Sharp Microwave Oven R 8580 Users Manual Unknown

SHARP SERVICE MANUAL

S9706R8580J//

CONVECTION

MICROWAVE OVEN

TAME OF CONTENTS

PRECAUTIONS Page

..........................................................................................................

FOREWORD INSIDE FRONT COVER

....................................................................................................................................................... I

THUMB INDEX ..................................................................................................................................................

PRODUCT DESCRlPTlON I

OPERATION ............................................................................................................................... 2

....................................................................................................................................................... 4

SERVlClNG .....................................................................................................................................................

TOUCH CONTROL PANEL ASSEMBLY 11

.....................................................................................................

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE 22

MICROWAVE MEASUREMENT PROCEDURE ..................................................... 30

PICTORIAL DIAGRAM .......................................................................................... 35

..................................................................................................................................

CONTROL PANEL CiRCUlT 36

PRlNTED WIRING BOARD ......................................................................................................................... 37

PARTS LIST .......................................................................................................................... 38

....................................................................................................................................................

PACKING AND ACCESSORIES 39

................................................................................................................... 47

SHARPCORPORATION

R -8680

SERVICE MANUAL

SHARP

CONVECTION MICROWAVE OVEN

R-8580

FOREWORD

This Manual has been prepared to provide Sharp Corp. Service

Personnel with complete Operation and Service Information for

the SHARP CONVECTION MICROWAVE oven, R-8580.

It is recommended that service personnel carefully study the

entire text of this manual so they will be qualified to render

satisfactory customer service.

Check interlock switches and door seal carefully. Special at-

tention should be given to avoid electrical shock and microwave

radiation hazard. (RD36102U)

CAUTION

MICROWAVE RADIATION

Personnel should not ,be exposed to the microwave energy

which ‘may radiate from the magnetron or other microwave

generating devices if it is improperly used or connected. All

input and output microwave connections, waveguides,flanges

and gaskets must be secured. Never operate the device without

a microwave energy absorbing load attached. Never look into

an open waveguide or antenna while the device is energized.

Note( Parts List) : The parts marked ,,+I’ are used in voltage

more than 25OV. (RD36202U)

SHARPCORPORATK)N

OSAKA, JAPAN

1

(RD37201 U)

PRODUCT DESCRIPTION

R-8580

PRODUCT DESCRIPTION

ITEM

Power Requirements

Power Consumption

Power Output

Convection Heater Power Output

Case Dimensions

Cooking Cavity Dimensions

Control Complement

Set Weight

SPECIFICATION

DESCRIPTION

240 Volts

50 Hertz

Single phase, 3 wire earthed

14OOW (Microwave)

1600W (Convection)

700 watts normal of RF microwave energy (2 liter water load)

Operating frequency of 2450M Hz

1.500 Watts

Width 627mm

Height 407mm

Depth 500mm

Width 395mm

Height 253mm

Depth 422mm

Touch Control System

Clock( I:00 - 12:59 )

Timer (0 - 99 min. 99sec. )

Microwave Power for Variable Cooking

Repetition Rate;

HIGH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Full power throughout the cooking time

MED HIGH . . . . . . . . ..*................................. approx. 70% of Full Power

MED . . . ..*............................,.,.................. approx. 50% of Full Power

MED LOW (DEFROST) . . . . . . . . . . . . . . . . . . . . . . approx. 30% of Full Power

LOW ,......,............*.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . approx. 10% of Full Power

No power throughout the cooking time

Ii’Range;

HOLD .,.....*......................

Convection Temperature Contro

40 “C - 250 “C

AUTO START COOKING

INSTANT COOKING

EASY DEFROST COOKING

CONVECTION COOKING

SENSOR COOKING

AUTO MATIC MIX COOKING

COMPU COOKING

Approx. 31 .O kg

R-8580

Auto-TouchTM Control Panel

Touch to select sensor cook mode

,&&:::C::P:

Touch to select Compu Cook mode

1 - Fresh vegetables

2 - Frozen vegetables

3 - Baked potatoes

4 - Frozen dinners

5 - Bacon

6 - Chicken preces

7 - Fish fillets

6 - Rice 8 Pasta

9 - Cake

0 - Reheat

1 -Roast beef/lamb

2 - Roast pork

3 - Roast chrcken

4 - Roast turkey

5 -Roast dmner

6

7 - Mixed grill

-Grilled chicken

6 - Bread loaves

9 -Cake layers

0 - Biscuits -.

