Maytag Mmv5207aaw, Mmv5207aaq, Mmv5207aab Service Manual

Microwave Oven
Service Manual

MMV5207AAB
MMV5207AAQ
MMV5207AAS
MMV5207AAW

CAUTION

BEFORE SERVICING THE UNIT, READ THE
SAFETY PRECAUTIONS IN THIS MANUAL.

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.

MODEL MMV5207AAB

MMV5207AAQ
MMV5207AAS
MMV5207AAW

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 (I)................................................................................................................................... 5-1

SCHEMATIC DIAGRAM (II).................................................................................................................................. 5-2

MATRIX CIRCUIT FOR TOUCH KEY BOARD .................................................................................................... 5-3

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.......................................................................................................................... 7-20

C.TROUBLESHOOTING .................................................................................................................................... 7-22

EXPLODED VIEW ................................................................................................................................................ 8-1

REPLACEMENT PARTS LIST ............................................................................................................................. 8-9

SPECIFICATIONS

Rated Power Consumption ................................1700W maximum

Microwave Output ...............................................1100W (IEC 60705)

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

............................................................................Oven Thermostat: Open at 110 °C ±5 °C

............................................................................Fuse(20A)

............................................................................Primary Interlock Switch

............................................................................Secondary Interlock Switch

............................................................................Interlock Monitor Switch

Magnetron ..........................................................2M282J (Toshiba)

Cook top Lamp ...................................................120 V, 20 W (Halogen)

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)x167/16”(H)x153/8”(D)

Oven Cavity Size ...............................................231/2”(W)x103/16”(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, Defrost Plate .

(Microwave oven+Cook top lamps+Ventilation fan)

Close at 60 °C ±5 °C

Close at 0 °C ±5 °C

SWITCH CHART

PRIMARY

SWITCH MODE

CONDITIONS

DOOR OPEN
DOOR CLOSED

NOTE: Use the above switch chart with circuit diagram on page 5-1.

INTERLOCK

SWITCH

COM

NO

OPEN OPEN CLOSE

CLOSE CLOSE OPEN

1-1

SECONDARY

INTERLOCK

SWITCH

COM

NO

INTERLOCK

MONITOR

SWITCH

COM

NC

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.

• 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.

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.

• 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.

ANTENNA

COOLING FIN

MAGNETRON
CHASSIS GROUND

Gasket

FILAMENT
TERMINALS

MAGNETRON

THE OVEN IS TO BE SERVICED ONLY
BY PROPERLY QUALIFIED SERVICE
PERSONNEL.

2-1

INSTALLATIONS

Plug with Ground
Prong

Properly Polarized
and Grounded
Outlet

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.

3-1

CONTROL PANEL

1

2

5

8

15

16

18

21

23

26

27

24

19

9

6

3

4

7

10

11

12

13

14

20

22

25

28

17

OPERATING INSTRUCTIONS

4-1

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. 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.

3. COOK: Touch this pad to cook Potato, Vegetable,

Casserole, Rice and Frozen Entree. The oven’s
sensor will tell the oven how long to cook depending
on the amount of humidity coming from the food.

4. REHEAT: Touch this pad to reheat Pizza, 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.

5. POULTRY: Touch this pad to cook chicken wings,

chicken nuggets, Spicy Chicken and Mexican
Chicken.

6. SOFTEN: Touch this pad to soften Butter, Ice Cream,

Cream Cheese and Frozen Juice.

7. MELT: Touch this pad to melt Butter, Chocolate,

Cheese and Marshmallows.

8. AUTO DEFROST: Meat, poultry, fish and bread.

Touch this pad to select food type and defrost food by
weight.

9. TIME DEFROST: Touch this pad to defrost most other

frozen foods.

at 100% power level.

14. CUSTOM PROGRAM: Touch this pad to recall one

cooking instruction previously programmed into
memory.

15. NUMBER: Touch number pads to enter cooking time,

power level, quantities, or weights.

16. MORE: Touch this pad to add ten seconds of cooking

time each time you press it.

17. LESS: Touch this pad to subtract ten seconds of

cooking time each time you press it.

18. POWER LEVEL: Touch this pad to select a cooking

power level.

19. CONTROL SETUP: Touch this pad to change the

oven’s default settings for sound, clock, display speed
and defrost weight.

20. COOK TIME: Touch this pad to to set a cooking time.

21. STOP/CLEAR: Touch this pad to stop the oven or to

clear all entries.

22. ENTER/START: Touch this pad to start a function. If

you open the door after oven begins to cook, touch
ENTER/START again.

23. KITCHEN TIMER: Touch this pad to set the kitchen

timer.

24. LIGHT TIMER: Touch this pad to set the light timer.

10. RAPID DEFROST: This pad provides RAPID defrost

for 1.0 pound of frozen food.

11. CLOCK: Touch this pad to enter the time of day.

12. HOLD WARM: Touch this pad to keep hot, cooked

foods warm in your microwave oven for up to 90
minutes.

13. ADD 30 SEC.: Touch this pad to set and start quickly

25. LIGHT HI/LO/OFF: Touch this pad to turn on the

cooktop/ countertop light.

26. VENT ON/OFF: Touch this pad to turn the fan on/off.

27. VENT 5-SPEED: Touch this pad to choose one of 5

fan speeds.

28. VENT AUTO TIME SET: Touch this pad when setting

ventilation time. (1, 3, 5, 10, 30 minutes.)

