Electrolux EI30MH55GBA, EI30MH55GWA, EI30MH55GZA, EI30MH55GSA, EI30MH55GBB Technical & Service Manual

...

Publication #5995524377 September 2008 P/N 316439261

Models

EI30MH55GBA EI30MH55GSA EI30MH55GWA EI30MH55GZA

EI30MH55GBB EI30MH55GSB EI30MH55GWB EI30MH55GZB

1-1

Section 1

Basic Information

This Manual has been prepared to provide Electrolux Service Personnel with Operation and Service Information for following Electrolux Microwave Ovens:

EI30MH55GBA, EI30MH55GSA, EI30MH55GWA, EI30MH55GBB, EI30MH55GSB & EI30MH55GWB

Table of Contents

Basic Information

1-2

Section 1 Basic Information .................................. 1-1

Table of Contents .................................................... 1-2

Safe Servicing Practices ........................................ 1-2

Warnings and Safety Information .......................... 1-3

Precautions To Be Observed Before And During Servicing To Avoid Possible Exposure

To Excessive Microwave Energy............................ 1-5

Before Servicing ...................................................... 1-5

Danger Caution High Voltage ................................ 1-5

Before Servicing ...................................................... 1-6

Servicing the Inverter Unit...................................... 1-7

Microwave Measurement Procedure .................... 1-8

Product Specification.............................................. 1-9

Grounding Instructions .......................................... 1-9

Oven Diagram .......................................................... 1-10

Section 2 Operation

................................................ 2-1

Operating Sequence Description .......................... 2-2

Hot Air Exhaust Ventilation Methods .................... 2-4

Oven Schematic-Off Condition .............................. 2-5

Oven Schematic-Cooking Condition .................... 2-5

Component Descriptions........................................ 2-6

Touch Control Panel Operation.............................. 2-7

Description of LSI.................................................... 2-8

Humidity Sensor Circuit.......................................... 2-11

Section 3 Troub

leshooting and Testing ................ 3-1

Troubleshooting Guide .......................................... 3-2

Troubleshooting Guide Chart ................................ 3-3

Test Procedures ...................................................... 3-4

Section 4 Component

Teardown .......................... 4-1

Servicing .................................................................. 4-2

Precautions for Using Lead-Free Solder .............. 4-3

Warnings .................................................................. 4-4

Hood Louver Removal ............................................ 4-6

Outer Case Removal .............................................. 4-6

Hood Fan Motor Removal ...................................... 4-6

Magnetron Removal ................................................ 4-7

Hood Fan Thermal Cut-out Removal...................... 4-7

Oven Thermal Cut-out Removal ............................ 4-7

Inverter Unit and Fan Motor Replacement............ 4-8

Method for Removing Fan Blade .......................... 4-9

Method for Installing Fan Blade ............................ 4-9

Stirrer Motors Replacement .................................. 4-10

Stirrer Fan Assembly Installation .......................... 4-10

Hood Lamp Sockets Removal................................ 4-10

Oven Lamp and Lamp Socket Removal................ 4-11

Positive Lock ® Connector (No-Case Type).......... 4-11

Control Panel Assembly, Control Unit

and Key Unit Removal ............................................ 4-11

Humidity Sensor Removal...................................... 4-12

Noise Filter Removal .............................................. 4-12

Table Tray Assembly Removal................................ 4-12

Stop Switch, Primary Interlock Switch, Secondary Interlock Switch

and Monitor Switch ................................................ 4-13

Stop Switch, Primary Interlock Switch, Secondary Interlock Switch

and Monitor Switch Adjustment ............................ 4-14

Door Replacement .................................................. 4-15

Section 5

Wire Diagrams ........................................ 5-1

Pictorial Diagram .................................................... 5-2

Power Unit Circuit.................................................... 5-3

LSI Unit Circuit ........................................................ 5-4

Printed Wiring Board .............................................. 5-5

Component Descriptions........................................ 2-6

Touch Control Panel Operation.............................. 2-7

Description of LSI.................................................... 2-8

Humidity Sensor Circuit.......................................... 2-11

Section 6 Parts List ................................................ 6-1

Parts List .................................................................. 6-2

Oven Parts Exploded View .................................... 6-4

Cabinet Parts Exploded View ................................ 6-5

Door Parts Exploded View ...................................... 6-6

Packing and Accessories ...................................... 6-7

Basic Information

1-3

Safe Servicing Practices

Avoid personal injury and/or property damage by observing important Safe Servicing Practices. Following are some limited examples of safe practices:

1. DO NOT attempt a product repair if you have any doubts as to your ability to complete the repair in a safe and satisfactory manner.

