Viking CDMOS200, VMOS200, DMOS200, CVMOS200 User Manual

SERVICE MANUAL

MICROWA VE OVEN

COOK

DMOS200

MODELS

CDMOS200 VMOS200

S72M194DMOS2E

DMOS200 CDMOS200 VMOS200 CVMOS200

(DMOS200 model shown)

In the interest of user-safety the oven should be restored to its original condition and only parts identical to those specified should be used.

WARNING TO SERVICE PERSONNEL: Microwave ovens contain circuitry capable of producing very high voltage and current. Contact with the following parts may result in a severe, possibly fatal, electrical shock. (Inverter unit that includes High Voltage Capacitor, High Voltage Power Transformer, High Voltage Rectifier and Heat sink etc., and Magnetron, High Voltage Harness etc..)

TABLE OF CONTENTS

PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO

AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY ................... INSIDE FRONT COVER

BEFORE SERVICING ...................................................................................................... INSIDE FRONT COVER

WARNING TO SERVICE PERSONNEL ................................................................................................................2

MICROWAVE MEASUREMENT PROCEDURE.....................................................................................................3

FOREWORD AND WARNING................................................................................................................................5

PRODUCT SPECIFICATIONS...............................................................................................................................6

GENERAL INFORMATION ...................................................................................................................................6

OPERATION .........................................................................................................................................................8

TROUBLESHOOTING GUIDE .............................................................................................................................12

TEST PROCEDURE ............................................................................................................................................14

TOUCH CONTROL PANEL ASSEMBLY .............................................................................................................24

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ..................................................................31

PICTORIAL DIAGRAM ........................................................................................................................................37

POWER UNIT CIRCUIT.......................................................................................................................................38

LSI UNIT CIRCUIT...............................................................................................................................................39

PRINTED WIRING BOARD .................................................................................................................................40

PARTS LIST........................................................................................................................................................41

PACKING AND ACCESSORIES .........................................................................................................................45

CVMOS200

Page

Range Corporation

111 Front St., Greenwood, MS 38930

Tel: (888) 845-4641

This document has been published to be used for after sales service only. The contents are subject to change without notice.

DMOS200 CDMOS200 VMOS200 CVMOS200

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.

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.

BEFORE SERVICING

Before servicing an operative unit, perform a microwave emission check as per the Microwave Measurement Procedure outlined in this service manual. If microwave emissions level is in excess of the specified limit, contact Viking Service immediately @ 1-888-845-4641.

If the unit operates with the door open, service person should (1) tell the user not to operate the oven and (2) contact VIKING, plus the Department Of Health, Canada and/or the Food and Drug Administration's Center for Devices and Radiological Health immediately.

Service personnel should inform VIKING of any certified unit found with emissions in excess of 4mW/cm2. The owner of the unit should be instructed not to use the unit until the oven has been brought into compliance.

DANGER CAUTION

HIGH VOLTAGE

Do not energize a microwave oven with the outer case cabinet removed, because a microwave oven generates High Voltage in the circuit.

If you intend to operate the oven employing the high frequency switching power converter circuit, you should take special precautions to avoid an electrical shock hazard.

The high voltage transformer, high voltage capacitor and high voltage diode have energized high voltage potential approx. 8 KV.

The aluminium heat sink is connected to the switching power transistor Collector pole, and has an energized high voltage potential approx. 650V peak.

DO NOT ACCESS THE HIGH VOLTAGE TRANSFORMER, HIGH VOLTAGE CAPACITOR, HIGH VOLTAGE DIODE AND HEAT SINK WHEN THE POWER SUPPLY IS CONNECTED TO AN ELECTRICAL OUTLET.

Notes

CDMOS200 DMOS200 VMOS200 CVMOS200

W ARNING TO SERVICE PERSONNEL

Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts fatal, electrical shock.

(Example) High Voltage Capacitor, High Voltage Power Trans-

former, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc..

Read the Service Manual carefully and follow all instructions.

may result in a severe, possibly

Don't Touch ! Danger High Voltage

Before Servicing

1. Disconnect the power supply cord , and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

WARNING:RISK OF ELECTRIC SHOCK.