4-2

OVERALL CIRCUIT DIAGRAM

BN

H.V.DIODE

60Hz

120V

AC

WH

THERMOSTAT

M.G.T

THERMOSTAT

OVEN

SECONDARY
SWITCH

H.V.

FUSE 20A

BK

O.L

PRIMARY
SWITCH

RD

RD

RS.

RC.

F.M

T.T.M

BN

MONITOR

SWITCH

RD

TRANSFORMER

H.V.

WH

V.M

CAPACITOR

C.L

S.M

HIGH

C

CONDENSER

BL

THERMISTOR

ABSOLUTE
HUMIDITY
SENSOR

YL

BK

RD

RD

RD

GN

BK

RD

RD

BK

BL

BL

BK

BK

BK

BK

BN

YL

YL

BL

WH

WH

WH

WH

YL

YL

PK

BL

1

2

3

5

CN1

RY7

POWER
RELAY

3

123456

1’ 2’ 3’ 4’ 5’ 6’

21

3’2’1’

12
1’2’

8

6

7

9

TAP

3

TAP

2

1

TAP

4

12

11

10

YLBL WH WH RD BK

12 PIN CONNECTOR(CN1)

CONTROL MODULE

WIRE COLORS

3 PIN(CN3)

CONNECTOR

(FOR SENSOR)

BN BK PK BL

CN3

321

3 TAP
POWER
RELAY

SCR1
VENT
FAN
5 LVL

RY5
VENT
FAN
ON/OFF
RELAY

RY3
C/TOP
LAMP
LOW
RELAY

RY2
C/TOP
LAMP
HIGH
RELAY

RY1
MAIN
RELAY

L.V.
TRANS­FORMER

F

FA

MAGNETRON

()

()

SCHEMATIC DIAGRAM (I) *Check the Model No.

5-1

SCHEMATIC DIAGRAM (II) *Check the Model No. (ADD Noise filter)

5-2

MATRIX CIRCUIT FOR TOUCH KEY BOARD

13

12

8

9

10

11

2

1

3

4

5 6 7

KEY MATRIX

5-3

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 “0 ” three 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 7-3.

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 0W to

1100W 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.

6-1

SERVICE INFORMATION

PRECAUTIONS AND REPAIR SERVICE TIPS

PRELIMINARY

A. SINCE NEARLY 4000 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 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 by-passed.

7-1

MICROWAVE LEAKAGE TEST

CAUTIONS

• Be sure to check microwave leakage prior to
servicing the oven if the oven is operative prior to
servicing.

• The service personnel should inform the
manufacture importer, or assembler of any certified
oven unit found to have a microwave emission level
in excess of 5 mW/cm2and should repair any unit

found to have excessive emission levels at no cost to
the owner and should ascertain the cause of the
excessive leakage.The service personnel should
instruct the owner not to use the unit until the oven has
been brought into compliance.

• If the oven operates with the door open,the service
personnel should;

- Tell the user not to operate the oven

- Contact the manufacturer and CDRH (Center for
Devices and Radiological Health)immediately.
NOTE: Address on CDRH

Office of Compliance (HFZ-312)
Center for Devices and Radiological Health
1390 Piccard Drive Rockville,Maryland 20850

• The service personnel should check all surface and
vent openings for microwave emission testing.

• Check for microwave energy leakage after every
servicing.The power density of the microwave
radiation leakage emitted by the microwave oven
should not exceed 1mW/cm.sq.And always start
measuring of an unknown field to assure safety for
operating personnel from radiation leakage.
NOTE: The standard is 5mW/cm.sq.while in the
customer ’s home.1mW/cm.sq.stated here is
manufacturer ’s own voluntary standard for units in
customer ’s home.

EQUIPMENT-

• TESTER ((VOLTS-DC,AC,Ohmmeter)

• Microwave survey meter

- Holaday HI-1500
HI-1501

- Narda 8100

8200

• 600 cc non conductive material beaker ((glass or
plastic),inside diameter:approx.8.5 cm (3 1 /2 in.)

• Glass thermometer::100 °C or 212 °F (1 deg scale)

MEASURING MICROWAVE ENERGY
LEAKAGE

• Pour 275±15cc of 20±5°C(68±9°F) water in a beaker
which is graduated to 600 cc, and place the beaker
on the oven.

• Set the energy leakage monitor to 2,450 MHz and
use it following the manufacturer's recommended
test procedure to assure correct result.

• When measuring the leakage, always use the 2-inch
(5cm) spacer supplied with the probe.

• Operate the oven at its maximum output.

• Measure the microwave radiation using and
electromagnetic radiation monitor by holding the
probe perpendicular to the surface being measured.

Move probe along shaded area.

Probe scanning speed
Less than 2.5 cm/sec. ( 1 in/sec)

7-2

MEASUREMENT WITH THE OUTER CASE
REMOVED

(1) When you replace the magnetron,measure for

microwave energy leakage before the outer case
is installed and after all necessary components
are replaced or adjusted.Special care should be
taken in measuring the following parts.

-Around the magnetron

-The waveguide

WARNING: AVOID CONTACTING ANY HIGH

VOLTAGE PARTS.

NOTE WHEN MEASURING

(1) Do not exceed meter full scale deflection.
(2) The test probe must be removed no faster than

1 inch/sec (2.5cm/sec)along the shaded area,
otherwise a false reading may result.

(3) The test probe must be held with the grip portion

of the handle.A false reading may result if the
operator ’s hand is between the handle and the
probe.

