Sears 721.60483000 Basic Field Manual

DIVISION 20

BASIC FIELD MANUAL

FOR

MICROWAVE OVEN

MODEL 721.60483000

MODEL 721.60483000

October, 2000

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 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 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.

MODEL 721.60483000

-1-

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 721.60483000

MECHANICAL SERVICE INFORMATION

TABLE OF CONTENTS

1. Adjustment Procedures....................................................................................................................................... 3

2. Precautions on Installation .................................................................................................................................. 5

3. General Precautions in Use................................................................................................................................. 5

4. Trial Operation..................................................................................................................................................... 5

5. Specifications ...................................................................................................................................................... 6

6. Overall Circuit Diagram ....................................................................................................................................... 7-8

7. Operating Procedures ......................................................................................................................................... 9-11

8. Procedure for Measuring Microwave Energy Leakage........................................................................................ 12-13

9. Disassembly Instructions..................................................................................................................................... 14-18

10. Interlock Continuity Test.................................................................................................................................... 19

11. Test and Checkout Procedures, and Troubleshooting

A. Test Procedures............................................................................................................................................. 20-22

B. Checkout Procedures..................................................................................................................................... 23-25

C. Troubleshooting............................................................................................................................................. 26-30

MODEL 721.60483000

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-3-

MODEL 721.60483000

1. ADJUSTMENT PROCEDURES

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

ONLY AUTHORIZED SERVICE PERSONNEL
SHOULD MAKE THIS ADJUSTMENT.

The Interlock Monitor and Primary Interlock Switch acts
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. See Figures 1-a
and 1-b throughout this procedure.

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 1-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

1-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-U, L. Go to step 3 and follow all
steps in order.

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.

TEST THE LATCH AND SWITCH SEQUENCE

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

Primary 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

(8) Using a survey meter, make sure the microwave energy

is below 5 mW/cm.sq.

-4-

MODEL 721.60483000

LATCH BOARD

MONITOR
INTERLOCK
SWITCH

PRIMARY
INTERLOCK
SWITCH

SECONDARY
INTERLOCK
SWITCH

LATCH

LATCH BOARD

0-1/64"

0-1/64"

A

DOOR LATCH

DOOR LATCH

Figure 1-a

Figure 1-b

2. PRECAUTIONS ON INSTALLATION

(Figure 2)

A. Plug the power supply cord into a 120 V AC, 60 Hz,

single-phase power source with a capacity of at least 20
amperes.

B. Since the unit weights about 38 lbs, be sure to place it

on a sturdy and flat surface.

C. Avoid placing the unit in a location where there is direct

heat or splashing water.

D. Place the unit as far away as possible from TV, radio,

etc. to prevent interference.

CAUTION

3. 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 turntable tray 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.

4. 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. Touch the STOP/CLEAR and the COOK TIME keys.
C. Set cooking time for 10 minutes by touching “1”

and then “0” three times. “1000” appears in the

display window.
D. 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.
E. After about 5 minutes, make sure the primary interlock

switch, the secondary interlock switch and the interlock

monitor and oven lamp switch operate properly by

opening and closing the door several times. Touch the

START key each time the door is closed.
F. Continue operating the unit. Four long beep sound

signal is heard when the time is up. The unit will shut off

automatically.
G. Confirm the water is hot.
H. Finally, measure the output power according to

“POWER OUTPUT MEASUREMENT” on page 13.

5. FEATURES AND SPECIFICATIONS

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) Magnetron thermostat

(6) 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 100W to

1000W 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 can be set. The oven

remembers three cooking stages and changes from one

cooking stage to another. This is made possible with the

memory function of the microprocessor.

MODEL 721.60483000

-5-

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.

Three-Pronged(Grounding)
Plug

Figure 2

Properly Polarized and
Grounded
Outlet

SPECIFICATIONS

Rated Power Consumption..........................................1500W maximum

Output

..........................................................................1100W maximum (*IEC 705 Rating standard)

...................................................................Adjustable 100W through 1100W, 11 steps

Frequency....................................................................2,450 MHz ± 50 MHz

Power Supply...............................................................120V ±12V AC, 60Hz

Rated Current...............................................................13.0 Amp.