I 6 180°C

i 7 200% II

4

.EASY DEFROST PAD

Touch to defrost meat by

weight only

INSTANT COOK PAD

Touch once to cook for 1

increase by 1 minute mult

this pad is touched during

cooking.

entering

minute at HIGH or

:iples each time

HIGH/VARIABLE

1 ’ NUMBER AND TEMPERATURE PADS

Touch to enter cooking times, clock time,

convection temperature or to select the

Sensor or Compu Cook categories.

CONVECTION COOKING FUNCTION PADS

Touch to cook for each function

I

VARIABLE COOKING CONTROL PADS

Touch to select microwave power setting. If

not touched, HIGH is automatically selected.

Touch to select food doneness setting for

Compu Cook. If not touched, Med Done is

automatically selected.

/

TIMER/HOLD PAD

Touch to set minute timer or HOLD function

-AUTO START/CLOCK PAD

Touch to set clock or auto start time

,---STOP/CLEAR PAD

TIMER AUTO START

HOLD CLOCK

Touch to erase during programming.

Touch once to stop operation of oven during

cooking;, touch twice to cancel cooking

Touch to start oven after setting programme.

OPERATION

DESCRIPTION OF OPERATING SEQUENCE

The following is a description of component functions

during oven operation. (RD71101 U)

OFF CONDITION

Closing the door activates both door interlock

switches: upper latch switch, lower latch switch and

stop switch. (In this condition, the monitor switch

contacts are opened.)

When oven is plugged in, 240 volts A.C. is supplied to

the relay unit. (Figure O-l). ’

1. The display will show flashing “88:88”.

To set any program or set the clock;- you must first

touch the STOP/CLEAR pad. The display will clear,

and I:00 will appear and count up every minute.

Note: When the door is opened, the oven lamp comes

2. A si;al is input to the control unit, energizing the

coil of shut-off relay (RY6).

RY6 contacts close, completing a circuit to the

damper motor.

The damper motor now operates moving the damper

to the open position, thereby closing the contacts

of the damper switch inputs a signal to the control

unit.

The coil of relay RY6 is de-energized, opening its

contacts, thereby turning off the damper motor.

(RD71207U)

COOKING CONDITION

HIGH COOKING

Program desired cooking time and Variable Cooking

Control by touching the NUMBER pads and the HIGH

pad of the Variable Cooking Control. 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)

2.

3.

4.

RELAY CONNECTED COMPONENTS

RY-1 power transformer

RY-2 oven lamp/turntable motor

RY-3 convection motor

RY-4 convection heater

RY-5 fan motor

RY-6 damper motor

240 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 2043 volts A.C. on the high voltage

winding.

The filament winding voltage heats the magnetron

filament and the H.V. winding voltage is sent to a

voltage doubler circuit.

The microwave energy produced by the magnetron

is channeled through the waveguide into the cavity

feed-box, and then into the cavity where the food

is placed to be cooked.

5.

6.

7 .

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.

When the door is opened during a cook cycle,

monitor switch, upper latch switch, lower latch

switch and stop switch. are activated with the fol-

lowing results. The circuits to the turntable motor,

the cooling fan motor, and the high voltage com-

ponents are deenergized, the oven lamp remains on,

and the digital readout displays the time still re-

maining in the cook cycle when the door was

opened.

The monitor switch is electrically monitoring the

operation of the upper latch switch and is mechan-

ically associated with the door so that it will func-

tion in the following sequence.

(1) When the door opens from a closed position,

the upper latch switch and lower latch switch

open their contacts, and then the monitor

switch contacts close.

If

(2) When the door is closed from the open posi-

tion, the monitor switch contacts first open,

and then the contacts of the upper latch switch

and lower latch switch close.

the common and normal open contacts of upper

latch 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 fuse and

upper latch switch, causing the monitor fuse to blow.

MED HIGH, MED, MED LOW (DEFROST), LOW,

HOLD COOKING

When Variable Cooking Power is programed, the 240

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 sec-

ond time base. Microwave power operation is as fol-

lows:

VARI-MODE ON TIME OFF TIME

HIGH 32 sec. 0 sec.