(4) When testing near a corner of the door,keep

the probe perpendicular to the surface making
sure the probe horizontally along the oven
surface,this may possibly cause probe damage.

MEASUREMENT WITH A FULLY
ASSEMBLED OVEN

(1) After all components,including the outer

panels,are fully assembled,measure for
microwave energy leakage around the door
viewing window,the exhaust opening and air
inlet openings.

(2) Microwave energy leakage must not exceed the

values prescribed below.

NOTES:

Leakage with the outer panels removed -less
than 5 mW/cm2.
Leakage for a fully assembled oven (“Before the
latch switch (primary)is interrupted ”)with the door
in a slightly opened position -less than 1 mW/cm

2

POWER OUTPUT MEASUREMENT

(1) Microwave power output measurement is made

with the microwave oven supplied at its rated voltage and
operated at its maximum microwave power setting with a
load of (1000 ±5)g of potable water.

(2) The water is contained in a cylindrical borosilicate

glass vessel having a maximum material thickness
of 1/8 ” ((3 mm)and an outside diameter of approximately

7.6 ” ((190mm).

(3) The oven and the empty vessel are at ambient

Temperature(T0)prior to the start of the test.

(4) The initial temperature (T1)of the water is

(10 ±1)°C (50 °F)It is measured immediately before the
water is added to the vessel.After addition of the water to
the vessel,the load is immediately placed on the center
of the turntable which is in the lowest position and the
microwave power switched on.

(5) The time t for the temperature of the water to rise

by a value T of (10 ±1)°K is measured,where t is the
time in seconds and T is the temperature rise.
The initial and final water temperatures are selected so
that the maximum difference between the final water

temperature and the ambient temperature is 5 °K.
(6) The microwave power output P in watts is calculated
from the following formula :

RECORD KEEPING AND NOTIFICATION
AFTER MEASUREMENT

(1) After adjustment and repair of any microwave

energy interruption or microwave energy blocking
device,record the measured values for future
reference.Also enter the information on the
service invoice.

(2) Should the microwave energy leakage not be

more than 1 mW/cm 2 after determining that all
parts are in good condition,functioning properly
and genuine replacement parts which are listed in
this manual have been used.

(3) At least once a year,have the electromagnetic

energy leakage monitor checked for calibration
by its manufacturer.

4,187 Mw(T2 –T1)+0.55Mc(T2 –T0)

P =

is measured while the microwave generator is
operating at full power.Magnetron filament heat-up
time is not included.(about 3 sec)

(7) The water is stirred to equalize temperature

throughout the vessel,prior to measuring the final
water temperature.

(8) Stirring devices and measuring instruments are

selected in order to minimize addition or removal of
heat.

Where

P is the microwave power output,in watts:
Mw is the mass of the water,in grams:
Mc is the mass of the container,in grams:
T0 is the ambient temperature,in °C:
T1 is the initial temperature of the water,in °C:
T2 is the final temperature of the water,in °C:
t is the heating time in seconds,excluding the magnetron filament heat-up time.

WATER LOAD

7-3

t

GLASS TRAY

DISASSEMBLY INSTRUCTIONS

Power Transformer

Control Panel

Screw

Circuit Board

(CN3)

(RY7)

3 Tap
Power Relay

(CN1)

Circuit Board

Control Bracket

Circuit Board

FPC Connector(S1)

IMPORTANT NOTES:

UNIT MUST BE DISCONNECTED FROM ELEC­TRICAL OUTLET WHEN MAKING REPAIRS,RE­PLACEMENTS,ADJUSTMENTS AND CONTIN­UITY CHECKS.
WHEN RECONNECTING THE WIRE LEADS TO
ANY PART,MAKE SURE THE WIRING CONNE­CTIONS AND LEAD COLORS ARE CORRECTLY
MATCHED ACCORDING TO THE OVERALL CIR­CUIT DIAGRAM.(ESPECIALLY SWITCHES AND
HIGH VOLTAGE CIRCUIT.)

A. REMOVING POWER AND CONTROL
CIRCUIT BOARD (Figures 1, 2 and 3)

(1) Remove a screw securing the control panel

assembly to the oven cavity.
(2) Remove the control panel with pushing it upward.
(3) Remove the connectors (CN1, CN3) and wire

leads (3 Tap Power Relay, RY7) from the circuit

board.

(4) Remove 5 screws securing the circuit board.

Figure 2

(5) Remove the FPC connector from the terminal

socket following “HOW TO REMOVE THE FPC
CONNECTOR ” on the next page..

(6) Remove the circuit board from the control bracket

carefully.

Figure 1

7-4

Figure 3

HOW TO REMOVE THE F.P.C. CONNECTOR

F.P.C.
Connector

Terminal
socket

Plastic

fastener

Holes

Hook

Plastic fastener

Terminal

socket

F.P.C.

Connector

Plastic
fastener

Terminal

socket

F.P.C.

Connector

Terminal

socket

Plastic fastener

Holes

Hook

HOW TO INSERT THE F.P.C. CONNECTOR

Follow the steps below as illustrated in Figures 4
and 5 to remove the F.P.C.connector.

(1) Hold the edges of the plastic fastener with

thumb and forefinger.
(Figure 4)

(2) Lift up the lever of the plastic fastener from

the terminal socket by lightly pressing the
lever end with forefinger.
(Figure 5)

(3) Remove the F.P.C.connector from the

terminal socket.

