
11
10
3
1
8
12
9
15
18
19
17
14
20
13
16
7
6
5

-8-
4-2. Explanation of Control Panel
1. DISPLAY The Display includes a clock and
indicators to tell you time of day, cooking time
settings and cooking unctions selected.
2. POPCORN Touch this pad when popping popcorn
in your microwave oven.
3. POTATO Touch this pad when roasting potato in
your microwave oven.
4. PIZZA Touch this pad when roasting pizza in your
microwave oven.
5. FROZEN ENTREE Touch this pad to select
frozen entree.
6. AUTO COOK Touch this pad to cook fresh
vegetable, frozen vegetable, rice, or casseroles.
7. AUTO REHEAT Touch this pad to reheat dinner
plate, soup/sauce, casserole, roll/muffin.
8. SOFTEN Touch this pad to soften butter, ice
cream, cream cheese, frozen juice.
9. MELT Touch this pad to melt butter or margarine,
chocolate, cheese, marshmallow.
10. AUTO DEFROST Meat, poultry, fish. Touch this
pad to select food type and defrost food by
weight.
11. TIME DEFROST This pad provides you with the
RAPID defrosting method for 1.0 pound frozen
foods.
12. TIME Touch this pad to set a cooking time.
13. CLOCK Touch this pad to enter the time of day.
14. POWER LEVEL Touch this pad to select a
cooking power level.
15. NUMBER Touch number pads to enter cooking
time, power level, quantities or weights.
16. START/ENTER Touch this pad to start a
function. If you open the door after oven begins
to cook, retouch START/ENTER.
17. STOP/CLEAR Touch this pad to stop the oven
or clear all entries.
18. LIGHT ON/OFF Touch this pad to turn the
cooktop/countertop light on or off.
19. VENT HI/LOW/OFF Touch this pad to turn the
Vent on or off.
20. ADD 30 SEC Touch this pad to control the add
30sec. cook time.

-9-
5. WIRING DIAGRAM / KEY MATRIX
5-1. Wiring Diagram

-10-
5-2. Key Matrix
KEY MATRIX

-11-
6. TROUBLESHOOTING
6-1. General Information for Service
GENERAL PRECAUTIONS IN USE
A. Never operate the unit when it is empty.
Operating the oven with no load may shorten the
life of the magnetron. Whenever cooking dry
foods (dried fish, bread, etc.)or a small amount of
food,
be sure to put a glass of water into the cooking
compartment. The glass turntable may become
hot after operating, be careful when touching it.
B. Aluminum foil should be avoided because it will
disrupt cooking and may cause arcing. However,
small pieces may be used to cover some parts of
food to slow the cooking. Any aluminum foil used
should never be closer than 2.5 cm to any side
wall of the oven.
TRIAL OPERATION
After installation, the following sequences and
results should be checked carefully.
A. Put a container filled with water (about 1 liter)into
the oven, and close the door tightly.
B. Set cooking time for 10 minutes by touching 1 and
then 0three times. 1, 0, 0, 0 appears in the
display window.
C. Touch the START key.
Make sure the cavity light comes on. The unit will
begin cooking and the display window will show
the time counting down by seconds.
D. After about 5 minutes, make sure the primary
interlock switch, the secondary interlock switch
and the interlock monitor switch operate properly
by opening and closing the door several times.
Touch the START key each time the door is
closed.
E. Continue operating the unit. Two short and a long
beep sound signal is heard when the time is up.
The unit will shut off automatically.
F. Confirm the water is hot.
G. Finally, measure the output power according to
POWER OUTPUT MEASUREMENT on
page 8.
FEATURES AND SPECIFICATIONS
FEATURES
A. The safety systems incorporated in this model
are:
(1) Primary interlock switch
(2) Secondary interlock switch
(3) Interlock monitor switch
(4) Choke system
(5) Oven cavity thermostat
(Note This thermostat located on the oven
cavity will open and stop the unit from
operation only if a high temperature is
reached, such as, a fire created by
overcooking food.)
B. Any one of 10 power output levels ranging 0 W to
1,000 W can be selected by the touch control and
electronic computer system.
C. Cooking time can be displayed on the digital
readout.
D. Three different cooking stages (Include Defrost)
can be changes from one cooking stage to
another. This is made possible with the memory
function of the microprocessor.

