Sharp Smo1854ds User manual

Microwave Oven Microwave Oven Microwave Oven

Service Manual

Microwave Oven

Model: SMO1854DS

S/M No. : SMO1854DS001

DEC. 2018

Caution

: This document has been published to be used for after sales

service only.

The contents are subject to change without notice.

TABLE OF CONTENTS

PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE

EXPOSURE TO EXCESSIVE MICROWAVE ENERGY ..................................................................................................... 1

PROPER USE AND SERVICE PRECAUTIONS ................................................................................................................ 2

1. FOR SAFE OPERATION.................................................................................................................................. 2

2. FOR SAFE SERVICE PROCEDURES............................................................................................................. 2

SPECIFICATIONS .............................................................................................................................................................. 3

EXTERNAL VIEW............................................................................................................................................................... 3

1. OUTER DIMENSIONS...................................................................................................................................... 3

2. FEATURES DIAGRAM ..................................................................................................................................... 4

3. CONTROL PANEL............................................................................................................................................ 5

INSTALLATION .................................................................................................................................................................. 7

OPERATIONS AND FUNCTIONS...................................................................................................................................... 8

DISASSEMBLY AND ASSEMBLY..................................................................................................................................... 9

INTERLOCK MECHANISM AND ADJUSTMENT............................................................................................................ 16

TROUBLESHOOTING GUIDE.......................................................................................................................................... 17

MEASUREMENT AND TEST ........................................................................................................................................... 21

1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT........................................................................ 21

2. MICROWAVE RADIATION TEST................................................................................................................... 22

3. COMPONENT TEST PROCEDURE .............................................................................................................. 23

WIRING DIAGRAM........................................................................................................................................................... 24

PRINTED CIRCUIT BOARD............................................................................................................................................. 25

1. CIRCUIT CHECK PROCEDURE.................................................................................................................... 25

2. PCB CIRCUIT DIAGRAM ............................................................................................................................... 28

3. P.C.B. COMPONENT NO............................................................................................................................... 29

EXPLODED VIEW AND PARTS LIST.............................................................................................................................. 31

1. DOOR ASSEMBLY......................................................................................................................................... 31

2. CONTROL PANEL ASSEMBLY ..................................................................................................................... 31

3. GUIDE WIND ASSEMBLY.............................................................................................................................. 31

4. TOTAL ASSEMBLY ........................................................................................................................................ 31

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 micro-

wave 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.

ments, 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 USE AND SERVICE PRECAUTIONS

1. FOR SAFE OPERATION

Damage that allows the microwave energy (that cooks or heats the food) to escape will result in poor cooking and may

cause serious bodily injury to the operator.

IF ANY OF THE FOLLOWING CONDITIONS EXIST, OPERATOR MUST NOT USE THE APPLIANCE.

(Only a trained service personnel should make repairs.)

(1) A broken door hinge.

(2) A broken door viewing screen.

(3) A broken front panel, oven cavity.

(4) A loosened door lock.

(5) A broken door lock.

The door gasket plate and oven cavity surface should be kept clean.

No grease, soil or spatter should be allowed to build up on these surfaces or inside the oven.

DO NOT ATTEMPT TO OPERATE THIS APPLIANCE WITH THE DOOR OPEN.

The microwave oven has concealed switches to make sure the power is turned off when the door is opened.

Do not attempt to defeat them.

DO NOT ATTEMPT TO SERVICE THIS APPLIANCE UNTIL YOU HAVE READ THIS SERVICE MANUAL.

2. FOR SAFE SERVICE PROCEDURES

1. If the oven is operative prior to servicing, a microwave emission check should be performed prior to servicing the

oven.

2. If any certified oven unit is found to have excessive emission level 5mW/cm², the service person should;

(a) inform the manufacturer, importer or assembler,

(b) repair the unit at no cost to the owner,

(d) tell the owner of the unit not to use the unit until the oven has been brought into compliance.

3. If the oven operates with the door open, the service person should tell the user not to operate the oven and contact

the manufacturer and CDRH immediately.

CAUTION

This device is to be Serviced only by Properly Qualified Service Personnel. Consult the Service Manual for

Proper Service Procedures to Assure Continued Safe Operation and for Precautions to be Taken to Avoid

Possible Exposure to Excessive Microwave Energy.