2. Always Use The Correct Replacement Parts as indicated in the parts documentation. Substitutions may defeat compliance with Safety Standards Set For Home Appliances. Do not exceed maximum recommended wattage on light bulb replacements. Doing so could blow fuses and/or damage transformers.

3. Before servicing or moving an appliance:

• Remove power cord from the electrical outlet, trip circuit breaker to the OFF position, or remove fuse.

4. Never interfere with the proper operation of any safety device.

5. Use ONLY REPLACEMENT PARTS CATALOGED FOR THIS APPLIANCE. Substitutions may defeat compliance with Safety Standards Set For Home Appliances.

6. GROUNDING: The standard color coding for safety ground wires is GREEN, or GREEN with YELLOW STRIPES. Ground leads are not to be used as current carrying conductors. It is EXTREMELY important that the service technician reestablish all safety grounds prior to completion of service. Failure to do so will create a hazard.

7. Prior to returning the product to service, ensure that:

• All electrical connections are correct and secure.

• All electrical leads are properly dressed and secured away from sharp edges, high-temperature components, and moving parts.

• All non-insulated electrical terminals, connectors, heaters, etc. are adequately spaced away from all metal parts and panels.

• All safety grounds (both internal and external) are correctly and securely connected.

• All panels are properly and securely reassembled.

Basic Information

1-4

THIS SERVICE MANUAL IS INTENDED FOR USE BY PERSONS HAVING ELECTRICAL AND MECHANICAL TRAINING AND A LEVEL OF KNOWLEDGE OF THESE SUBJECTS GENERALLY CONSIDERED ACCEPTABLE IN THE APPLIANCE REPAIR TRADE. ELECTROLUX HOME PRODUCTS CANNOT BE RESPONSIBLE, NOR ASSUME ANY LIABILITY, FOR INJURY OR DAMAGE OF ANY KIND ARISING FROM THE USE OF THIS MANUAL.

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.

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; INVERTER UNIT, HIGH VOLTAGE POWER TRANSFORMER, HIGH VOLTAGE RECTIFIER, HEAT SINK, MAGNETRON, HIGH VOLTAGE HARNESS ETC.; 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 WRAPPER GIVES ACCESS TO VOLTAGE ABOVE 250V. ALL THE PARTS MARKED “Ä” ON PARTS LIST MAY CAUSE UNDUE MICROWAVE EXPOSURE, BY

THEMSELVES, OR WHEN THEY ARE DAMAGED, LOOSENED OR REMOVED.

WARNING

Basic Information

1-5

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 per

formed 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 Electrolux HOME PRODUCTS, INC. immediately. If the unit operates with the door open, service person should 1 ) tell the user not to operate the oven and 2) contact Electrolux HOME PRODUCTS, INC. and Food and Drug Administration's Center for Devices and Radiological Health immediately. Service personnel should inform Electrolux HOME PRODUCTS, INC. 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 and high voltage diode have energized high voltage potential approx. 8 KV. The aluminum heat sink is connected to the switching power transistor collector pole, and has an energized high voltage potential of approx. 650V peak. DO NOT ACCESS THE HIGH VOLTAGE TRANSFORMER , HIGH VOLTAGE DIODE AND HEAT SINK WHEN THE POWER SUPPLY IS CONNECTED TO AN ELECTRICAL OUTLET.

Basic Information

1-6

Before Servicing

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

2. Open the door and block it open.

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. Disconnect the leads to the primary of the inverter unit.

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

5. 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. Reconnect the leads to the primary of the inverter unit.

4. Reinstall the outer case (cabinet).

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

6. 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.