DISCHARGE THE HIGH-VOLTAGE CAPACITOR BEFORE SERVICING.

The high-voltage capacitor remains charged about 60 seconds after the oven has been switched off. Wait for 60 seconds and then short-circuit the connection of the highvoltage capacitor (that is the connecting lead of the highvoltage rectifier) against the chassis with the use of an insulated screwdriver.

Whenever troubleshooting is performed the power supply must be disconnected. It may in, some cases, be necessary to connect the power supply after the outer case has been removed, in this event,

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the leads to the primary of the power transformer.

5. Ensure that the leads remain isolated from other components and oven chassis by using insulation tape.

6. After that procedure, reconnect the power supply cord.

When the testing is completed,

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Reconnect the leads to the primary of the power transformer.

5. Reinstall the outer case (cabinet).

6. Reconnect the power supply cord after the outer case is installed.

7. Run the oven and check all functions.

After repairing

1. Reconnect all leads removed from components during testing.

2. Reinstall the outer case (cabinet).

3. Reconnect the power supply cord after the outer case is installed.

4. Run the oven and check all functions.

Microwave ovens should not be run empty. To test for the presence of microwave energy within a cavity, place a cup of cold water on the oven turntable, close the door and set the power to HIGH and set the microwave timer for two (2) minutes. When the two minutes has elapsed (timer at zero) carefully check that the water is now hot. If the water remains cold carry out Before Servicing procedure and re-examine the connections to the component being tested.

When all service work is completed and the oven is fully assembled, the microwave power output should be checked and a microwave leakage test should be carried out.

CDMOS200 DMOS200 VMOS200 CVMOS200

MICROWAVE MEASUREMENT PROCEDURE (CANADA)

After adjustment of the door switches are completed individually or collectively, switch test and microwave leakage test must be performed with survey instrument and test result must be confirmed to meet the requirement of the performance standard for microwave ovens as undermentioned.

A. Requirements:

Every microwave oven shall function in such a manner that when the oven is fully assembled and operating with its service controls and user controls adjusted to yield the maximum output, the leakage radiation, at all points at least 5 cm. from the external surface of the oven, does not exceed:

1) 1.0mW/cm2 with the test load of 275 ± 15 ml of water at an initial temperature 20 ±5oC.

2) 5.0mW/cm

3) 5.0mW/cm

when the outer enclosure is removed with a test load of 275 ± 15 ml of water at an initial temperature 20±5oC.

without a test load.

B. Preparation for testing: Before beginning the actual measurement of leakage, proceed as follows:

1) Make sure that the actual instrument is operating normally as specified in its instruction booklet. Important: Survey instruments that comply with the requirement for instrumentation as prescribed by CSA and NHW performance standard for microwave ovens must be used for testing recommended instruments are , NARDA 8100 and NARDA 8200.

2) Place the oven tray in the oven cavity.

3) Place the load of 275±15 ml of tap water initially at 20±5oC in the center of the oven cavity. The water container shall be a low form of 600 ml beaker with an inside diameter of approx. 8.5 cm (3-1/2 in.) and made of an electrically nonconductive material such as glass or plastic. The placing of this standard load in the oven is important not only to protect the oven, but also to insure that any leakage is measured accurately.

4) Set the cooking control on Full Power Cooking Mode, Close the door and select a cook cycle of several minutes. If the water begins to boil before the survey is completed, replace it with 275 ml of cool water.

C. Leakage test with enclosure installed :

1) Grasp the probe of the survey instrument and hold it perpendicular to the gap between the door and the body of the oven.

2) Move the probe slowly, not faster than 2.5 cm/sec. along the gap, watching for the maximum indication on the meter.

3) Check for leakage at the door screen, sheet metal seams and other accessible positions where the continuity of the metal has been breached (eg., around the switches, indicator, and vents). While testing for leakage around the door pull the door away from the front of the oven as far as is permitted by the closed latch assembly.

4) Measure carefully at the point of highest leakage and make sure that the highest leakage is no greater than 4mW/cm2, and that the secondary interlock switch does turn the oven OFF before any door movement.

C. Leakage test without enclosure:

1) Remove the enclosure (cabinet).