CAUTION

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

CONNECTED. ALL INPUT AND OUTPUT MICROWAVE CONNECTIONS. WAVEGUIDE FLANGES AND

GASKETS 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.

SPECIFICATIONS

EXTERNAL VIEW

29.9 15.9

16.3

(Unit : in.)

1. OUTER DIMENSION

POWER SUPPLY 120V AC, 14.7 AMPS, 60Hz SINGLE PHASE WITH GROUNDING

MICROWAVE

INPUT POWER 1700 W

ENERGY OUTPUT 1100 W

FREQUENCY 2,450MHz

OUTSIDE DIMENSIONS (W x H x D) 29.9 x 16.3 x 15.9 in

CAVITY DIMENSIONS (W x H x D) 20.6 x 10.0 x 14.9 in

CAVITY VOLUME 1.8 cu.ft

NET WEIGHT APPROX. 51.1 lbs

TIMER 99 min. 99 sec.

POWER SELECTIONS 10 Levels

1 2 3 4 5 6 7

12 11 10

9 8

1DOOR LATCHES

2WINDOW with METAL SHIELD - Screen allows

cooking to be viewed while keeping microwaves

confined in oven.

3MODEL NUMBER PLATE - Located on the front

wall of the microwave oven.

4CHARCOAL FILTER (behind Vent Grille)

5OVEN LIGHT

6WAVEGUIDE COVER

Protects the microwave outlet from splashes of

cooking foods.

7TOUCH CONTROL PANEL and DIGITAL

DISPLAY - For detailed information on each

feature, see Features Diagram section,

page 5,6.

8HOOD CONTROLS

Vent Fan - Press Turbo, High, Low or Off.

Light - Press On or Off

9DOOR BUTTON - To open the door push the door

open button.

0COOKTOP LIGHT

qGREASE FILTERS

wHANDLE FILTERS - Use to insert Grease Filters.

eMETAL RACK - Use for extra space when cooking

with more than one container at the same time.

rTURNTABLE / GLASS TRAY - Must be in place

on top of roller tray when using the microwave

oven.

tVENTILATION MOTOR - Your microwave oven is

designed for adaptation to the following three types

of ventilation.

(Recirculation ventilation system, Vertical

ventilation system,Horizontal ventilation system)

See installation manual to Select the type of

ventilation required for your installation.

yROLLER GUIDE - Placed first on the bottom of the

microwave and support the glass tray.

2. FEATURES DIAGRAM

3. CONTROL PANEL

4 7

u i

o p

a d

The Touch Control Panel allows you to set the oven controls with the press of a finger.

It’s designed to be easy to use and understand.

◆Each time a pad is pressed, a BEEP will sound.

◆When STOP/CLEAR Pad is pressed during oven operation, the oven

will stop, however, all programmed information is retained. To clear all

information, press the STOP/CLEAR Pad again.

1DISPLAY - Displays time of day, time or power level

being used, cooking mode and instructions.

2FROZEN ENTREE - Press this pad to cook Frozen

Entree. The microwave oven sensor will

automatically adjust the cooking time to the type and

amount of food.

3POTATO - Press this pad to cook Potato. The

microwave oven sensor will automatically adjust the

cooking time to the type and amount of food.

4REHEAT - Press this pad to reheat food. The

microwave oven sensor will automatically adjust the

cooking time to the type and amount of food.

5FROZEN VEGETABLES - Press this pad to cook

Frozen vegetables. The microwave oven sensor will

automatically adjust the cooking time to the type and

amount of food.

6POPCORN - Press this pad to cook prepackaged

microwave popcorn weight 3.5/3.0/1.75 ounces.

7BEVERAGE - Press this pad to reheat a beverage.

8MELT/SOFTEN - Press this pad to melt or soften

Butter, Chocolate, Ice Cream and Cheese.

9CLOCK - Press this pad to enter time of day.

0TURNTABLE On-Off - Press this pad to turn

turntable on or off.

qTIME COOK - Press this pad to set the Microwave

cooking time.