MICROWAVE OVENS CONTAIN CIRCUITRY CAPABLE OF PRODUCING VERY HIGH VOLTAGE AND CURRENT, CONTACT WITH FOLLOWING PARTS MAY RESULT IN A SEVERE, POSSIBLY FATAL, ELECTRICAL SHOCK. (EXAMPLE) INVERTER UNIT THAT INCLUDES HIGH VOLTAGE POWER TRANSFORMER, HIGH VOLTAGE RECTIFIER, HEAT SINK ETC., AND MAGNETRON, HIGH VOLTAGE HARNESS ETC.. READ THE SERVICE MANUAL CAREFULLY AND FOLLOW ALL INSTRUCTIONS.

WARNING

Don't Touch ! Danger High Voltage

Basic Information

1-7

Servicing the Inverter Unit

Microwave Measurement Procedure

A. Requirements:

1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should not exceed 1 mW/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 switch shall prevent microwave radiation emission in excess of the requirement as above mentioned, secondary interlock 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 20o±5C (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 and secondary interlock switch do turn the oven OFF before any door movement.

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

THIS INVERTER UNIT CONTAINS CIRCUITRY CAPABLE OF PRODUCING HIGH VOLTAGE AND HIGH CURRENT. CONTACT WITH ANY PART OF THE HIGH VOLTAGE WILL RESULT IN ELECTROCUTION. DO NOT ACCESS ANY PARTS OF INVERTER UNIT WITH POWER SUPPLY CONNECTED. DO NOT OPERATE INVERTER UNIT ITSELF. IT IS DANGEROUS BECAUSE THIS UNIT CONTAINS HIGH VOLTAGE COMPONENTS.

WARNING

Basic Information

1-8

Product Specification

Item Description

Power Requirements 120 Volts / 12 Amperes

60 Hertz Single phase, 3 wire grounded

Power Output 1200 watts (IEC TEST PROCEDURE)

Operating frequency of 2450MHz

Case Dimensions Width 29-15/16"

Height 17" Depth 15- 9/16"

Cooking Cavity Dimensions Width 22-9/16"

Height 10-9/16"

2.1 Cubic Feet Depth 15"

Hood lamp 2 bulbs, 20W x 2, Incandescent light bulbs

Hood fan Approx. High - 300 C.F.M. / Low - 270 C.F.M.

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 Quick Breakfast, Express Lunch, Dinner Recipes, Popcorn, Reheat, Soften, Melt, Warm, Keep Warm, Cook, Defrost, Power Level, Number selection pads, Power Level pad, Timer/Clock pad, Stop/Clear pad, User Pref, Start Add a Minute pad, Light, Fan

Oven Cavity Light 20W x 1 Incandescent light bulb

Safety Standard UL Listed FCC Authorized

DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J Canadian Standards Association Health CANADA, Industry Canada

Weight Approx. 44 lbs.

Basic Information

1-9

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.

Electrical Requirements

The oven is equipped with a 3-prong grounding plug. DO NOT UNDER ANY CIRCUMSTANCES CUT OR REMOVE THE GROUNDING PIN FROM THE PLUG. The power supply cord and plug must be connected to a separate 120 Volt AC, 60 Hz, 15 Amp or more dedicated line, using a grounded receptacle. The receptacle should be located inside the cabinet directly above the Microwave Oven/Hood system mounting location.

IMPROPER USE OF THE GROUNDING PLUG

CAN RESULT IN A RISK OF ELECTRIC SHOCK.

WARNING

3-Pronged Plug

Grounding Pin

3-Pronged Receptacle

Grounded Receptacle Box

Basic Information

1-10

NOTE: Some one-touch cooking features such as "ADD A MINUTE" are disabled after three minutes 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.

1. Oven door with see-through window.

2. Door hinges.

3. Oven lamp. It will light when oven is operating or door is open.

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

5. One touch door open button

6. Auto-Touch control panel.

7. Timer display: Digital display, 99 minutes 00 seconds.

8. Ventilation openings.

9. Light Cover.

10. Grease filters.

11. Power supply cord

Oven Diagram

901

2-1

Section 2

Operation

2-2

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

OFF CONDITION

Closing the door activates the stop switch, primary interlock 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 "Enjoy your oven, press

clear and press clock". To set any program or set the clock, you must first touch the STOP/CLEAR button. The display will clear, and " : " appears.