Follow the steps below as illustrated in Figures 6
and 7 to insert the F.P.C.connector.
(1) Insert the F.P.C.connector into the terminal

socket securely with the fingers.

(2) Hold the plastic fastener with thumb and

forefinger of the other hand,and push it
slowly into the terminal socket.(Figure 6)
NOTE: When reconnecting the F.P.C

connector make sure that the holes
on the F.P.C.connector are properly
engaged with the hooks on the plastic
fastener

(3) Lock the level of the plastic fastener into the

hook of the terminal socket securely by
releasing the fingers.
(Figure 7)

Figure 4

Figure 6

Figure 5

Figure 7

7-5

B. REMOVING THE OUT CASE(Figure 8)

Door

Mount,All

Vent Grille

Controller

Out Case

Mounting
Plate

Power cord

(1) Remove the vent grille by removing two screws

securing it to the out case.
(2) Remove two screws securing it to the air duct.
(3) Remove the mounting plate by turning the screws

(1 or 2 screws)securing it to the out case.
(4) Remove two screws on the left central edge and

two screws on the right central edge of Base plate.

Remove the Mount,All from the out case by

removing one screw securing it to the out case.
(5) Remove four screws of the rear cavity.
(6) Remove the outcase with disconnecting power

cord connector.

Figure 8

7-6

C REMOVING THE DOOR INTERLOCK

Latch Board

Primary Interlock Switch

RD(from P.C.B)
RD(from Fan Motor)
BK(from Cooktop lamp)

WH(from H.V.T)

PK(from P.C.B)
BL(from P.C.B)

RD

(from Turntable Motor)

RD(from P.C.B)

BK

(from MGT THERMOSTAT)

Monitor Interlock Switch

Secondary Interlock Switch

Latch Board

Primary
Interlock Switch

Interlock
Monitor Switch

Secondary
Interlock Switch

SWITCHES (Figures 9,10)

(1) Disconnect the wire leads from the interlock

switches.
(2) Remove two screws securing the Latch Board.
(3) Make necessary replacements and check

microwave energy leakage according to

“ADJUSTMENT PROCEDURES ” on page 7-12.

Figure 9

Figure 10

WIRE COLOR

SYMBOL COLOR

WH WHITE

BK BLACK
BR BROWN
RD RED

YL YELLOW
PK PINK

BL BLUE
GY GREY
GN GREEN

N.P.

Not Provided

7-7

D. REMOVING MAGNETRON

Mount, AII

Vent Grille

Magnetron

(Figures 11 Through 12)

(1) Remove the vent grille by loosening two screws.

(Figure 11)
(2) Remove the outcase.See page 7-6.
(3) Remove four tap tite screws securing the

magnetron to the wave guide.
(4) Disconnect the leadwire.
(5) Remove the magnetron VERY CAREFULLY.

NOTES:

• When removing the magnetron,make sure that its

dome does not hit any adjacent parts,or it may be
damaged.

• When replacing the magnetron,be sure to install the

magnetron gasket in the correct position and be sure
that the gasket is in good condition.

• After replacing the magnetron,check for microwave

energy leakage with a survey meter Check
microwave energy leakage must be below the limit
of 5 mW/cm 2 .(All service adjustments should be
made for minimum microwave energy leakage
readings.)

E. REMOVING STIRRER FAN

(Figures 13 and 14)

(1) Remove one rivet ASS'Y securing it to the oven

upper plate by using knife blade.
(2) Pull out the stirrer fan cover.
(3) Remove two rivets ASS'Y securiting it to the oven

upper plate by using knife blade.
(4) Remove the stirrer fan.

Figure 13

Figure 11

Figure 14

Figure 12

7-8

F. REMOVING DOOR (Figure 15)

Door Screen

Mount, All

(1) Remove the vent grille by two screws securing it to

the outcase loosening.

(2) Lift up and draw the door.

NOTES:

• After replacing the door,be sure to check that the
primary interlock switch,the secondary interlock
switch and the interlock monitor switch is in good
operating normally.

• After replacing the door,check for microwave energy
leakage with a survey meter.Microwave energy
leakage must be below the limit of 5mW/cm 2 .(With a
275 ml water load)

H. ASSEMBLING DOOR

(1) When mounting the door assembly to the oven

assembly,be sure to adjust the door assembly
parallel to the chassis.Also adjust so the door has no
play between the inner door surface and oven frame
assembly.If the door assembly is not mounted
properly,microwaves may leak from the clearance
between the door and the oven..

I. REMOVING THE VENTILATION MOTOR

(1) Remove the mounting plate by loosening

mounting plate screws (1 or 2 screws)
securing it to the back plate.
(See Figure 17)

(2) Remove MOUNT ALL loosening one screw

loosening one screw securing the ventilation Motor
and back plate.(See Figure 18-a)

Figure 15

G. DISASSEMBLING DOOR (Figure 16)

(1) Remove the dielectric choke by using knifeblade

or small screw driver,etc.

(2) Remove two screws securing it to the door handle.

CAUTION: Be careful not to damage door seal

plate with the screwdriver.

Figure 17

Figure 16

Figure 18-a

7-9

(3) Carefully pull the ventilation motor ASS'Y out ofthe

Wire Leads

Turntable Motor

microwave oven.(See Figure 18-b)

Figure 18-b

J. REMOVING THE TURNTABLE MOTOR

(1) Remove the glass tray and rotating ring.
(2) Remove the turntable shaft VERY CAREFULLY

with a hand.(Figure 19)

(3) Remove the base plate by removing 8 screws

securing it to the oven cavity.(Figure 20)

(4) Disconnect the leadwire from the turntable motor

terminals.