2) Grasp the probe of the survey instrument and hold it perpendicular to all mechanical and electric parts of the oven that is accessible to the user of the oven including, but not limited to, the waveguide, cavity seams, magnetron gap between the door and the body of the oven.

3) Move the probe slowly, not faster than 2.5 cm/sec. along the gap, watching for the maximum indication on the meter.

4) Measure carefully at the point of highest leakage and make sure that the highest leakage is under 5mW/cm2.

CAUTION: Special attention should be given to avoid electrical shock because HIGH VOLTAGE is generated during this test

No Load test

1) Operate the oven without a load and measure the leakage by the same method as the above test procedure " Leakage test with enclosure installed"

2. Make sure that the highest leakage should not exceed 5mW/cm2.

NOTE: After servicing, record data on service invoice and microwave leakage report.

CDMOS200 DMOS200 VMOS200 CVMOS200

MICROWAVE MEASUREMENT PROCEDURE (USA)

A. Requirements:

1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should not exceed 1mW/cm2 at any point 5cm or more from the external surface of the oven, measured prior to acquisition by a purchaser, and thereafter (through the useful life of the oven), 5 mW/cm2 at any point 5cm or more from the external surface of the oven.

2) Safety interlock switches: Primary interlock relay switch shall prevent microwave radiation emission in excess of the requirement as above mentioned. Secondary interlock relay and door sensing switch shall prevent microwave radiation emission in excess of 5 mW/cm2 at any point 5cm or more from the external surface of the oven.

B. Preparation for testing: Before beginning the actual measurement of leakage, proceed as follows:

1) Make sure that the actual instrument is operating normally as specified in its instruction booklet.

Important: Survey instruments that comply with the requirement for instrumentation as prescribed by the performance standard for microwave ovens, 21 CFR 1030.10(c)(3)(i), must be used for testing.

2) Place the oven tray in the oven cavity.

3) Place the load of 275±15 ml (9.8 oz) of tap water initially at 20±5

C (68OF) in the center of the oven cavity. The water container shall be a low form of 600 ml (20 oz) beaker with an inside diameter of approx. 8.5 cm (3-1/2 in.) and made of an electrically nonconductive material such as glass or plastic. The placing of this standard load in the oven is important not only to protect the oven, but also to insure that any leakage is measured accurately.

4) Set the cooking control on Full Power Cooking Mode.

5) Close the door and select a cook cycle of several minutes. If the water begins to boil before the survey is completed, replace it with 275 ml of cool water.

C. Leakage test:

Closed-door leakage test (microwave measurement):

1) Grasp the probe of the survey instrument and hold it perpendicular to the gap between the door and the body of the oven.

2) Move the probe slowly, not faster than 1 in./sec. (2.5 cm/sec.) along the gap, watching for the maximum indication on the meter.

3) Check for leakage at the door screen, sheet metal seams and other accessible positions where the continuity of the metal has been breached (eg., around the switches, indicator, and vents). While testing for leakage around the door, pull the door away from the front of the oven as far as is permitted by the closed latch assembly.

4) Measure carefully at the point of highest leakage and make sure that the highest leakage is no greater than 4mW/cm2, and that the primary interlock switch/secondary interlock relay does turn the oven OFF before any door movement.

NOTE: After servicing, record data on service invoice and microwave leakage report.

SERVICE MANUAL

VIKING RANGE CORPORATION

MICROWAVE OVENS

DMOS200 CDMOS200 VMOS200 CVMOS200

FOREWORD

This Manual has been prepared to provide Viking Service Personnel with Operation and Service Information for the Viking Microwave Ovens, DMOS200, CDMOS200, VMOS200, CVMOS200 .

It is recommended that service personnel carefully study the entire text of this manual so that they will be qualified to render satisfactory customer service.

CDMOS200 DMOS200 VMOS200 CVMOS200

PRODUCT DESCRIPTION

GENERAL INFORMATION

OPERATION

TROUBLESHOOTING GUIDE AND TEST PROCEDURE

Check the interlock switches and the door seal carefully. Special attention should be given to avoid electrical shock and microwave radiation hazard.