◆Power Level 10 (High) is automatic but lower

heat levels may be programmed.

wKEEP WARM - Press this pad and safely keep food

warm for up to 30 minutes.

eDEFROST - Press this pad to set defrosting time or

defrosting weight.

rPOWER LEVEL - Press this pad if you want to

change from automatic Power Level 10 (High) for

cooking.

tNUMBER PADS - Press these pads to enter

cooking time, defrosting time or weight, time of day,

power level.

yEXPRESS COOK - Press these pads to set 1-6

minutes preset cooking time at 100% power level.

u+30 SEC - Press this pad for 30 seconds instant

"ON" cooking time or to add 30 seconds of cooking

time as the timer is counting down.

iKITCHEN TIMER - Press this pad to use as a

minute timer, delay cooking, hold setting after

cooking.

oSTOP/CLEAR - When pressed once, it pauses the

oven operation. When pressed twice, it resets the

oven and erases all settings (except time of day)

pSTART - After all selections are made, press this

pad to start the oven or timer.

aLIGHT - Press this pad to turn on or off the cooktop

light.

sVENT FAN - Press this pad to turn the fan on turbo,

high, low or off.

dFILTER RESET - Press and hold this pad for 3

seconds to reset time after replacing the filter.

Charcoal filters must be replace every 6 months.

Also press and hold this pad for 3 seconds to

set power save mode. For detailed information

on this feature, see Controls section, page 25

of instruction manual.

Also press and hold this pad for 3 seconds to

set sound on/off. For detailed information on

this feature, see Controls section, page 25 of

instruction manual.

Also press and hold this pad for 3 seconds to

set child safety lock function. For detailed

information on this feature, see Controls

section, page 25 of instruction manual.

This appliance must be grounded. In the event of an electrical short circuit, the grounding plug reduces the risk of electric

shock by providing an escape wire for electric current. This appliance is equipped with a cord having a grounding wire

with a grounding plug. The plug must be plugged into an outlet that is properly installed and grounded.

1. Safety Instructions

This product requires a three prong grounded receptacle. The installer must perform a ground continuity check on the

power outlet box before beginning the installation to insure that the outlet box is properly grounded. If not properly

grounded, or if the outlet box does not meet the electrical requirements noted, (under ELECTRICAL

REQUIREMENTS), a qualified electrician should be employed to correct any deficiencies.

CAUTION: FOR PERSONAL SAFETY, REMOVE HOUSE FUSE OR OPEN CIRCUIT BREAKER BEFORE

BEGINNING INSTALLATION TO AVOID SEVERE OR FATAL SHOCK INJURY. CAUTION:FOR PERSONAL

SAFETY, THE MOUNTING SURFACE MUST BE CAPABLE OF SUPPORTING THE CABINET LOAD, IN

ADDITION TO THE ADDED WEIGHT OF THIS 85 POUND PRODUCT, PLUS ADDITIONAL OVEN LOADS OF UP

TO 50 POUNDS OR A TOTAL WEIGHT OF 135 POUNDS.

CAUTION: FOR PERSONAL SAFETY THIS PRODUCT CANNOT BE INSTALLED TO CABINET

ARRANGEMENT’S SUCH AS AN ISLAND OR A PENINSULA. IT MUST BE MOUNTED TO BOTH A TOP

CABINET AND A WALL.

2. Electrical Requirements

Product rating is 120 volts AC, 60Hertz, 14.7 amps, and 1600 ~1700 watts.

This product must be connected to a supply circuit of the proper voltage and frequency. Wire size must conform to

the requirements of the National Electric Code or the prevailing local code for this kilowatt rating. The power supply

cord and plug should be brought to a separate 20ampere branch circuit single grounded receptacle. The outlet box

should be located near the cord entry point. The outlet box and supply circuit should be installed by a qualified

electrician and conform to the National Electric Code or the prevailing local code.

Power supply cord

a) A short power-supply cord is provided to reduce the risks resulting from becoming entangled in or tripping over a

longer cord.

b) Longer cord sets or extension cords are available and may be used if care is exercised in their use.

c) If a long cord or extension cord is used:

1) The marked electrical rating of the cord set or extension cord should be at least as great as the electrical rating of

the appliance.

2) The extension cord must be a grounding type 3-wire cord, and

3) The longer cord should be arranged so that it will not drape over the counter top or tabletop where it can be pulled

on by children or tripped over unintentionally.