Magnetron Cooling.......................................................Forced Air Cooling

Microwave Stirring........................................................Turntable

Rectification..................................................................Rectification Voltage Doubler Half-Wave

Door Sealing ................................................................Choke System

Safety Devices.............................................................Thermostat:

Open at 90°C ± 5°C

Open at 75°C ± 5°C
Fuse(20A)
Primary Interlock Switch
Secondary Interlock Switch
Interlock Monitor

Magnetron....................................................................2M246

High Voltage Capacitor................................................Capacitor: 1.00µF, 2.1KV Ac

High Voltage Diode......................................................350mA, 9.0KV

Cavity Lamp.................................................................125V, 20W

Timer............................................................................Digital, up to 99 mm. 99 sec. (in each cooking stage)

Tray..............................................................................Tempered Safety Glass

Overall Dimensions......................................................23

7

/8”(W) x 139/16”(H) x 1913/16”(D)

Oven Cavity Size..........................................................17

17

/32”(W) x 107/8”(H) x 1821/32”(D)

Effective Capacity of Oven Cavity................................2.1 Cu.ft.

Accessories..................................................................Use and Care Manual ,Turntable,

Rotating Ring Assembly.

SWITCH CHART

NOTE: Use the above switch chart with circuit diagram on page 7.

MODEL 721.60483000

-6-

PRIMARY SECONDARY INTERLOCK
INTERLOCK INTERLOCK MONITOR
SWITCH SWITCH SWITCH

COM COM COM

NO NO NC

SWITCH MODE

CONDITIONS

DOOR OPEN

DOOR CLOSED

∞∞∞0

0

0

6. OVERALL CIRCUIT DIAGRAM
A. SCHEMATIC DIAGRAM

MODEL 721.60483000

-7-

IMPORTANT SAFETY NOTE: THE SHADED AREAS ON THIS SCHEMATIC DIAGRAM INCORPORATE SPECIAL FEATURES

IMPORTANT FOR PROTECTION FROM MICROWAVE RADIATION, FIRE, ELECTRICAL SHOCK, AND

HAZARDS. WHEN SERVICING IT IS ESSENTIAL THAT ONLY MANUFACTURER’S SPECIFIED PARTS

BE USED FOR THE CRITICAL COMPONENTS IN THE SHADED AREAS OF THE SCHEMATIC DIAGRAM.

NOTICE: SINCE THIS IS BASIC SCHEMATIC DIAGRAM, THE VALUES OF COMPONENTS AND

SOME PARTIAL CONNECTIONS ARE SUBJECT TO CHANGE FOR IMPROVEMENT.

NL

1
2
3
4

5
6
7
8

OL

FM

TTM

WH

SYMBOL

NOTE:

1. DOOR IS OPEN.

2.RS: SENSING
ELEMENT
RC: COMPENSATING
ELEMENT

3. WIRE COLOR.

COLOR
WHITE
BLACK

YELLOW
PINK

BLUE

GREEN
BROWN

BK

YL
PK

RED

RD

BL

GN
BN

H.V.DIODE

H.V. CAPACITOR

RDWH

BN(NC)(C)

YL

CN4

TURNTABLE

MOTOR

WH

GN

SECONDARY

INTERLOCK

SWITCH

WH

WH

WH

BK

BL

GN

PK

WH RD

RC RS

HUMIDITY

SENSOR

BK

RELAY 1

RELAY 2

L.V. TRANSFORMER

(CN1)

BK

RD

BK

FUSE

20A

PRIMARY
INTERLOCK
SWITCH
(NO)