-12-
A. SINCE NEARLY 4,000 VOLTS EXISTS IN
SOME CIRCUITS OF THIS UNIT REPAIRS
SHOULD BECARRIED 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 be
below
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 bypassed.
6-2. Safety Caution

-13-
6-3. Basic Check Summary
Symptom: Dead
Check: Open/Short
Symptom#1(Door is closed): No
cook, Not operate F.M,S.M,T.T.M.
Check: Open/Short when the door
is closed. (Switch)
Symptom #2(Door is open):
Operating F.M, S.M, T.T.M.
automatically
Check: Open/Short when the door
is open. (Switch)
Symptom #1(Door is closed): No
key, Not start, Operating O.L, F.M,
S.M, T.T.M.
Check: Open/Short when the door
is closed. (Switch)
Symptom #2(Door is open): Not
turn on O.L
Check: Open/Short when the door
is open. (Switch)

-14-
6-4. Troubleshooting
No Display or Dead

-15-
6
3
4
1When you push the any Key,
is there any beep sound?
Does the display operate?
No
Yes
No
2Is the connector connected
to PCB?
Power Off
No
Yes
Reconnect or
repair the
connector.
Is there any beep sound in
continuity test between the
power code and connector ?
- Code “L” to Pin1
- Code “N” to Pin3
No
Yes
Check PCB
Go to No. 6 of
This flow chart.
Go to No. 6 of
this flow chart.
Is there any beep sound in
continuity test between the
ends of fuse?
Yes
No Replace the
Fuse.
5Is there any beep sound in
continuity test between the
ends of the noise filter?
Yes
No Replace the
Noise filter.
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
Replace the PCB.
(EBR67471707)
L

-16-
Keypad Failure

-17-
5
6
1Do not only START key and
EZ-ON key operate?
(Door should be closed.)
Does the keys operate?
No
Yes
No
2Is there beep sound
in continuity test between
the ends of latch board?
- Secondary switch
(Door should be closed.)
Power ON
Yes
No Adjust latch
board
(Refer to 9-1,
9-2)
Check PWB
Go to No. 5 of
this flow chart.
3When the door is opened,
is the voltage of door
sensing part over 4 V?
(CN3 Pin1 and Pin2)
Yes
No
Replace the PCB
(EBR67471707)
Reconnect or
repair the
connector.
Replace the PCB.
(EBR67471707)
4Is the connector connected
to PCB disconnected or
disassembled?
No
Yes
Replace the keypad?
No

-18-
No Heat / No Cook

-19-
1Repeat Door Open and close
more than three times.
Does product operate?
After power on, does the
product operate?
No
No
Yes
2Is there any beep sound
in continuity test between
TAB1 and TAB2?
No
Yes
PCB
no problem
Alternate with
explanation
(Refer to the
Note)
3While the product is
operating under EZ-ON start,
is the voltage of both ends
of the D32 over 8 V?
No
Yes
Replace the
Relay 2
4Replace the PCB.
EBR67471707
[Note]
If something is caught in the door or in the sealing area, the
microwave oven cannot operate safely. The latch switches
and monitor switch will prevent operation.

-20-
5Is there any beep sound
in continuity test between
the ends of latch board?
(Boor should be closed)
Power Off
Yes
No Adjust latch
board
(Refer to 9-1,
9-2)
7Is the resistance of high
voltage Transformer out of
rage?
Test Point
1. Primary winding: 0.2 ~ 0.5 Ohm
2. Secondary: 50 ~ 120 Ohm
3. Filament winding: 0 Ohm
No
Yes
Replace the
High Voltage
Transformer.
6Is the connector connected
to High Voltage Transformer
assembly disconnected or
disassembled?
No
Yes
Reconnect or
repair
the connector.