SEARS 721.80042, 721.80049, 721.80044, 721.80043, 721.81043 User Manual

삼 흥

정 판

DIVISION 22

BASIC FIELD MANUAL

FOR

MICROWAVE OVEN

MODEL 721.80042700

721.80049700

721.80044700

721.80043700

721.81043700

June, 2007

MODEL 721.80042

721.80049

721.80044

721.80043

721.81043

CAUTION

SAFETY PRECAUTIONS

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.

TABLE OF CONTENTS

(Page)

SAFETY PRECAUTIONS

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Inside front page

SPECIFICATIONS

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1-1

CAUTIONS

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2-1

INSTALLATIONS

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3-1

OPERATING INSTRUCTIONS

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4-1

CONTROL PANEL

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4-1

CONTROL PANEL INSTRUCTIONS

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4-2

OVERALL CIRCUIT DIAGRAM

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5-1

SCHEMATIC DIAGRAM

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5-1

MATRIX CIRCUIT FOR TOUCH KEY BOARD

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5-2

GENERAL INFORMATION FOR SERVICE

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6-1

GENERAL PRECAUTIONS IN USE

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6-1

TRIAL OPERATION

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6-1

FEATURES AND SPECIFICATIONS FEATURES

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6-1

SERVICE INFORMATION

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7-1

PRECAUTIONS AND REPAIR SERVICE TIPS

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7-1

MICROWAVE LEAKAGE TEST

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7-2

POWER OUTPUT MEASUREMENT

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7-3

DISASSEMBLY INSTRUCTIONS

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7-4

INTERLOCK SYSTEM

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7-12

INTERLOCK CONTINUITY TEST

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7-14

TEST AND CHECKOUT PROCEDURES AND TROUBLE SHOOTING

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7-15

A. TEST PROCEDURES

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7-15

B. CHECKOUT PROCEDURES

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7-18

C. TROUBLE SHOOTING

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7-21

EXPLODED VIEW

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8-1

PART REFERENCE LIST

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9-1

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.

1-1

Rated Power Consumption

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1500W maximum (Microwave oven+Cook top lamps+Ventilation fan)

Microwave Output

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1000W (IEC60705) Adjustable 100W through 1000W, 10 steps

Frequency

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2450 MHz ± 50 MHz

Power Supply

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120 VAC, 60 Hz

Rated Current

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14 Amp. (Microwave oven+Cook top lamp+Ventilation fan)

Magnetron Cooling

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Forced Air Cooling

Rectification

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Rectification Voltage Double Half-Wave

Door Sealing

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Choke System

Safety Devices

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Magnetron Thermal Fuse:

Open at 90°C ± 5°C Fuse(20A) Primary Interlock Switch Secondary Interlock Switch Interlock Monitor Switch

Magnetron

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2M214-161GP

High Voltage Capacitor

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Capacitor: 1.0µF, 2.1 KV AC

High Voltage Diode

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Diode; 350mA, 9.0 KV

Cook top Lamp

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125 V, 30 W

Cavity Lamp

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125 V, 30 W or 40 W

Timer

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

Tray

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Tempered Safety Glass

Overall Dimensions

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/16"(W)x167/16"(H)x1511/16"(D)

Oven Cavity Size

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219/16"(W)x91/4"(H)x141/8"(D)

Effective Capacity of Oven Cavity

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1.6 Cu.ft.

Accessories

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Owner’s Manual & Cooking Guide, Installation Manual, Exhaust Adapter, Exhaust Damper, Mounting Kit and Two Filters, Rotating Ring Assembly.

SPECIFICATIONS

• 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.

• For about 30 seconds after the oven stops, an electric charge remains in the high voltage capacitor. When replacing or checking, you must discharge the high voltage capacitor by shorting across the two terminals with an insulated screwdriver.

• 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.

2-1

CAUTIONS

Unlike other appliances, the microwave oven is high-voltage and high-current equipment. Though it is free from danger in ordinary use, extreme care should be taken during repair.

Gasket

ANTENNA

COOLING FIN

MAGNETRON CHASSIS GROUND

FILAMENT TERMINALS

MAGNETRON

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.