(100% power)

MED HIGH 24 sec. 8 sec.

(approx. 70% power)

MED 18 sec. 14 sec.

(approx. 50% power)

MED LOW (DEFROST) 12 sec. 20 sec.

(approx. 30% power)

LOW 6 sec. 26 sec.

(approx. 10% power)

HOLD 0 sec. 32 sec.

(0% power)

Note: The ON/OFF time ratio does not correspond

with the percentage of microwave power, be-

cause approx. 2 seconds are needed for heating

of the magnetron filament. (RD71401 U)

R -8580

CONVECTION COOKING CONDITION

PREHEATING CONDITION

Program desired convection temperature by touching

the CONVECTION pad and the temp. pad.

When the START pad is touched, the following oper-

ations occur:

1. The coil of shut-off relays (RY2, RY3 and RY5) are

energized, the oven lamp, cooling fan motor,

turntable motor and convection motor are turned

2. y:k coil of relay (RY6) is energized by the CPU

unit, The damper is moved to the closed position,

opening the damper switch contacts.

The opening of the damper switch contacts sends

a signal to the LSI on the CPU unit de-energizing

the relay (RY6) and opening the circuit to the

damper motor.

3. The coil of heater relay (RY4) is energized by the

CPU unit and the main supply voltage is added to

the convection heater.

4. When the oven temperature reaches the selected

preheat temperature, the following operations oc-

cur:

4-l. The heater relay (RY4) is de-energized by

the CPU unit temperature circuit and

thermistor, opening the circuit to the con-

vection heater.

4-2. The oven will continue to function for 15

minutes, turning the convection heater on

and off, as needed to maintain the selected

preheat temperature.

The oven will shut-down completely after

15 minutes.

CONVECTION COOKING CONDITION

When the preheat temperature is reached, a beep signal

will sound indicating that the holding temperature has

been reached in the oven cavity. Open the door and

place the food to be cooked in the oven.

Program desired cooking time and convection temper-

ature by touching the NUMBER pad, CONVECTION

pad and Temperature pad.

When the START pad is touched, the following oper-

ations occur:

1.

2.

3.

4.

The numbers of the digital readout. start the count

down to zero.

The oven lamp, turntable motor, cooling fan motor

and convection motor are energized.

Heater relay (RY4) is energized (if the cavity tem-

perature is lower than the selected temperature)

and the main supply voltage is applied to the con-

vection heater to return to the selected cooking

temperature.

Upon completion of the cooking time, the audible

signal will sound, and oven lamp, turntable motor,

cooling fan motor and convection motor are

de-energized. At the end of the convection cycle,

if the cavity air temperature is above 118 OC., the

circuit to RY5 will be maintained (by the thermistor

circuit) to continue operation of the cooling fan

motor until the temperature drops below 118 OC.,

at which time the relay will be de-energized, turn-

ing off the fan motor. Relay RY3 will however,

open as soon as the convection cycle has ended,

turning off the convection fan motor.This will now

cool and allow the damper door to open.

5. At the end of the convection cook cycle, shut-off

relay (RY6) is energized turning on- the damper

motor. The damper is returned to the open position,

closing the damper switch contacts which send a

signal to the control unit, de-energizing shut-off

relay (RY6).

AUTOMATIC MIX COOKING CONDITION

Program desired cooking time and temperature by

touching the number pads and the LOW MIX/BAKE

or HIGH MIX/ROAST pad

When the START pad is touched, the following oper-

ations occur:

1.

2.

3.

4.

5.

6.

The numbers of the digital readout start the count

down to zero.

The shut-off relay (RY2, RY3 and RY5) are ener-

gized, turning on the oven lamp, turntable motor,

and cooling fan motor.

The shut-off relay (RY6) is energized.

The damper door is closed from the open position.

The heater relay (RY4) is energized, adding the

mains supply voltage to the convection heater.

Now, the oven is in the convection cooking con-

dition.

When the oven temperature reaches the selected

temperature, the following operations occur:

6-l. The power supply voltages is added to the

convection heater and power transformer al-

ternately.

6-2. The convection heater operates through the

heater relay (RY4) contacts and the power

transformer operates through the cook relay

(RYI ) contacts.