WARNING

Never operate the oven until the following points are ensured: (A) The door is tightly closed. (B) The door brackets and hinges are not defective. (C) The door packing is not damaged. (D) The door is not deformed or warped. (E) There is no other visible damage with the oven.

Servicing and repair work must be carried out only by trained service personnel.

DANGER

Certain initial parts are intentionally not grounded and present a risk of electrical shock only during servicing. Service personnel - Do not contact the following parts while the appliance is energized; High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness; If provided, Vent Hood, Fan assembly, Cooling Fan Motor.

All the parts marked “*” on parts list are used at voltages more than 250V.

Removal of the outer wrap gives access to voltage above 250V.

TOUCH CONTROL PANEL

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

WIRING DIAGRAM

PARTS LIST

All the parts marked “∆” on parts list may cause undue microwave exposure, by themselves, or when they are damaged, loosened or removed.

VIKING RANGE CORPORATION

111 Front St., Greenwood, MS 38930

Tel: (888) 845-4641

CDMOS200 DMOS200 VMOS200 CVMOS200

SPECIFICATION

ITEM DESCRIPTION

Power Requirements 120 Volts / 13.0 Amperes/1500Watts

60 Hertz Single phase, 3 wire grounded

Power Output 1100 watts (IEC-705 TEST PROCEDURE)

Operating frequency of 2450MHz

Case Dimensions Width 24"

Height 13-3/8" Depth 19-1/8"

Cooking Cavity Dimensions Width 17-3/8"

2.0 Cubic Feet Height 10-1/2" Depth 18-5/8" Tray Size 15"

Control Complement Touch Control System

Clock ( 1:00 - 12:59 ) Timer (0 - 99 min. 99 seconds)

Microwave Power for Variable Cooking Repetition Rate;

P-HI ................................................. Full power throughout the cooking time

P-90.................................................................... approx. 90% of Full Power

P-80.................................................................... approx. 80% of Full Power

P-70.................................................................... approx. 70% of Full Power

P-60.................................................................... approx. 60% of Full Power

P-50.................................................................... approx. 50% of Full Power

P-40.................................................................... approx. 40% of Full Power

P-30.................................................................... approx. 30% of Full Power

P-20.................................................................... approx. 20% of Full Power

P-10.................................................................... approx. 10% of Full Power

P-0.....................................................No power throughout the cooking time

Sensor option pads, Breakfast pad, Lunch pad, Add a minute pad, Frozen food pads, Beverage pad, Number pad, Timer/Clock pad, Clock pad, Power level pad, Stop/Clear pad, Start touch pad, preset recipes pad, 15 minute dinners pad, warm/hold pad and Defrost pad.

Cavity Light Yes

Safety Standard UL and CUL Listed FCC Authorized

DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J and Canadian Standards Association. Health CANADA.

GENERAL INFORMATION

GROUNDING INSTRUCTIONS

This oven is equipped with a three prong grounding plug. It must be plugged into a wall receptacle that is properly installed and grounded in accordance with the National Electrical Code and local codes and ordinances. In the event of an electrical short circuit, grounding reduces the risk of electric shock by providing an escape wire for the electric current.

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

Electrical Requirements The electrical requirements are a 120 volt 60 Hz, AC only, 15 or 20 amp. fused electrical supply. It is recommended that a separate circuit serving only this appliance be provided. When installing this appliance, observe all applicable codes and ordinances. A short power-supply cord is provided to reduce risks of becoming entangled in or tripping over a longer cord. Where a two-pronged wall-receptacle is encountered, it is the personal responsibility and obligation of the customer to contact a qualified electrician and have it replaced with a properly grounded three-pronged wall receptacle or have a grounding

adapter properly grounded and polarized. If the extension cord must be used, it should be a 3-wire, 15 amp. or higher rated cord. Do not drape over a countertop or table where it can be pulled on by children or tripped over accidentally.

CAUTION: DO NOT UNDER ANY CIRCUMSTANCES CUT OR RE-

MOVE THE ROUND GROUNDING PRONG FROM THIS PLUG.