(5) Remove the 1 screws securing the turntable motor

to the oven cavity ASS'Y.(Figure 21)

NOTES:

• Remove the leadwire from the turntable motor
VERY CAREFULLY.

• Be sure to grasp the connector not the wires when
removing.

Figure 19

Figure 20

7-10

Figure 21

K. REPLACING THE HUMIDITY SENSOR

(1) Remove the sensor by removing two screws

securing it to the air duct. (See Figure 22)

(2) Mount the new humidity sensor to the air duct.

Figure 22

7-11

INTERLOCK SYSTEM

Interlock
Monitor Switch

LATCH

LATCH BOARD

0-1/64"

0-1/64"

Latch Board

Primary
Interlock Switch

Secondary
Interlock Switch

INTERLOCK MECHANISM

The door lock mechanism is a device which has been specially designed to eliminate completely microwave
activity when the door is opened during cooking and thus to prevent the danger resulting from the microwave
leakage.

ADJUSTMENT PROCEDURES

To avoid possible exposure to microwave energy
leakage,adjust the door latches and interlock
switches,using the following procedure.

The Interlock Monitor and Primary Interlock Switch act
as the final safety switch protecting the user from
microwave energy.The terminals between “COM ” and
“NC ” of the Interlock Monitor must close when the door
is opened.After adjusting the Interlock Monitor Switch,
make sure that it is correctly connected.
Mounting of the primary/monitor/secondary switches to
the latch board.

CHECK THE DOOR LATCH AND SWITCH
CLOSING.

NOTE:

The outer cover of the microwave oven is
removed.

(1) Set the microwave oven on its side so that you can

see the latch board and the switches,as shown in
Figure 23-a.

(2) Close the door tightly and check gaps A and B to

be sure they are no more than 1/64 ” (0.5 mm).
See Figure 23-b for close-up view of gaps A and B
(door latches).If all gaps are less than 1/64 ”
(0.5 mm),adjustment of the latch board may not
be necessary.Go to Steps 5 and 6 to check the
sequence of the switches.

NOTE:

To correct sequence of the Primary Interlock
Switch,Secondary Interlock Switch and the
Interlock Monitor Switch is very important.

If any gap is larger than 1/64” (0.5 mm), you will
need to adjust the latch board”. Go to step 3
and follow all steps in order.

Figure 23-a

Figure 23-b

ADJUST THE LATCH AND SWITCH CLOSING

(3) Loosen the two screws holding the plastic latch

board as shown.

(4) With the oven door closed tightly,move the latch

board upward toward the top of the oven and/or
away from the door latch until the gaps are less
than 1/64 ” (0.5 mm).
Hold the latch board tightly in this position until you
check the sequence of the switches in steps 5
and 6.

7-12

TEST THE LATCH AND SWITCH SEQUENCE

(5) Open the oven door slowly.Watch the door latch,

the Secondary Switch.Release Rod and Lever
on the switches to make sure they are zero to the
body of the switches in the following sequence:

-Primary Interlock Switch

-Secondary Interlock Switch

-Interlock Monitor Switch

Adjust the latch board until the switches operate in

this sequence.See Steps 3 and 4.

(6) Close the oven door slowly and be sure it is tightly

closed.Watch the three switches to make sure
they are zero to the body of the switches in the
following sequence:

-Interlock Monitor Switch

-Primary Interlock Switch

-Secondary Interlock Switch

NOTE: The Interlock Monitor Switch is an added

safety check on the Primary and
Secondary Interlock Switches.If the
Primary and Secondary Interlock Switches
allow the oven to operate with the door
open,the Monitor Switch will blow the
fuse.

(7) When you achieve the proper sequence of

switches in Steps 5 and 6,tighten the latch board
screws at that point.

TEST THE MICROWAVE ENERGY LEAKAGE

Make sure the microwave energy leakage is below the
limit of 1mW/cm 2 (with a 275 ml water load)and
5mW/cm 2 (with a 275 ml water load without the
cabinet)when measured with a survey meter.

7-13

INTERLOCK CONTINUITY TEST

A. PRIMARY INTERLOCK SWITCH TEST

When the door is opened slowly,an audible click
should be heard at the same time or successively
at intervals and the latches should activate the
switches with an audible click
If the latches do not activate the switches when the
door is closed,the switches should be a adjusted
in accordance with the adjustment procedure.
Disconnect the wire lead from the primary switch.
Connect the ohmmeter leads to the common
(COM)and normally open (NO)terminal of the
switch.The meter should indicate an open circuit
in the door open condition.
When the door is closed,the meter should indicate
a closed circuit.
When the primary switch operation is abnormal,
make the necessary adjustment or replace the
switch only with the same type of switch.

B.S ECONDARY INTERLOCK SWITCH TEST

Disconnect the wire lead from the secondary
switch.
Connect the ohmmeter leads to the common
(COM)and normally open (NO)terminals of the
switch.The meter should indicate a open circuit in
the door open condition.When the door is closed,
meter should indicate an closed circuit.When the
secondary switch operation is abnormal,make the
necessary adjustment or replace the switch only
with the same type of switch.

C. MONITOR SWITCH TEST

Disconnect the wire lead from the monitor switch.
Connect the ohmmeter leads to the common
(COM)and normally closed (NC)terminals of the
switch.The meter should indicate closed circuit in
the door open condition.When the door is closed,
meter should indicate an open circuit.When the
monitor switch operation is abnormal,replace with
the same type of switch.