COOKING CONDITION

Program desired cooking time touching the NUMBER pads. When the START button 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 RY1 Oven lamp / Fan motor / Stirrer motor RY3, RY4 Hood fan motor

2. 120 volts A.C. is supplied to the inverter unit and

is converted in order to power of the magnetron by the high frequency switching power circuit. The frequency is approx. 33-45 KHz.

3. The filament winding voltage of H.V. transformer

heats the magnetron filament and H.V. winding gives a high voltage approx. 2 KV to activate a voltage doubler circuit. Then approx. 4KV peak voltage power is supplied to the magnetron cathode terminal.

4. The microwave energy produced by the

magnetron is channeled 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 inverter

unit, 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, stop switch, secondary interlock switch and primary interlock switch are activated with the following results.The circuits to the stirrer motor, the cooling fan motor, the turntable motor, and the inverter unit are de-energized,and the touch screen displays the time still remaining in the cook cycle when the door was opened.

7. The monitor switch is electrically monitoring the operation of the secondary interlock switch and primary interlock switch and is mechanically associated with the door so that it will function in the following sequence. (1) When the door opens from a closed

position, the primary interlock switch and secondary interlock switch open their contacts, and then the monitor switch contacts close. And contacts of the relay (RY1) remain closed.

(2) When the door is closed from the open

position, the monitor switch contacts first open and the stop switch contacts open, and then the contacts of the secondary interlock switch and primary interlock switch close.

And contacts of the relay (RY1) open. If the secondary interlock switch and primary interlock switch fail with their contacts closed when the door is opened, the closing of the monitor switch contacts will form a short circuit through the monitor fuse, secondary interlock switch, primary interlock switch and relay (RY1) causing the monitor fuse to blow.

Operating Sequence Description

An example of how the sensor works: (BAKED POTATOES)

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

2. Heat Potatoes. Moisture and humidity is emitted 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. Operate the oven in sensor cooking mode by referring to the operation manual.

NOTE: The oven should not be operated on SENSOR immediately after plugging in the unit. Wait two minutes before cooking on SENSOR.

2. The coil of shut-off relay (RY-1) is energized, the turntable motor, oven lamp and cooling fan motor are turned on, but the inverter unit is not turned on.

3. After about 32 seconds, the cook relay (RY-2) is energized. The power transformer is turned on, microwave energy is produced and first stage is started. The 32 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.

Operation

2-3

VARIABLE COOKING

When Variable Cooking Power is programmed, the 120 volts A.C. is supplied to the inverter unit which is operated by the control unit. Microwave power operation is as follows: The oven can be set for any of 11 power levels: 0% to 100%(HIGH). The variable cooking power less than 40% is programmed at the ratio of ON time and OFF time within 32 sec./ cycle time base. Connection between power setting and ON/OFF time of inverter unit.

OUTPUT POWER SETTING ON TIME OFF TIME Power 100% Power 90% Power 80% Power 70% Continue operation Power 60% Power 50% Power 40% 26 sec. 6 sec. Power 30% 22 sec. 10 sec. Power 20% 16 sec. 16 sec. Power 10% 8 sec. 24 sec. Power 0% 0 sec. 32 sec.

NOTE: The ON/OFF time ratio does not correspond with the percentage of microwave power, because approx. 3 seconds are needed for heating of the magnetron filament.

SENSOR COOKING CONDITION

Using the Sensor cooking function the 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 increases 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 input into the LSI.

MICROWAVE

AH SENSOR

MICROWAVE

Operation

2-4

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 is de-energized and the inverter unit, oven lamp, etc. are turned off.

6. Opening the door or touching the STOP/CLEAR pad, the time of day will reappear on the display and the oven will revert to an OFF condition.

Hot Air Exhaust Ventilation Methods

1. VERTICAL VENTING

For this venting method, hot air rising from the conventional range below is drawn in by the hood fan motor through the grease filters at the right and left sides of the base cover, up through the right and left sides of the oven cavity, then discharged vertically at rear center top of the oven, into the customer's vent system.

2. HORIZONTAL VENTING

The air handing is the same as VERTICAL VENTING except that the final air discharge is directed horizontally out from the top rear of the oven into the customer's vent system.