CDMOS200 DMOS200 VMOS200 CVMOS200

1. One touch door open button. Push to open door.

2. Door latches. The oven will not operate unless the door is securely closed.

3. Removable turntable support.

4. Removable turntable. The turntable will rotate clockwise or counterclockwise.

5. Oven lamp. It will light when oven is operating or door is opened.

6. Oven door with see-through window.

7. Ventilation openings. (Rear)

8. Auto-Touch control panel.

9. Time display: Digital display, 99 minutes 99 seconds.

OVEN DIAGRAM

10.Turn table motor shaft

11.Wave guide cover.

12.Power supply cord

TOUCH CONTROL PANEL

COOK

NOTE: The directed features are disabled after one minute when the oven is not in use. These features are automatically enabled when the door is opened and closed or the STOP/ CLEAR pad is pressed.

(VMOS200 model shown)

CDMOS200 DMOS200 VMOS200 CVMOS200

OPERATION

DESCRIPTION OF OPERATING SEQUENCE

The following is a description of component functions during oven operation.

OFF CONDITION

Closing the door activates the door sensing switch and secondary interlock switch. (In this condition, the monitor switch contacts are opened.) When oven is plugged in, 120 volts A.C. is supplied to the control unit. (Figure O-1).

1. The display will show flashing"WELCOME, PRESS CLEAR" To set any program or set the clock, you must first touch the STOP/CLEAR pad. The display will clear, and " : " will appear.

COOKING CONDITION

Program desired cooking time by touching the NUMBER pads. Program the power level by touching the POWER LEVEL pad and then a Number pad. When the START pad is touched, the following operations occur:

1. The contacts of relays are closed and components connected to the relays are turned on as follows. (For details, refer to Figure O-2)

RELAY CONNECTED COMPONENTS RY-1 oven lamp/turntable motor/fan motor RY-2 power transformer

2. 120 volts A.C. is supplied to the primary winding of the power transformer and is converted to about 3.3 volts A.C. output on the filament winding, and approximately 2370 volts A.C. on the high voltage winding.

3. The filament winding voltage heats the magnetron filament and the H.V. winding voltage is sent to a voltage doubler circuit.

4. The microwave energy produced by the magnetron is channelled through the waveguide into the cavity feedbox, and then into the cavity where the food is placed to be cooked.

5. Upon completion of the cooking time, the power transformer, oven lamp, etc. are turned off, and the generation of microwave energy is stopped. The oven will revert to the OFF condition.

6. When the door is opened during a cook cycle, the monitor switch, secondary switch, door sensing switch, primary switch and secondary interlock relay are activated with the following results. The circuits to the turntable motor, the cooling fan motor, and the high voltage components are de-energized, the oven lamp remains on, and the digital read-out displays the time still remaining in the cook cycle when the door was opened.

7. The monitor switch electrically monitors the operation of

the primary switch and primary and is mechanically associated with the door so that it will function in the following sequence.

1) When the door opens from the closed position, the primary switch, secondary switch, door sensing switch, and secondary interlock relay open their contacts and the monitor switch contacts close.

(2) When the door is closed from the open position, the

monitor switch contacts open first. Then the contacts of the primary switch and door secondary switch close.

If the primary switch and the secondary switch primary contacts are closed when the door is opened, the monitor switch contacts form a short circuit through the monitor fuse, primary switch and secondary switch causing the monitor fuse to blow.

POWER LEVEL P-0 TO P-90 COOKING

When Variable Cooking Power is programmed, the 120 volts A.C. is supplied to the power transformer intermittently through the contacts of relay (RY-2) which is operated by the control unit within a 32 second time base. Microwave power operation is as follows:

VARI-MODE ON TIME OFF TIME Power 10(P-HI) 32 sec. 0 sec.

(100% power) Power 9(P-90) 30 sec. 2 sec.

(approx. 90% power) Power 8(P-80) 26 sec. 6 sec.

(approx. 80% power) Power 7(P-70) 24 sec. 8 sec.

(approx. 70% power) Power 6(P-60) 22 sec. 10 sec.

(approx. 60% power) Power 5(P-50) 18 sec. 14 sec.

(approx. 50% power) Power 4(P-40) 16 sec. 16 sec.