NOTE: After repairing the door or the interlock
system, it is necessary to do this continuity
test before operating the oven.

COMPONENTS TEST PROCEDURE RESULTS

SWITCHES Check for continuity of the Door Door
(Wire leads removed) switch with an Ohm-meter open closed

Primary

Switch

Monitor

Switch

Secondary

Switch

COM

COM

COM

NO

NC

NO

NOTE : After checking for the continuity of switches,make sure that they are

connected correctly.

WARNING : FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION

EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS.

TYPE NO.SZM-V16-FA-63 OR VP-533A-OF OR V-5230Q FOR PRIMARY SWITCH
TYPE NO.SZM-V16-FA-62 OR VP-532A-OF OR V-5220Q FOR MONITOR SWITCH
TYPE NO.SZM-V16-FA-63 OR VP-533A-OF OR V-5230Q FOR SECONDARY SWITCH

7-14

TEST AND CHECKOUT PRECEDURES AND TROUBLESHOOTING

CAUTIONS

1. DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE OUTER CASE
FROM THE UNIT.PROCEED WITH THE TEST ONLY AFTER DISCHARGING THE HIGH VOLTAGE CAPACITOR
AND REMOVING THE LEAD WIRES FROM THE PRIMARY WINDING OF THE HIGH VOLTAGE TRANSFORMER.

2. ALL OPERATIONAL CHECKS WITH MICROWAVE ENERGY MUST BE DONE WITH A LOAD (1 LITER OF
WATER IN CONTAINER)IN THE OVEN.

A. TEST PROCEDURES

COMPONENTS TEST RESULTS

TRANSFORMER

MAGNETRON

FILAMENT
WINDING

PRIMARY
WINDING

SECONDARY
WINDING

1. Remove wire leads.

2. Measure resistance. (ohm meter scale: Rx1)

• Primary winding High
Low

• Secondary winding

• Filament winding

3. Measure resistance. (ohm meter scale: Rx1000)

• Primary winding to ground

• Filament winding to ground

Antenna

Gasket

Approx. 0.2 to 0.5 ohms
Approx. 0.2 to 0.5 ohms
Approx. 50 to 120 ohms
0 ohm

Normal: Infinite
Normal: Infinite

Chassis

Filament

1. Remove wire leads. Install the magnetron seal in
the correct position. Check that the seal is in
good condition.

2. Measure resistance. (ohm meter scale: Rx1)

• Filament terminal

3. Measure resistance. (ohm meter scale: Rx1000)

• Filament to chassis

7-15

Normal: Less than 1 ohm

Normal: Infinite

COMPONENTS TEST RESULTS

A

B

C

CAPACITOR

DIODE

Some inexpensive ohm
meters may indicate infinite
resistance in both directions.

1. Remove wire leads.

2. Measure resistance. (ohm meter scale: Rx1000)

• Terminal to terminal

• Terminal to case

1. Measure continuity. Forward.
(ohm meter scale: Rx1000)

2. Measure continuity. Reverse.
(ohm meter scale: Rx1000)

Normal:
Momently indicates
several ohm, and then
gradually returns to infinite
Normal: Infinite.

Normal:Continuity.
Abnormal: Infinite.

Normal: Infinite.
Abnormal: Continuity.

RELAY 7

FAN MOTOR

1. Measure continuity.
(ohm meter scale: Rx1)

2. Remove the lead wires and operate oven at

power level 1 through power level 10.

1. Remove wire leads.

2. Measure resistance.
(ohm meter scale: Rx1)

Power

Level

10

Open

1

4 Sec

2

6 Sec

3

8 Sec

4

10 Sec

5

12 Sec

6

14 Sec

7

16 Sec

8

18 Sec

9

20 Sec
22 Sec

Close

18 Sec
16 Sec
14 Sec
12 Sec
10 Sec

8 Sec
6 Sec
4 Sec
2 Sec
0 Sec

Normal: Approximately
Terminal : 35 to 50 ohms
Terminal : 5 to 15 ohms

A C

A B

Abnormal:
Infinite or several.

7-16

COMPONENTS TEST RESULTS

RD

BK

WH

1
2
3

VENTILATION MOTOR

TURNTABLE MOTOR

ABSOLUTE HUMIDITY
SENSOR

1.Remove lead wires.

2.Measure resistance.
(ohm meter scale:Rx1)

1. Remove wire leads.

2. Measure resistance.
(ohm meter scale: Rx1000)

1. Disconnect sensor connector from micom
computer board.

2. Measure resistance terminal to terminal (ohm
meter scale: R X 1000)

Normal:
Approximately 20 to 40 ohms
Abnormal:Infinite

Normal: Approximately

2.5 to 3.5 Kohms
Abnormal:
Infinite or several.

Normal:
Approximately
BK-RD: 6.0 Kohms
RD-WH: 3.0 Kohms
BK-WH: 3.0 Kohms
Abnormal:
Infinite or approx. 0 ohm

STIRRER MOTOR

1.Remove lead wires.

2.Measure resistance.

(ohm meter scale:Rx1000)

Normal:
Approximately 120 to 135 ohms
Abnormal:Infinite

7-17

COMPONENTS TEST RESULTS

1
2
3
4
5
6
7
8
9
10
11
12
13

13

12

8

9

10

11

2

1

3

4

5 6 7

TOUCH KEY BOARD

Measure the resistance between terminal
pins of connector KEY CONNECTOR.