BK

MONITOR SWITCH

H.V.TRANSFORMER

FAN

MOTOR

OVEN
LAMP

MGT/OVEN

THERMOSTAT

AC 120V/60Hz
SINGLE PHASE ONLY

MAGNETRON

321

B. MATRIX CIRCUIT FOR TOUCH KEY BOARD

MODEL 721.60483000

-8-

Figure 4

(Sensor)
Popcorn

(Sensor)

Cook

Express

Defrost

N.C

User

Choice

Timer

Time of

Day

Add

30 Sec

Quick

Defrost

(Sensor)

Reheat

Quick Touch

Cook

Quick

ON

MoreN.C Less

Power

Stop/
Clear

Time Start 8 9 0

1

N.C N.C N.C N.C N.C N.C

234567

7. OPERATING PROCEDURES
A. OVEN CONTROL PANEL

MODEL 721.60483000

-9-

Starts the oven.

Start

Display Window- Shows:

* Time of day.
* Cooking time.
* Cooking power level.
It also function as a
countdown timer
when cooking.

NOTE: A "beep" sounds when you touch a "key" on the control panel,
to indicate that you have entered a setting.

Add 30 Sec

Used to set cooking time
quickly and directly

Sensor Popcorn
Sensor Reheat

User Choice

Used to change the oven’s
default settings

Time of Day

Used in setting time of day

Sensor Cook

Quick Touch Cook

Used to select

programming food items

Quick On

Used to cook at 100%

power for 1 to 9 minutes

Numbers-

Used to enter the:
* Time of day.
* Cooking time.
* Cooking power.
* Food weight for defrost.

Time

Express Defrost

More/Less

Quick Defrost

Used to quick defrosting

for 1.0 pound

Stop/Clear

Stops the oven and

clears all entries except

CLOCK.

Once cooking has

begun, however,

CLEAR will function

only after STOP

has been touched.

Timer

You can use your

microwave oven

as a timer.

Power

Used select
cooking power level.

Figure 5

B. PANEL INSTRUCTIONS

The entire operation is done by simple touch control pads.

1. DISPLAY. The Display includes a clock and indicators that
tell you time of day, cooking time settings, and cooking
functions selected.

2. SENSOR COOK. This pad allows you to cook most of your
favorite foods without having to select cooking times and
power levels.

3. SENSOR REHEAT. This pad allows you to reheat
precooked room-temperature or refrigerated foods without
selecting cooking times and power levels.

4. QUICK TOUCH COOK. Touch this pad to select
programming food items.

5. QUICK ON. Touch this pad to cook at 100% cook power for
1 to 9 minutes.

6. TIMER. Touch this pad to use your microwave oven as a
kitchen timer.

7. USER CHOICE. Touch this pad to change the oven's default
settings for sound, clock, scroll speed, Lbs/Kg and demo
choice.

8. MORE/LESS. Touch this pad to adjust cook food for a
longer or shorter time.

9. QUICK DEFROST. This pad provides you with the quick
defrosting method for 1.0 pounds frozen foods.

10. EXPRESS DEFROST. This pad is an accurate defrosting
method for frozen meat, poultry and fish up to 6.0 lbs or 4.0
kgs.

11. TIME. Touch this pad to set a cooking time.

12. STOP/CLEAR. Touch this pad to stop the oven or clear

entries.

13. SENSOR POPCORN. This pad lets you pop commercially
packaged microwave popcorn.

14. ADD 30 SEC. Touch this pad to cook at 100% cook power
for 30 seconds to 99 minutes, 59seconds.

15. TIME OF DAY. Touch this pad to enter the time of day.

16. NUMBER PADS. Touch Number Pads to enter cooking

time, power level, quantities, or weights.

17. POWER. Touch this pad to set a cooking power.

18. START. Touch this pad to start all entries (except the

QUICK TOUCH and QUICK ON functions which start
automatically) and to turn Child Lock on or off.