(approx. 40% power) Power 3(P-30) 12 sec. 20 sec.

(approx. 30% power) Power 2(P-20) 8 sec. 24 sec.

(approx. 20% power) Power 1(P-10) 6 sec. 26 sec.

(approx. 10% power) Power 0(P-0) 0 sec. 32 sec.

(0% power)

Note: The ON/OFF time ratio does not correspond with the

percentage of microwave power, because approx. 2 seconds are needed for heating of the magnetron filament.

SENSOR COOKING CONDITION

Using the SENSOR function, food is cooked without figuring time, power level or quantity. When the oven senses enough steam from the food, it relays the information to its microprocessor which will calculate the remaining cooking time and power level needed for best results. When the food is cooked, water vapor is developed. the sensor "senses" the vapor and its resistance increase gradually. When the resistance reaches the value set according to the menu, supplementary cooking is started. The time of supplementary cooking is determined by experiment with each food category and inputted into the LSI. An example of how sensor works: (Potatoes)

1. Potatoes at room temperature. Vapor is emitted very slowly.

CDMOS200 DMOS200 VMOS200 CVMOS200

2. The coil of shut-off relay (RY-1) is energized, the turntable motor are turned on, but the power transformer is not turned on.

3. After about 16 seconds, the cook relay (RY-2) is energized. The power transformer is turned on, microwave energy is produced and first stage is started. The 16 seconds is the cooling time required to remove any vapor from the oven cavity and sensor.

NOTE: During this first stage, do not open the door or touch

STOP/CLEAR pad.

4. When the sensor detects the vapor emitted from the food, the display switches over to the remaining cooking time and the timer counts down to zero. At this time, the door may be opened to stir, turn or season food.

5. When the timer reaches zero, an audible signal sounds. The shut-off relay and cook relay are de-energized and the power transformer, oven lamp, etc. are turned off.

6. Opening the door or touching the STOP/CLEAR pad, the time of the day will reappear on the display and the oven will revert to an OFF condition. When the timer reaches zero, an audible signal sounds.

2.Heat Potatoes. Moisture and humidity is emitted very rapidly. You can smell the aroma as it cooks.

3.Sensor detects moisture and humidity and calculates cooking time and variable power.

Cooking Sequence.

1. Touch one of the SENSOR pads. NOTE: The oven should not be operated on sensor

immediately after plugging in the unit. Wait two minutes before cooking on SENSOR.

CDMOS200 DMOS200 VMOS200 CVMOS200

SCHEMATIC

NOTE: CONDITION OF OVEN

1. DOOR CLOSED

2. CLOCK APPEARS ON DISPLAY

120V AC 60 Hz

COM.

SECONDARY SWITCH

N.C.

MONIT OR SWITCH

N.O.COM.

CAPACITOR 1.0µF AC 2300V

POWER TRANSFORMER

H.V. R ECTIFIE R

MAGN ET RON

PRIMARY SWITCH

N.O.

COM.

MONIT OR

FUSE

0.0033uF/AC 125V

GRN

NOISE SUPPRESSION COIL

LINE CROSS CAPACITOR

0.22uF/AC 250V

NOIS E F ILTER UNIT

LINE BYPAS S CAPACITOR LINE BYPAS S CAPACITOR

0.0033uF/AC 125V

CAVITY

MAGN ET RON

TEMP.

FUSE

CONTROL UNIT

(RY -1)

COM.

TTM

COM.

(RY -2)

N.O.

DOOR SENSING SWITCH

N.O.

SECONDARY INTE RL OCK RELAY

COM.

Figure O-1 Oven Schematic - Off Condition

SCHEMATIC

NOTE: CONDITION OF OVEN

1. DOOR CLOSED

2. COOKING TIME PROGRAMMED

3. VARIABLE COOKING CONTROL "HIGH"

4. "START" PAD TOUCHED

120V AC 60 Hz

COM.

SECONDARY SWITCH

AH SE NSOR

N.C.

MONIT OR SWITCH

N.O.COM.

CAPACITOR 1.0µF AC 2300V

POWER TRANSFORMER

H.V. RE CTIF IER

MAGN ET RON

PRIMARY SWITCH

N.O.