NOTE:

When reconnecting the FPC connector,
make sure that the holes on the FPC
connector are properly engaged with hooks
on the plastic fastener.

MATRIX CIRCUIT FOR

TOUCH KEY BOARD

CONNECTOR(KEY CON)

When

Resistance

value

touched

Less than
400 ohms

FPC CONNECTOR

Top

When not
touched

More than
1 mega ohm

NOTES:

• A MICROWAVE ENERGY TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS SERVICED FOR
ANY REASON.

• MAKE SURE THE WIRE LEADS ARE IN THE CORRECT POSITION.

• WHEN REMOVING THE WIRE LEADS FROM THE PARTS,BE SURE TO GRASP THE CONNECTOR,NOT
THE WIRES.

7-18

B. CHECKOUT PROCEDURES

(1) CHECKOUT PROCEDURES FOR FUSE BLOWING

CAUTION: REPLACE BLOWN FUSE WITH 20 AMPERE FUSE.

PROBLEMS CAUSES

Fuse blows immediately after
the door is closed.

Improper operation of the primary interlock,secondary

Fuse blows immediately after
the door is opened.

interlock switches and/or the interlock monitor switch.

Fuse blows when the door is closed and START
key is touched.

NOTES:

• If the fuse is blown by an improper switch operation,replace all switches and the fuse at the same time.
After replacing the defective switches with new ones,make sure that they are correctly connected.

• Check for microwave energy leakage according to INTERLOCK ADJUSTMENT PROCEDURES on page
7-12 when the primary interlock,secondary interlock switches and/or the interlock monitor switches are
adjusted or replaced.

Malfunction of the high voltage transformer;the high
voltage capacitor including the diode,the magnetron,
the blower motor or the circuit board.

7-19

(2)CHECKOUT PROCEDURES FOR RELAY.

-PROBLEM (A)-

FAN motor turns on without touching START key

when the door is closed.

NO

GOOD

Remove the mate connector of I/O
CON from the circuit board.
Does the unit still operate?

NO

Replace the
circuit board

YES

YES

Defective

Wire Assembly

Replace

Wire Assembly

-PROBLEM (A)--

Oven lamp turns on without touching START key

when the door is closed.

GOOD

NO

Remove the mate connector of I/O
CON from the circuit board.
Does the unit still operate?

NO

Replace the
circuit board

YES

YES

Defective

Wire Assembly

Replace

Wire Assembly

-PROBLEM (B)-

FAN motor turns on When the door is closed and

START key is touched.

YES

GOOD

Measure the voltage at pin NO.
1,4 of CN1
Voltage reading:120 V AC

NO

Replace the
circuit board

NO

YES

Defective
FAN motor

Replace

FAN motor.

-PROBLEM (B)-

Oven lamp turns on When the door is closed and

START key is touched.

GOOD

YES

Measure the voltage at pin NO.
1,4 of CN1
Voltage reading:120 V AC

NO

Replace the
circuit board

NO

YES

Defective
Oven lamp

Replace

Oven lamp

7-20

(3) CHECKOUT PROCEDURES FOR CIRCUIT

BOARD
The following symptoms indicate a defective circuit
board.

1) Check the input current.If the input current is more
than 20A,check the magnetron and wiring.If the
input current is less than 0.5 A,there is no input to
the H.V.T.

2) The start function fails to operate but the high
voltage Systems,the interlock switches,the door
sensing and the relay check good.

3) The unit with a normal relay continuously operates.

4) The buzzer does not sound or continues to sound.

NOTE: A MICROWAVE ENERGY LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS

SERVICED FOR ANY REASON.

5) Some segments of one or more digits do not light
up,or they continue to light up,or segments light
when they should not.

6) Wrong figures appear.

7) The figures of all digits.

8) The clock does not keep time properly.

7-21

Measure voltage between pin 1

and pin 3 of connector CN1.

BL

WH

Runs

Runs

0

120

0

120

120V

Replace

circuit board

Normal

circuit board

Normal

resistance

Voltage

incorrect

Correct

connections

Runs

Runs

Runs

Measure resistance of touch

key board after removing

connector S1.

(See page 7-5 and 7-18)

Normal

resistance

Resistance

incorrect

Replace touch

key board.

Normal touch

key board

Poor

contact

Correct

seating

Contact

ok

Replace

circuit board

Normal

circuit board

Normal

contact

Check contact

of connector S1

C. TROUBLE SHOOTING

• DISPLAY Problems, A thru C

• HELP UP Problems, D thru E • BUZZER Problems, F

Before following this troubleshooting read TRIAL OPERATION on page 6- 1.

PROBLEM - A: “PLEASE SET TIME OF DAY” does not appear in display window when power supply cord is

plugged into wall outlet.

2. FUSE (See “CHECKOUT PROCEDURES FOR FUSE BLOWING: on page 7- 19)

3. OVEN CAVITY THERMOSTAT

Check: 1. POWER SUPPLY

1

correct indications when programmed.

PROBLEM - B: Display does not show correct numbers and/ or

1

7-22

Check continuity of connector

CN1 between Pin 11(PK) and

pin 12(BL) when the door is

closed

Continuity

OK

Check contact of

connector S1

Contact

OK

Replace

Circuit board

Correct

Correct

seating

Normal

circuit board

Normal

contact

Poor

Normal Secondary

switch

No

continuity

Adjust or replace door

sensing switch.