3. RE-CIRCULATION (INSIDE VENTING)

The air handing is the same as VERTICAL VENTING except that the final air discharge is directed horizontally through the upper front of the oven into the kitchen. In this case, the accessory charcoal filter RK-260 must be provided to filter the air before it leaves the oven.

TO DUCT

: AIR FLOW

HOOD FAN MOTOR

TO DUCT

HOOD INTAKE DUCT R

GREASE FILTER

: AIR FLOW

HOOD FAN MOTOR

: AIR FLOW

HOOD FAN MOTOR

HOOD INTAKE DUCT R

GREASE FILTER

HOOD EXHAUST LOUVER

HOOD INTAKE DUCT R

GREASE FILTER

TO DUCT

CHARCOAL FILTER

Operation

2-5

SCHEMATIC

NOTE: CONDITION OF OVEN

1. DOOR CLOSED

2. CLOCK APPEARS ON DISPLAY

GRO

DER

FUSE

NOISE

DER

20A

DER

DE R

FILTER

YRG

U L B

HOOD MOTOR

RED RED

HOOD FAN THERMAL

CUT OUT

U L B

RED

BLK

KL B

WLY

120VAC 60Hz.

K L B

GRN

GND

SECONDARY INTERLOCK

SWITCH

MOTOR

WHT

RED

NRB

RED BLK

NR B

THW

MONITOR

SWITCH

RED BLK

N.O.COM

DER

KLB

T HW

COM

FA F

RED

AC3

N.C.

WHT

BLU

INVERTER

UL B

UNIT

YRG

ULB

NORT

E NGAM

BRN

RED ORG

BLK

PRIMARY

SWITCH

FAN MOTOR WITH

TEMP.FUSE

GRN

BLK

HUMIDITY SENSOR

N.O.

STOP

SWITCH

DER

NRB

THW

STIRRER

RY1

OVEN LAMP

COM.

WHT

DER

THW

BLU

COM

INTERLOCK

DE R

CUT OUT

L UNIT

LPProNRB

U L B

G R O

LVT

RY5

OVEN LAMP

RY6

RELAY

N. O.

GROroWLY

HOOD

YRG

LAMP

ULB

L B

ULB

OVEN THERM

CONTRO

RY4

RY3

High

T H

Low

HOOD

CAPACITOR

DER

W L Y

DER

NOTES:

1. Circuits / Wire Colors subject to change without notice.

2. Terminal that located to the right side on the lamp socket's back view must be connected to neutral wire.

3. Only certain models use the absolute humidity sensor

Figure O-1. Oven Schematic-Off Condition

SCHEMATIC

NOTE: CONDITION OF OVEN

1. DOOR CLOSED

2. COOKING TIME PROGRAMMED

3. VARIABLE COOKING CONTROL "HIGH"

FUSE

NOISE

D E R

20A

D E

FILTER

YRG

ULB

HOOD MOTOR

RED RED

HOOD FAN THERMAL

CUT OUT

UL B

ULB

RED

BLK

K LB

WLY

120VAC 60Hz.

K L B

GRN

GND

NOTES:

1. Circuits / Wire Colors subject to change without notice.

2. Terminal that located to the right side on the lamp socket's back view must be connected to neutral wire.

3. Only certain models use the absolute humidity sensor

DER

CONTROL UNIT

High

Low

HOOD

CAPACITOR

WLY

OVEN

RY4

RY3

Figure O-2. Oven Schematic-Cooking Condition

THERMA L

CUT OUT

RY6

LP Pr oNRB

HOOD

LAMP

ULB

SECONDARY INTERLOCK

SWITCH

MOTOR

WHT

RED

N RB

RED

BLK

N R B

MONITOR

SWITCH

RED BLK

N.O.COM

DER K LB

THW

COM

RED

AC3

N.C.

WHT

BLU

INVERTER

U L B

UNIT

YRG

ULB

N O RTENGA

BRN

RED ORG

BLK

N.O.

PRIMARY

SWITCH

FAN MOTOR WITH

TEMP.FUSE

GRN

BLK

HUMIDITY SENSOR

STOP

SWITCH

DER

NRB

T H

THW

STIRRER

OVEN LAMP

COM

DER

INTERLOCK

THW

DER

LVT

RY5

OVEN LAMP RELAY

RY1

COM.