COM.

MONIT OR

FUSE

0.0033uF/AC 125V

GRN

NOIS E S UPP RE SS ION COIL

LINE CROSS CAPACITOR

0.22uF/AC 250V

NOISE FILTER UNIT

LINE BYPASS CAPACITOR LINE BYPASS CAPACITOR

0.0033uF/AC 125V

Figure O-2 Oven Schematic - Cooking Condition

CAVITY

MAGN ET RON

TEMP.

FUSE

CONTROL UNIT

(RY -1)

COM.

TTM

COM.

(RY -2)

N.O.

DOOR SENSING SWITCH

N.O.

SECONDARY INTE RL OCK RELAY

COM.

DESCRIPTION AND FUNCTION OF COMPONENTS

DOOR OPEN MECHANISM

The door is opened by pushing the open button on the control panel, refer to the Figure D-1. When the open button is pushed, the open button pushes up the switch lever, and then the switch lever pushes up the latch head. The latch heads are moved upward and released from latch hook. Now the door will open.

Latch Heads

Door

Door Sensing Switch

CDMOS200 DMOS200 VMOS200 CVMOS200

open, the monitor fuse blows simultaneously with closing of the monitor switch contacts.

CAUTION: BEFORE REPLACING A BLOWN MONITOR

FUSE, TEST MONITOR SWITCH AND PRIMARY SWITCH FOR PROPER OPERATION. (REFER TO CHAPTER "TEST PROCEDURE").

NOT E : MONITOR FUSE, AND MONITOR SWITCH ARE

REPLACED AS AN ASSEMBLY.

TURNTABLE MOTOR

The turntable motor rotates the turntable located on the bottom of the oven cavity, so that the foods on the turntable cook evenly during cooking. The turntable may turn in either direction.

Monitor Switch

Switch Lever

Primary Switch

Secondary Switch

Figure D-1. Door Open Mechanism

PRIMARY SWITCH, SECONDARY SWITCH & DOOR SENSING SWITCH

The primary switch and secondary switch mounted parrallel to each other horizontally in the lower positions of the latch hook, the door sensing switch is mounted horizontally in the upper position of the latch hook. They are activated by the latch head on the door. When the door is opened, the switches interrupt the power to all high voltage components, except the oven lamp . A cook cycle cannot take place until the door is firmly closed thereby activating all interlock switches. The secondary interlock system consists of the door sensing switch and the secondary interlock relay located on the control circuit board.

MONITOR SWITCH

The monitor switch is activated (the contacts opened) by the latch head on the door while the door is closed. The switch is intended to render the oven inoperative, by means of blowing the monitor fuse, when the contacts of the primary switch fail to open when the door is opened.

Functions:

1. When the door is opened, the monitor switch contact close (to the ON condition) due to their being normally closed. At this time the secondary interlock relay, primary switch and secondary switch are in the OFF condition (contacts open) due to their being normally open contact switches.

2. As the door goes to a closed position, the monitor switch contacts are first opened and then the door sensing switch, primary switch and secondary switch contacts close. (On opening the door, each of these switches operate inversely.)

3. If the door is opened, primary switch and contacts fail to

COOLING FAN MOTOR

The cooling fan motor drives a blade which draws external cool air. This cool air is directed through the air vanes surrounding the magnetron and cools the magnetron. This air is channelled through the oven cavity to remove steam and vapors given off from the heating foods. It is then exhausted through the exhausting air vents at the oven cavity.

MONITOR FUSE

1. The monitor fuse blows when the contacts (COM-NO) of the primary switch remain closed with the oven door open and when the monitor switch closes.

2. If the wire harness or electrical components are shortcircuited, this monitor fuse blows to prevent an electric shock or fire hazard.

CAVITY TEMPERATURE FUSE

The cavity temperature fuse located on the top of the oven cavity, is designed to prevent damage to the oven by fire. If the food load is overcooked, by either error in cook time or defect in the control unit, the cavity temperature fuse will open. Under normal operation, the cavity temperature fuse remains closed. However, when abnormally high temperatures are reached within the oven cavity, the cavity temperature fuse will open at 302oF(150oC) causing the oven to shut down. NOTE: This is fuse. It does not reset.