Runs

Runs

Runs

Check operation of fan

motor when START key

is touched.

Measure resistance

of H.V.capacitor

(see page 7-16)

Resistance

incorrect

Measure resistance

of fan motor

Terminal A~C: 35 to 50 ohms

Terminal A~B: 5 to 15 ohms

Resistance

incorrect

Replace

fan motor

Normal

circuit board

Replace

Normal

fan motor

circuit board

Normal

resistance

Replace H.V.C.

Normal H.V.C.

Normal

magnetron

Replace

Normal

operation

No

operation

Runs

Runs

Runs

Runs

33

Normal

resistance

33

Check: 1. TOUCH KEY BOARD (START KEY FUNCTION)

PROBLEM - E: Display does not start countdown when START key is touched.

1

no heating is produced in oven load.

PROBLEM - D: Unit operation seems to be normal but

Check: 1. AIR VENTS

1

7-23

Runs

Runs

Runs

Contact

OK

NO

continuity

Replace

circuit board

Normal

circuit board

Poor contact

Replace

circuit board

Normal

circuit board

Contact OK

Normal

contact

Correct

seating

Check contact of

connector

Check the contact of

relay 7 (see page 7-16)

Resistance

incorrect

Check the continuity of

H.V.C. (see page 7-16)

Normal H.V.T.

Resistance

incorrect

Normal H.V.C.

Abnormal

Replace H.V.D.

Normal

Magnetron

Replace

Magnetron

Normal

Normal

H.V.D.

Check the

continuity of H.V.D.

(see page 7-16)

Replace H.V.C.

Normal

resistance

Replace H.V.T.

Normal

resistance

Runs

Runs

Runs

Runs

Measure resistance of

H.V.Transformer

(see page 7-15)

START key is touched for HIGH POWER cooking.

2. THERMOSTAT

Check: 1. PRIMARY AND SECONDARY INTERLOCK SWITCHES

PROBLEM - E: Unit does not heat up even if display counts down when

1

2

7-24

Normal

circuit board

Check normal

operation

circuit board

Replace

circuit board

Runs

Runs

Runs

Runs

Contact

OK

NO

contact

Replace

magnetron thermostat

and oven thermostat

Poor contact

Replace

circuit board

Normal

circuit board

Contact OK

Normal

contact

Correct

seating

Check contact

of connector

(see page 7-5)

Runs

Replace

ventilation

motor ASS Y

NO runs

Normal

ventilation

motor ASS Y

Check the contact of

magnetron thermostat

and oven thermostat

stages or at end of cooking

PROBLEM - F: No buzzing when touching the key, between

1

2. FUSE

Check: 1. POWER SUPPLY

PROBLEM - G: Ventilation fan does not operate when VENT ON/OFF key is touched.

1

7-25

1002

1005

1005

1000

1004

1006

W150

W109

1007

1012

1008

1003

1381

1000

1008

1004

1009

W105

1019

1007

1006

1002

W150

W109

1011

1011

1012

1009

1019

W105

#EV#

EXPLODED VIEW

DOOR PARTS

FOR MODEL: MMV5207AAB

MMV5207AAQ
MMV5207AAW

Serial Number ldentification

(Figure Check First & Second)
ex) 1 0

FOR MODEL: MMV5207AAS

8-1

*07

2004

2004

2000

2002

2006

2009

2381

2381

2008

W130

W130

2006

2009

2008

* Check the
Serial No.

*07

* Check the
Serial No.

#EV#

CONTROLLER PARTS

FOR MODEL: MMV5207AAB

MMV5207AAQ
MMV5207AAW

FOR MODEL: MMV5207AAS

8-2

W121

W107

3031

3001

3029

3005

W178

W202

3010

W138

W138

W142

For Model
MMV5207AAB
MMV5207AAS

For Model
MMV5207AAW
MMV5207AAQ

W142

3026

3011

3025

W121

W105

3045

3037

6000

3036

For Model
MMV5207AAB
MMV5207AAS

For Model
MMV5207AAW
MMV5207AAQ

3032

3009

3024

3018

3043

W108

#EV#

OVEN CAVITY PARTS

8-3

W102

4004

4003

4002

4002

4001

4000

#EV#

LATCH BOARD PARTS

8-4

#EV#

INTERIOR PARTS (I)

W110

3017

5024

3002

3008

5008

W101

5007

W109

5009

3007

5012

SPECIAL PARTS

5383

5003

5049

W109

W101

3054

3004

3009

W105

5044

W109

5002

W101

5000

5023

8-5

5018

W101

5051

W109

3027

W144

W109

W150

5027

5011

5029

5017

5412

5014

5010

5001

5006

5037

5038

5015

5045

5016

* Check the
Serial No.

* Check the
Serial No.

#EV#

INTERIOR PARTS (II - I)

10

Serial No.

Check the rating label of Model
and order SVC parts according to
the Serial No.

8-6

3027

W144

W109

W150

5027

5011

5029

5041

5412

5014

5010

5001

5006

5037

5038

5015

5045

5016

* Check the
Serial No.

* Check the
Serial No.

#EV#

INTERIOR PARTS (II - II)

11

Serial No.

Check the rating label of Model
and order SVC parts according to
the Serial No.

8-7

VINYL

BAG

6011

6009

6010

6008

#EV#

INSTALLATION PARTS

8-8

P/NO : 3828W5S3620 Printed in Korea