This over-the-range oven was designed for use over ranges no wider than 30inches. It may be installed over

both gas and electric cooking equipment.

✳Please see the Installation Manual for details.

INSTALLATION

GROUNDING INSTRUCTIONS

WARNING

Improper use of the grounding can result in a risk of electric shock.

Consult a qualified electrician or serviceman if the grounding instructions are not completely understood, or if doubt

exists as to whether the appliance is properly grounded, and if it is necessary to use an extension cord, use only a

3-wire extension cord that has a 3-blade grounding plug, and a 3-slot receptacle that will accept the plug on the

appliance. The marked rating of the extension cord shall be equal to or greater than the electrical rating of the

appliance.

WARNING

Do not cut or remove the third (ground) prong from the power cord under any circumstances.

Make sure the oven is properly installed and plugged into the electrical outlet.

NOTE : If “PL-0” is selected, the oven will work with the fan but no power. You can use this level to remove odors.

OPERATIONS AND FUNCTIONS

This section includes useful information about oven operation.

1. Plug power supply cord into a standard 3-pronged 14.7 Amps 120V AC 60Hz power outlet.

2. After placing the food in a suitable container, open the oven door and put it on the glass tray.

The glass tray and roller guide must always be in place during cooking.

3. Close the door. Make sure that it is firmly closed.

4. The oven light is on when the microwave oven is operating.

5. The oven door can be opened at any time during operation by pushing the door open button of control panel.

The oven will automatically stop.

6. Each time a pad is pressed, a BEEP will sound to acknowledge the press.

7. The oven automatically cooks on full power unless set to a lower power level.

8. The display will show “ : 0” when the oven CLOCK is not set.

9. Time clock returns to the present time when the cooking time ends.

10. When the STOP/CLEAR pad is pressed during the oven operation, the oven stops cooking and all information retained.

To erase all information(except the present time), press the STOP/CLEAR pad once more. If the oven door is opened

during the oven operation, all information is retained.

11. If the START pad is pressed and the oven does not operate, check the area between the door and door seal for

obstructions and make sure the door is closed securely. The oven will not start cooking until the door is completely

closed or the program has been reset.

TO SET POWER LEVEL

• The power-level is set by pressing the Power Level pad and number pad. If you wish to use a different power level, press

the POWER LEVEL pad before pressing START pad. Enter the power level desired by pressing the appropriate number

pad. The chart shows the display, the power level and the percentage of power.

PRESS POWER PAD AND NUMBER POWER LEVEL (DISPLAY) APPROXIMATE PERCENTAGE OF POWER

POWER LEVEL + 1 + 0 PL10 100%

POWER LEVEL + 9 PL-9 90%

POWER LEVEL + 8 PL-8 80%

POWER LEVEL + 7 PL-7 70%

POWER LEVEL + 6 PL-6 60%

POWER LEVEL + 5 PL-5 50%

POWER LEVEL + 4 PL-4 40%

POWER LEVEL + 3 PL-3 30%

POWER LEVEL + 2 PL-2 20%

POWER LEVEL + 1 PL-1 10%

POWER LEVEL + 0 PL-0 0%

DISASSEMBLY AND ASSEMBLY

Cautions to be observed when troubleshooting.

Unlike many other appliances, the microwave oven is high-voltage, high-current equipment.

It is completely safe during normal operation.

However, carelessness in servicing the oven can result in an electric shock or possible danger from a short circuit.

You are asked to observe the following precautions carefully.

1. Always remove the power plug from the outlet before servicing.

2. Use an insulated screwdriver and wear rubber gloves when servicing the high voltage side.

3. Discharge the high voltage capacitor before touching any oven components or wiring.

(1) Check the grounding.

Do not operate on a two-wire extension cord.

The microwave oven is designed to be used while earthed.

It is imperative, therefore, to make sure it is earthed

properly before beginning repair work.

(2) Warning about the electric charge in the high voltage capacitor.

For about 30 seconds after the operation stopped and electric

charge remains in the high voltage capacitor.

When replacing or checking parts, short between oven chassis and

the negative high terminal of the high voltage capacitor by using a

properly insulated screwdriver to discharge.