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

PRECAUTIONS ON INSTALLATION

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

single-phase power source with a capacity of 15A or 20A.

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.

3-1

INSTALLATIONS

BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY.

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.

Properly Polarized and Grounded Outlet

Plug with Ground Prong

4-1

OPERATING INSTRUCTIONS

CONTROL PANEL

1. Display. The display includes a clock and

indicators to tell you time of day, cooking time settings, cook powers, quantities, weights and cooking functions selected.

2. Popcorn. Touch this pad to pop popcorn with

the sensor feature. The oven ’s sensor will tell the oven how long to cook depending on the amount of humidity it detects from the popcorn.

3. Pizza. Touch this pad to reheat one or several

slices of pizza without entering a cook time or power.

4. Potato. Touch this pad to cook potatoes without

entering a cook time or power.

5. Dinner Plate. Touch this pad to cook without

entering a cook time or power.

6. Frozen Entree. Touch this pad to cook a 10 - to

20 - ounce (284 to 567 g) frozen entree without entering a cook time or power.

7. Frozen Vegetable. Touch this pad to cook

without entering a cook time or power.

8. Express Defrost. Touch this pad to express

defrost. “GROUND BEEF 1.0 LBS TOUCH START” will appear in the display.

9. Auto Cook. Touch this pad to cook

microwavable foods without entering a cook time or power.

10. Auto Reheat. Touch this pad to reheat

microwavable foods without entering a cook time or power.

11. Hold Warm. Touch this pad to keep hot,

cooked foods safely warm in your oven for up to 99 minutes, 99 seconds. Hold Warm can be used by itself, or it can automatically follow a cooking cycle.

12. Auto Defrost. Touch this pad followed by

Number Pads to thaw frozen meat by weight.

13. Add Minute. Touch this pad to cook for 1

minute at 100% cook power, or to add extra minutes at the set cook power to your cooking cycle.

14. Soften. Touch this pad to soften utter,ice

cream, cream cheese, or frozen juice.

15. Melt. Touch this pad to melt butter or

margarine, chocolate, cheese, or marshmallows.

16. Kitchen Timer. Touch this pad to set the

kitchen timer.

17. Number Pads. Touch number pads to enter

cooking times, cook powers, quantities, weights, or food categories.

18. Clock. Touch this pad to enter the correct time

of day.

19. Turntable On/Off. Touch this pad to turn off

the turntable. “T/TABLE OFF” will appear in the display.

20. START. Touch this pad to start a function.If

you open the door after the oven begins to cook, retouch START.

21. Cook Time. Touch this pad followed by

Number Pads to set a cooking time.

22. Power. Touch this pad after the cook time has

been set, followed by a Number Pad to set the amount of microwave energy released to cook the food. The higher the number, the higher the microwave power or “cooking speed.”

23. STOP. Touch this pad to erase an

incorrect command, cancel a program during cooking, or to clear the Display.

24. Light ( ). Touch this pad to turn the light on

high, night (low) or off.

25. Fan ( ) On/Off. Touch this pad to turn the

fan on or off.

26. Fan ( ) 5 Speed. Touch this pad to choose

one of 5 fan speeds.

27. Auto Off Fan timer. Touch this pad followed by

Number pad to set a time for the fan stopping automatically

NOTE: If you try to enter incorrect instructions, you will not hear any tones. Touch STOP/Clear and re-enter the instructions.

4-2

CONTROL PANEL INSTRUCTIONS

5-1

OVERALL CIRCUIT DIAGRAM

SCHEMATIC DIAGRAM

5-2

MATRIX CIRCUIT FOR TOUCH KEY BOARD

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) 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.

6-1

GENERAL INFORMATION FOR SERVICE

PRELIMINARY

A. SINCE NEARLY 2,100 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 bebelow

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.

(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

SERVICE INFORMATION

PRECAUTIONS AND REPAIR SERVICE TIPS

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.

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

• Check for microwave leakage after every servicing. The power density of the microwave radiation leakage emitted by the microwave oven should not exceed 4 mW/cm2. Always start measuring of an unknown field to assure safety for operating personnel from radiation leakage.

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 (31/2in.)

• 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 center of the turntable.

• 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

MICROWAVE LEAKAGE TEST

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