MAGNETRON TEMPERATURE FUSE

The magnetron temperature fuse located near the magnetron is designed to prevent damage to the magnetron if an over heated condition develops in the tube due to cooling fan failure, obstructed air guide, dirty or blocked air intake, etc. Under normal operation, the magnetron temperature fuse remains closed. However, when abnormally high temperatures are reached within the magnetron, the magnetron temperature fuse will open at 302oF(150oC) causing the oven to shut down. NOTE: This is fuse. It does not reset.

CDMOS200 DMOS200 VMOS200 CVMOS200

TROUBLESHOOTING GUIDE

Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected.

When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks. Many of the possible causes of trouble will require that a specific test be performed. These tests are given a procedure letter which will be found in the "Test Procedure "section.

IMPORTANT: If the oven becomes inoperative because of a blown monitor fuse, check the primary switch, and monitor

switch, before replacing the monitor fuse. If the monitor fuse is replaced, the monitor switch must also be replaced. Use part FFS-BA016/KIT as an assembly.

IMPORTANT: Whenever troubleshooting is performed with the power supply cord disconnected. It may in, some cases, be

necessary to connect the power supply cord after the outer case has been removed, in this event,

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the leads to the primary of the power transformer.

5. Ensure that the leads remain isolated from other components and oven chassis by using insulation tape.

6. After that procedure, reconnect the power supply cord.

When the testing is completed

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Reconnect the leads to the primary of the power transformer.

5. Reinstall the outer case (cabinet).

6. Reconnect the power supply cord after the outer case is installed.

7. Run the oven and check all functions.

CDMOS200 DMOS200 VMOS200 CVMOS200

CK = Check / RE = Replace

CONDITION

OFF CONDITION

COOKING CONDITION

SENSOR COOKING CONDITION

TEST PROCEDURE

POSSIBLE CAUSE

AND

DEFECTIVE PARTS

PROBLEM

Home fuse or circuit breaker blows when power cord is plugged into wall receptacle

Monitor fuse blows when power cord is plugged into wall receptacle.

All letters and indicators do not appear in display when power cord

is first plugged into wall outlet.

Display does not operate properly when STOP/CLEAR key is touched. (Buzzer should sound and ":" or time of day should appear in display.)

Oven lamp does not light when door is opened.

Oven lamp does not go out when door is closed.

Oven lamp lights but fan motor and turntable motor do not operate.

Oven does not go into cook cycle when START pad is touched

Oven seems to be operating but little or no heat is produced in oven load. (Food incompletely cooked or not cooked at all at end of cook cycle.)

Oven goes into a cook cycle but extremely uneven heating is produced in oven load (food).

Oven does not cook properly when programmed for Cooking Power 5 mode. (Operates properly on Cooking Power 10 (HIGH) mode.)

Oven goes into COMPU DEFROST but food is not defrosted well.

AH sensor does not end during sensor cooking condition. (Oven does not shut off after a cup of water is boiling by sensor cooking)

Oven stops at 16 sec. after starting

RE RE

ABCDEEF FG H

SHORT IN POWER CORD

SHORT OR OPENED WIRING

MAGNETRON

POWER TRANSFORMER

H.V. RECTIFIER ASSEMBLY

HIGH VOLTAGE CAPACITOR

RE RE

CKICK CKCK

CAVITY TEMPERATURE FUSE

MAGNETRON TEMPERATURE FUSE

PRIMARY OR DOOR SENSING SWITCH

SECONDARY INTERLOCK SYSTEM

MONITOR SWITCH

MONITOR FUSE

OVEN LAMP OR SOCKET

COOLING FAN MOTOR

J K L M N

TURNTABLE MOTOR

TOUCH CONTROL PANEL

WRONG OPERATION

LOW VOLTAGE

DIRTY OVEN CAVITY

KEY UNIT

RELAY (RY1)

COMPU DEFROST

FOIL PATTERN ON PWB.

NOISE FILTER

PROCEDURE

LETTER

A MAGNETRON ASSEMBLY TEST

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

TEST PROCEDURES

COMPONENT TEST

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