4. When the fuse is blown out due to the operation of the monitor switch;

replace primary interlock switch, secondary interlock switch and inter-

lock monitor switch.

5. After repair or replacement of parts, make sure that the screws are

properly tightened, and all electrical connections are tightened.

6. Do not operate without cabinet.

CAUTION : Service personnel should remove their watches whenever working close to or replacing the magnetron.

WARNING : When servicing the appliance, exercise care when touching or replacing high potential parts because

of electrical shock or exposing microwave. These parts are as follows - HV Transformer, Magnetron,

HV Capacitor, HV Diode.

CABINET AS

GRILLE AIR

PROTECTOR WIRE

PLATE *B AS

COVER MOTOR CONDENSOR

1. To remove cabinet and plate *b assembly

1) Remove the microwave oven from its mounting location and set it on a protected (padded) work surface.

2) Remove the 3 screws from the top of the microwave oven that secure the vent grille to the oven, and pull the top of

the vent grille out so the tabs are from their slots, and remove it.

3) Remove 2 screws from the cover motor condensor.

4) Remove the remaining 17 screws from the top side and rear of the cabinet.

Slide the cabinet back and unhook it from the side tabs, then slide the power cord into the cabinet, and lift the cabinet

off the oven.

5) Remove the 3 screws from the bottom of the microwave oven that secure the plate *b assembly to the oven, and

disconnect housing of cooktop light, and remove plate *b assembly.

Proceed to the section for the component you wish to service.

2. To remove door assembly

1) Open the door and remove the stopper door.

2) Lift the door and remove it.

CABINET AS

GRILLE AIR

PROTECTOR WIRE

PLATE *B AS

COVER MOTOR CONDENSOR

STOPPER DOOR

NOTE : After replacing the door assembly, perform a check of correct alignment with the hinge and cavity front plate.

3. Replace cooktop light

When replacing the cooktop light, make sure you allow

the cooktop lights to cool down and wear gloves to avoid

injury from the heat of the lamps.

1) Unplug the oven or turn off the power at the main

power supply.

2) Remove the screw from the light cover and lower the

cover until it stops.

3) Remove the screw of the LED Light secured to the

Cover and pull out connectors.

4) Replace with 1.0-watt LED light available from your

authorized dealer and secure with screw.

You can purchase LED cooktop light from

1-800-BE-SHARP.

5) Reverse the above steps for reassembly.

4. Replace oven light

When replacing the internal oven light, make sure you

allow oven light to cool down and wear gloves to avoid

injury from the heat of the lamp.

1) Unplug the oven or turn off the power at the main

power supply.

2) Remove the vent grille mounting 3 screws and open

the door.

3) Slide the grille air to the left, then pull it straight out.

4) Remove the charcoal filter, if present

5) Pull the hook a little and remove light cover.

6) Push the right hook holding the oven light to the right

side and remove the LED light.

7) Replace with 0.4-watt LED light available from your

authorized dealer.

You can purchase Oven Light from

1-800-BE-SHARP.

8) Reverse the above steps for reassembly.

LIGHT COVER BULB LIGHT

LIGHT COVER LED LIGHT

CHARCOAL FILTER

5. To remove control panel assembly and PCB

1) Unplug the oven or turn off the power at the main power supply.

2) Remove the vent grille mounting 3 screws and open the door.

3) Slide the grille air to the left, then pull it straight out.

4) Remove a screw secured to the control panel assembly.

5) Pull out the connectors from the PCB.

6) Remove 5 screws of PCB.

7) Reverse the above steps for reassembly.

A00

1) Remove the screw which secure the control panel and draw forward the control panel assembly.

2) Remove 5 screws which secure the PCB assembly.

3) Pull out the PCB assembly from the control panel.

4) Disconnect membrane tail from the connector of the PCB assembly.

5) Remove the PCB from the control panel as.

6) Remove the membrane, lever door open, spring button and button door open from the control panel.

7) Reverse the above steps for reassembly.