MODEL 721.60483000

-10-

C. EASY USE CHART

(1) TIME OF DAY

1. Touch STOP/CLEAR.

2. Touch TIME OF DAY.

3. Touch numbers for correct time of day.

4. Touch START.

(2) TIMER

1. Touch STOP/CLEAR.

2. Touch TIMER.

3. Touch correct numbers for time.

4. Touch START.

(3) CHILD LOCK

To set:

1. Touch STOP/CLEAR.

2. Touch “START” more than 4 seconds.
To cancel:

1. Touch STOP/CLEAR.

2. Touch “START” more than 4 seconds.

(4) SENSOR COOK

1. Touch STOP/CLEAR.

2. Touch COOK.

3. Touch number for SENSOR COOK category.

(5) SENSOR REHEAT

1. Touch STOP/CLEAR.

2. Touch REHEAT.

3. Touch number from 1 to 3
(Touch 1: DINNER PLATE, Touch 2: SOUP/SAUCE,

Touch 3: CASSEROLE)

(6) SENSOR POPCORN

1. Touch STOP/CLEAR.

2. Touch POPCORN.

(7) QUICK TOUCH COOK

1. Touch QUICK TOUCH COOK.

2. Touch number for QUICK TOUCH COOK category.

3. Touch correct number for amount.

(8) ADD 30 SEC

1. Touch STOP/CLEAR.

2. Touch ADD 30 SEC.

(9) USER CHOICE

1. Touch STOP/CLEAR.

2. Touch USER CHOICE.

3. Touch number from 1 to 5
Touch 1: SOUND ON/OFF
Touch 2: CLOCK ON/OFF
Touch 3: SCROLL SPEED
Touch 4: LBS/KG
Touch 5: DEMO ON/OFF

4. Touch correct number for setting.

(10) QUICK DEFROST

1. Touch STOP/CLEAR.

2. Touch QUICK DEFROST.

3. Touch number from 1 to 3
(Touch 1: Ground Beef, Touch 2: Chicken Pieces,

Touch 3: Fish Fillets)

(11) EXPRESS DEFROST

1. Touch STOP/CLEAR.

2. Touch EXPRESS DEFROST.
Three different defrosting levels are provided.
(Ground Meat, Poultry, Steaks/Chops)

3. Enter the weight of your food in decimal
increments from 0.1 to 6.0 pounds.

4. Touch START

5. At beeping, turn food over by following the
instructions in the manual.

6. After turning food over, touch START to resume
defrosting.

(12) TIMED COOKING

1. Touch STOP/CLEAR.

2. Touch COOK TIME.

3. Touch numbers for cooking time.

4. Touch POWER.

5. Touch number for cooking power level.

6. Touch START.

(13) MULTI-STAGE COOKING

1. Touch STOP/CLEAR.

2. Touch COOK TIME.

3. Touch numbers for cooking time.

4. Touch POWER.

5. Touch number for cooking power level.

6. Repeat steps 2-5 to set 2nd cooking stage.

7. Touch START.

MODEL 721.60483000

-11-

8. PROCEDURE FOR MEASURING MICROWAVE
ENERGY LEAKAGE

A. CAUTIONS

(1) Be sure to check a microwave emission prior to servicing

the oven if the oven is operative prior to servicing.

(2) The service personnel should inform the manufacturer,

importer, or assembler of any certified oven unit found to
have a microwave emission level in excess of
5mW/cm.sq. and 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.

(3) 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

(4) The service personnel should check all surface and vent

openings for microwave emission testing.

(5) 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

• Electromagnetic energy leakage monitor (NARDA 8100B,
HOLADAY HI 1501)

• 600cc glass beaker

• Glass thermometer 100°C

B. MEASURING MICROWAVE ENERGY LEAKAGE

(1) Pour 275±15cc of 20±5°C water in a beaker which is

graduated to 600 cc, and place the beaker in the center
of the oven.

(2) Set the energy leakage monitor to 2,450 MHz and use it

following the manufacturer’s recommended test
procedure to assure correct result.