N. O.

GROr

o WLY

YRG

WHT

ULB

U LB

ULB

BLU

Operation

2-6

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 open lever, and then the open lever pushes up the latch head. The latch heads are moved upward and released from latch hook. Now the door will open.

STOP, PRIMARY INTERLOCK AND SECONDARY INTERLOCK SWITCHES

The secondary interlock switch is mounted in the lower position of the latch hook and the stop switch is mounted in the upper position of the latch hook. The primary interlock switch is also in the upper position of the latch hook. They are activated by the latch heads on the door. When the door is opened, the switches interrupt the circuit to all components. A cook cycle cannot take place until the door is firmly closed thereby activating both interlock switches.

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 interlock switch and secondary interlock 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 primary interlock switch and secondary interlock switch are in the OFF condition (contacts open) due to

their being normally open contact switches. And the contacts of relay (RY1) are in the ON condition (contacts close).

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

3. If the door is opened, and the primary interlock switch and secondary interlock switch contacts fail to open, the monitor fuse blows simultaneously with closing of the monitor switch contacts.

CAUTION: Before replacing a blown monitor fuse, test the stop switch, primary and secondary interlock switch and monitor switch for proper operation.

NOTE: Monitor fuse and switch are replaced as an assembly

THERMAL CUT-OUT (HOOD )

This thermal cut-out located on the right base plate. It is designed to automatically turn on the hood fan motor whenever the hot air rising from the conventional range below causes the temperature at the thermal cut-out to rise to 140F (60C) or higher, thus removing this hot air from around microwave oven. When the temperature around the thermal cut-out drops to 113F (45C) or lower, the thermal cut-out shuts off the hood fan motor.

THERMAL CUT-OUT (OVEN )

This thermal cut-out is located on the top of the oven cavity. It is designed to prevent damage to the oven unit if the food in the oven catches fire due to overheating produced by improper setting of cooking time or failure of control unit. Under normal operation, the thermal cut-out remains closed. However, the thermal cut-out will open at 293F (145C) causing the oven to shut down.

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 channeled 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.

Figure D-1. Door Open Mechanism

Component Descriptions

Latch heads

Latch hook

Stop switch

Door

Open lever

Primary interlock switch

Monitor switch

Secondary interlock switc

Operation

2-7

HOOD FAN MOTOR

The hood fan motor is a two-speed, single-phase, double pole induction type, requiring a hood fan capacitor. It is located outside the upper rear part of the oven cavity, is to remove, from around the oven, hot air rising from the conventional electric or gas range over which it is installed. This air is then expelled either vertically or horizontally through the customer supplied duct system, or discharged back into the kitchen.

STIRRER MOTOR

The stirrer motors drive the stirrer fans to stir the microwave radiation from the waveguide.

HOOD LAMP

The hood lamps are mounted at the hood lamp angle. The hood lamps can be turned off and on by touching the Light Options pad. And also the brightness can be varied to high or low by touching the Light Options pad.

Touch Control Panel Operation

The touch control section consists of the following units as shown in the touch control panel circuit. (1) Key Unit (2) Control Unit (The Control unit consists of LSI Unit

and Power Unit) The principal functions of these units and the signals communicated among them are explained below.

Key Unit

The key unit is composed of a matrix, signals generated in the LSI are sent to the key unit through P20, P21, P22, P23, P24, P25, P26 and P27. When a key pad is touched, a signal is completed through the key unit and passed back to the LSI through P43, P44, P45 and P46 to perform the function that was requested.

Control Unit

Control unit consists of LSI, power source circuit, synchronizing signal circuit, reset circuit, buzzer circuit, relay circuit indicator circuit, back light circuit and humidity sensor circuit.

1) LSI This LSI controls the key strobe signal, relay driving signal for oven function and indicator signal.

2) Power Source Circuit This circuit generates voltages necessary for the control unit from the AC line voltage. In addition, the synchronizing signal is available in order to compose a basic standard time in the clock circuit.

Symbol Voltage Application

VC -5.0V LSI(IC1)

3) Synchronizing Signal Circuit The power source synchronizing signal is avail able in order to compose a basic standard time in the clock circuit. It incorporates a very small error because it works on commercial frequency.

4) Reset Circuit A circuit to generate a signals which resetting the LSI to the initial state when power is applied.