NO PART CODE PART NAME Q'TY REMARK

B01 9KC35116-0043300 DECORATOR BUTTON 1

B02 9KC35169-0030200 BUTTON DOOR OPEN 1

B03 9KC441G430171 SPRING DOOR BUTTON 2

B04 9KC35116-0043200 DECORATOR C-PANEL *U 1

B05 9KC35116-0043100 DECORATOR C-PANEL *T 1

B06 9KC65192-0030000 SWITCH MEMBRANE 1

B07 9KC35167-0110800 CONTROL-PANEL 1

B08 9KC35168-0000500 BACK-PLATE AS 1

B09 9KC35137-0003100 LEVER DOOR OPEN 1

B10 9KC40303-0115400 MWO PCB MAIN ASSY 1

B11 9KC7122401211 SCREW TAPPING 4

6. To remove guide wind parts.

C00

1) Remove 3 screws for grounding and for fixing to Oven cavity.

2) Remove the noise filter from the guide wind.

3) Pull the fan from the motor shaft.

4) Remove 2 screws which secure the motor shaded pole.

5) Remove the motor shaded pole.

6) Reverse the above steps for reassembly.

NO PART CODE PART NAME Q'TY REMARK

C01 9KC7121402511 SCREW TAPPING 2

C02 9KC3963822200 MOTOR SHADED POLE 1

C03 9KC35125-0024100 GUIDE WIND 1

C04 9KC3511800100 FAN 1

C05 9KC3518608000 NOISE-FILTER 1

C06 9KC7S312X40A1 SCREW SPECIAL 1

7. To remove high voltage capacitor.

1) Remove the screw which secure the grounding ring

terminal of the H.V. diode and the capacitor holder.

2) Remove the H.V. diode from the capacitor holder.

3) Reverse the above steps for reassembly.



High voltage circuit wiring

8. To remove magnetron.

1) Pull out two terminals from the thermostat of

magnetron.

2) Remove a screw which secure the magnetron.

3) Remove the magnetron.

4) Remove the screws which secure the thermostat.

4) Reverse the above steps for reassembly.

Metallic

gasket

plate

Magnetron

antenna

Cooling fin Filament

terminal

Wave guide Magnetron antenna

Metallic

asket plate

Metallic

gasket

plate

Magnetron

antenna

Cooling fin

Filament

terminal

NOTE : Never install the magnetron without the metallic gasket plate which is packed with each magnetron to prevent

microwave leakage. Whenever repair work is carried out on magnetron, check the microwave leakage. It shall

not exceed 4mW/cm² for a fully assembled oven with door normally closed.

9. To remove wind guide assembly.

1) Remove the screw for grounding.

2) Remove the noise filter from the wind guide.

3) Remove the screw which secure the wind guide assembly.

4) Draw forward the wind guide assembly.

5) Pull the fan from the motor shaft.

6) Remove two screws which secure the motor shaded pole.

7) Remove the motor shaded pole.

8) Reverse the above steps for reassembly.

10. To remove H.V.transformer.

1) Remove four screws holding the H.V.transformer.

2) Remove the H.V.transformer.

3) Reverse the above steps for reassembly.

INTERLOCK MECHANISM AND ADJUSTMENT

The door lock mechanism is a device which has been specially designed to completely eliminate microwave radiation when

the door is opened during operation, and thus to perfectly prevent the danger resulting from the leakage of microwave.

(1) Primary interlock switch

When the door is closed, the hook locks the oven door. If the door is not closed properly, the oven will not operate.

When the door is closed, the hook pushes the button of the microswitch. Then the button of the primary interlock switch

bring it under “ON” condition.

(2) Secondary interlock switch and interlock monitor switch

When the door is closed, the hook pushes the lock lever downward. The lock lever presses the button of the interlock

monitor switch to bring it under “OFF” condition and presses the button of the secondary interlock switch to bring it under

“ON” condition.

(3) Adjustment steps

a) Loosen the mounting screw.

b) Adjust interlock switch assembly position.

Actuation distance of primary and secondary interlock switch can be adjusted up tp 0.7mm.

c) Make sure that lock lever moves smoothly after adjustment is completed.

d) Completely tighten all mounting screws.

DOOR CLOSED DOOR OPEN

ADJUSTMENT :

Interlock monitor switch

When the door is closed, the interlock monitor switch should be “OFF” condition before other switches are closed.

When the door is opened, the interlock monitor switch should be “ON” condition after other switches are opened.

NOTE :

1) Service personnel have to reconnect and check continuity of Monitor Circuit.