(3) When measuring the leakage, always use the 2 inch

(5cm) spacer supplied with the probe.
(4) Operate the oven at its maximum output.
(5) Measure the microwave radiation using and

electromagnetic radiation monitor by holding the probe

perpendicular to the surface being measured. (See

Figure 7)

C. 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.

MODEL 721.60483000

-12-

Move probe along shaded area.

Probe scanning speed
less than 2.5 cm/sec.

Figure 7

Figure 6

D. 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
5mW/cm.sq. 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 .sq.

E. 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.

F. 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 1mW/cm.sq. 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.

G. POWER OUTPUT MEASUREMENT

(1) Fill the test beaker with 59 ˚F(15 ˚C) ~ 75 ˚F(24 ˚C) 1 liter tap

water.

(2) Stir the water in the beaker with thermometer ( ˚F or ˚C) and

measure temperature as T1.
(3) Place the beaker on the center of turntable.
(4) Set for one (1) minute and three (3) seconds and operate

the oven at high power.

NOTE: The additional three (3) seconds is to allow the

magnetron to begin generating power.

(5) When the heating is finished, stir the water again with

thermometer and measure the temperature of water as T2.
(6) Subtract T1 from T2, this will give you the temperature rise.
(7) The microwave power output is within specification, if the

temperature rise is as shown below:

Temperature Rise

Line Voltage Degrees ˚F Degrees ˚C

120 V 18.9 ~ 25.2 10.5 ~ 14
108 V Min. 17.5 Min 9.7

(8) Power output will be influenced by line voltage of power

supply. Consequently, correct power output must be

measured within 120V AC ± 1 Volt while unit is operating.

MODEL 721.60483000

-13-

SPECIAL TIP

• This oven used the button head screws.

• When you remove the screws, using the
tamper-resistant Torx driver have a
pin-in-head.

Button Head

(Torx style 2)

-14-

MODEL 721.60483000

9. DISASSEMBLY INSTRUCTIONS

IMPORTANT NOTES:

UNIT MUST BE DISCONNECTED FROM ELECTRICAL
OUTLET WHEN MAKING REPAIRS, RE-PLACEMENTS,
ADJUSTMENTS AND CONTINUITY CHECKS. WAIT AT
LEAST ONE MINUTE, UNTIL THE HIGH VOLTAGE
CAPACITOR IN THE HIGH VOLTAGE POWER
SUPPLY HAS FULLY DISCHARGED. THE CAPACITOR
SHOULD BE DISCHARGED BY USING INSULATED
WIRE - I.E. TEST PROBE CONNECTED TO 10KOHM
RESISTOR IN SERIES TO GROUND. 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 OUT CASE (Figures 8)

(1) Remove three screws from the rear section.
(2) Remove one screw from the side section.
(3) Push the outer case back about 1 inch (3cm).
(4) Lift the case from the set.

B. REMOVING POWER AND CONTROL CIRCUIT

BOARD(Figure 9)

(1) Open the door.
(2) Remove two screws, securing the circuit board.
(3) Disconnect the lead wire from RELAY(RY2) on the

circuit board.

(4) Lift up and pull out control panel assembly carefully

from the cavity.

(5) Disconnect the lead wire from connector(CN1) on the

circuit board.

CAUTION: DISCHARGE THE HIGH VOLTAGE

CAPACITOR BEFORE SERVICING.

(6) Pull down and remove the circuit board from the control

panel.

(7) Remove the F.P.C connector from the terminal socket.

Lift up and pull out control panel

securing screw

ground screw

Remove screw

Figures 9

Figure 8

F.P.C.Connector

Control Panel

Circuit Board

C. DOOR GROSS ASSEMBLY REMOVAL

(1) Open the door.
(2) Remove the choke cover very carefully with a flat-blade

screwdriver.

CAUTION : Be careful not to damage door seal plate by

screwdriver.

(3) Lift up and push the door.

NOTE:

1. After replacing the door, be sure to check that the primary
switch, monitor switch, and secondary switch operate
normally.

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

3. 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.

MODEL 721.60483000

-15-

Remove choke cover

Remove Door

Figure 10