5) Buzzer Circuit The buzzer is responds to signals from the LSI to emit audible sounds (key touch sound and completion sound).

6) Stop Switch A switch to inform the LSI if the door is open or closed.

7) Relay Circuit To drive the inverter unit, fan motor, stirrer motor, hood motor, and light the oven lamp and hood lamp.

8) Indicator Circuit This circuit consists of 25 segments and 4 common electrodes using a Light Crystal Display.

9) Back Light Circuit A circuit to drive the back light (Light emitting diodes LD1-LD5).

10) Humidity Sensor Circuit This circuit detects moisture of the cooking food to allow its automatic cooking.

11) Inverter Unit Control Circuit This is the circuit to control inverter unit.

Operation

2-8

Description of LSI

LSI The I/O signal of the LSI is detailed in the following table.

Pin No. Signal I/O Description

1-2 VL2-VL1 IN Power source voltage input terminal.

Standard voltage for LCD.

3-5 AN7-AN5 IN Terminal to change cooking input according to the Model.

By using the A/D converter contained in the LSI, DC voltage in accordance with the

Model in operation is applied to set up its cooking constant.

6 AN4 IN Temperature measurement input: MAGNETRON THERMISTOR.

By inputting DC voltage corresponding to thetemperature detected by the thermistor,

this input is converted into temperature by the A/D converter built into the SLI.

7 AN3 OUT Back light circuit(Light emitting diodes) driving signal.

8 AN2 IN To input signal which communicates the door open/close information to LSI.

Door close “H”level signal (0V). Door open “L”level signal (-5V).

9 AN1 IN Humidity sensor input f

This input is an analog input terminal from the humidity sensor circuit, and connected

to the A/D converter built into the LSI.

10 AN0 IN Used for initial balancing of the bridge circuit (humidity sensor). This input is an analog

input terminal from the humidity sensor circuit, and connected to the A/D converter built into the LSI

11 P57 OUT Oven lamp, fan motor stirrer motor and inverter unit driving signal

To turn on and off shut off relay (RY 1). The

square waveformvoltage is delivered to the RY1 driving circuit.

16.7 msec.

H : GND

During cooking

12 P56 OUT Signal to sound buzzer (2.0 kHz).

A: key touch sound.

B: Completion sound.

0.1 sec.

2.0 sec.

13 P50 OUT Terminal not used.

14-18 P54-P50 OUT Used for initial balancing of the bridge circuit (humidity sensor)

19 P47 OUT Power level data output signal for inverter unit.

The power level will be decided by the time ratio

16.7 msec.

of T1 and T2.

20 P46 IN Signal coming from touch key.

When either G1 line on key matrix is touched, a correspondingsignal out of P20 - P27

will be input into P46. When no key is touched, the signal is held at “H”level.

21 P45 IN Signal similar to P46.

When either G2 line on key matrix is touched, a corresponding signal will be input into

P45.

22 P44 IN Signal similar to P46.

When either G3 line on key matrix is touched, a corresponding signal will be input into

P44.

23 P43 IN Signal similar to P46.

When either G4 line on key matrix is touched, a corresponding signal will be input into

P43.

24 INT0 IN

Signal synchronized with commercial power source frequency.

This is the basic timing for time processing of LSI.

16.7 msec.

L : -5V

H : GND

L : -5V

H : GND

L : -5V

H : GND

L : -5V

H : GND

L : -5V

Operation

2-9

Pin No. Signal I/O Description

25 P41 OUT Terminal not used.

26 P40 IN Connected to GND through the pull-downresistor.

27 RESET IN Auto clear terminal.

Signal is input to reset the LSI to the initial state when power is applied.

28 P71 OUT Clock signal is output to a memory IC (IC3).

29 P70 OUT Data signal is output to a memory IC (IC3).

30 XIN IN Internal clock oscillation frequency input setting.

The internal clock frequency is set by inserting the ceramic ﬁlter oscillation circuit with

respect to XOUT terminal.

31 XOUT OUT Internal clock oscillation frequency control output.

Output to control oscillation input of XIN.

32 VSS IN Power source voltage: -5.0V.

VC voltage of power source circuit input.

33 P27 OUT Key strobe signal.