2) Service personnel have to replace all monitored safety interlocks after monitored interlock failure.

3) Microwave emission test should be performed after adjusting interlock mechanism or replacing of all monitored safety

interlocks after monitored interlock failure.

If the microwave emission exceed 4mW/cm², readjust interlock mechanism.

TROUBLESHOOTING GUIDE

(TROUBLE 1) Oven does not operate at all ; any inputs can not be accepted.

Following the procedures below to check if the oven is defective or not.

1. Check grounding before trouble checking.

2. Be careful of the high voltage circuit.

3. Discharge the high voltage capacitor.

4. When checking the continuity of the switches, fuse or high voltage transformer, disconnect one lead wire from these parts

and check continuity with the AC plug removed. To do otherwise may result in a false reading or damage to your meter.

NOTE :

When electric parts are checked, be sure the power cord is not inserted the wall outlet.

Check wire harness, wiring and connections of the terminals and power cord before checking the parts

listed below.

CONDITION CHECK

Check continuity of interlock

monitor switch with door closed

Check continuity of of primary

interlock switch contact with door

partially open until interlock

monitor switch contact close

Malfunction of

interlock

monitor switch

Shorted

contacts of

primary

interlock switch.

RESULT

Continuity

No Continuity

Replace fuse

CAUSE REMEDY

Replace

(NOTE 1)

Fuse blows.

Replace

(NOTE 1)

Defective low

voltage

transformer

0Ω or infinite

Approx.

207~306

(normal)

Replace

Check continuity of primary

winding of low voltage

transformer

Defective high

voltage

capacitor

Normal Replace

Disconnect one side of the lead

wire connected form high

voltage transformer to the high

voltage capacitor and operate

the unit

Continuity

Defective high

voltage

transformer

Fuse again

blows

Replace

CONDITION CHECK

Check continuity of primary

interlock switch

Malfunction of

primary interlock

switch

RESULT

Continuity

CAUSE REMEDY

Adjust or

replace

Turn table

motor and

oven lamp

do not turn

Check continuity of secondary

interlock and D.O.M switch

Malfunction of

secondary

interlock

switch

Continuity

Adjust or

replace

Check D.C. voltage being

supplied to RELAY (RY3) coil

Defective touch

control circuit

0 V Replace

Faulty contacts of

RELAY (RY3) or

open relay coil

Approx.

15 VDC

Replace

NOTE 1

All these switches must be replaced at the same time, please refer to “Interlock Mechanism And Adjustment”.

Whenever safety interlock switches are replaced: check the wiring color, the connection of monitor switch, and

perform the electrical continuity of interlock switches and microwave radiation emission test.

(TROUBLE 2) Display shows all figures selected, but oven does not start cooking, even though desired program and

time are set and the START pad is pressed.

CONDITION CHECK

Check continuity of magnetron Defective

magnetron

RESULT

Continuity

CAUSE REMEDY

Replace

Outlet has

proper

voltage Fuse

does not

blow.

Display do not indicate

countdown

Malfunction of

secondary

interlock switch

Replace

Check continuity of

power supply cord

Open power

supply cord

Continuity

Replace

Defective touch

control circuit

Normal Replace

(TROUBLE 3) No microwave oscillation even though fan motor rotates.

CONDITION CHECK RESULT

Check continuity of high

voltage capacitor terminals

with wires removed

Continuity

CAUSE

Defective high

voltage

transformer

REMEDY

Replace

microwave

oscillation

Check continuity of high voltage

rectifier in forward and backward

direction with DC megger

Continuity in

backward

direction

Defective high

voltage rectifier

Replace

Connect megger leads to

magnetron terminal and

magnetron body

Continuity Defective

magnetron

Replace

Check resistance of primary and

secondary coil of high voltage

transformer

0 Ω or ∞ Defective high

voltage

transformer

Replace

Check continuity of magnetron

with wires removed

Continuity Defective

magnetron

Replace

Check continuity of filament

terminal of high voltage

transformer

Continuity Defective high

voltage

transformer

Replace

Check D.C. voltage being

supplied to RELAY (RY1) coil

0 V

Defective touch

control circuit

Replace

Approx

15 VDC

Faulty

contacts or

RELAY (RY1)

or open

relay coil

Replace

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