6-3. These are operated by the CPU unit to sup-

ply alternately within a 32 second time base,

convection heat and microwave energy.

The relationship between the convection

wave power operations are as follows. and micro-

Note: The ON and OFF time ratio does not correspond

with the percentage of microwave power, be-

cause approx. 2 seconds are needed for heating

of the magnetron filament.

MICROWAVE POWER

- Appmx. 10%

I ‘ON

CONVECTION

TEMPERATURE

- leo°C

t I I

1 I

im I I

ICONVECJ OFF &gjggg&

I

r 32~ i

HIGH MIX

-ROAST

MICROWAVE POWER

- A6wrcuc. 30%

CONVECTION

TEMPERATURE

-200%

R-8580

Note: During alternate Microwave/Convection opera-

tion, the convection heater is energized only if

the cavity temperature drops below the set tem-

perature.

SENSOR COOKING CONDITION

Using the SENSOR COOK function, the foods are

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 in-

creases gradually. When the resistance reaches the

value set according to the menu, supplementary cook-

ing 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:

1. Broccoli at room temperature.

Vapor is emitted very slowly.

2. Heat broccoli. Moisture and humidity is emitted

rapidly. You can smell the aroma as it cooks.

3. Sensor detects moisture and humidity and calcu-

lates cooking time and variable power.

Cooking Sequence.

1. Touch SENSOR COOK pad.

NOTE:The oven should not be operated on SEN-

SOR COOK immediately after plugging in

the unit. Wait five minutes before cooking

on SENSOR COOK.

2. Select desired Sensor setting.

3. Touch START pad.

4.

The coil of shut-off relays(RY2,RY5) are energized,

the oven lamp and cooling fan motor are turned

on, but the power transformer is not turned on,

After about 16 seconds, the cook relay (RYI) 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 re-

move any vapor from the oven cavity and sensor.

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

5.

6.

7.

or touch STOP/CLEAR pad.

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 food,

turn it or season, etc.

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,

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.

COMPU COOK

COMPU COOK will automatically compute the oven

temperature, microwave power and cooking time for

baking, roasting and broiling.

Set the desired program by touching the COMPU

COOK pad, and number pad.

Enter the weight by touching the Number pads

When the START pad is touched, the following oper-

ations occur:

1.

2.

3.

4.

5.

6.

The COOK indicator will light and the Convection

Fan Symbol will rotate.

The cooking time will appear on the display and

start counting down to zero.

The cooking time is adjusted automatically ac-

cording to the weight of the food.

The shut-off relays (RY2, RY3, RY4 and RY5) are

energized, turning on the oven lamp, turntable

motor, cooling fan motor and convection motor.

The power supply voltage is added to the con-

vection heater.

Now, the oven is in the convection cooking mode.

When the oven temperature has reached the pro-

grammed convection temperature, the oven goes

into the programmed cooking mode.

At the end of the COMPU COOK cycle, the damper

is returned to the open position and the oven will

go to the off condition.

The cooling fan will remain on until the oven has

cooled.

EASY DEFROST COOKING

The EASY DEFROST key is a special function key to

defrost meats and poultry faster and better.

EASY DEFROST key has 4 defrost stages.

EASY DEFROST automatically defrosts roast beef, etc.

When EASY DEFROST is selected and the food weight

is entered by using the number pads, the oven will

cook according to the special cooking sequence.

240V-50Hz

G-4

MBA

I

TEMP.

FUSE

142’C

UPPER

LATCH

SWITCH

NC

TEMP.

FUSE

142’C

UPPER

LATCH

SWITCH

? NC

LOWER

I ATI

-. -. .

SWITCH d ^-^^ w. +A-7

l-6

RW

A-5

A

RV6 1

c

I

-

CONVECTION%EATER

POWER TRANSFORMER

I t

MONITOR RESISTOR O.B/2OW MON,TOR SW,TCH

OVEN LAMP

FAN MOTOR

n

MONITOR RESISTOR D.B/2DW MONITOR SWITCH

I, OVEN LAMP

RELAY-UNIT A-3

-______

AC CORD CONNECTION

BRN BROWN

BLU : BLUE

G-Y GREEN AND

YELLOW STRIPE

I17 : SECTIONAL AREA

OF l.Omm’ MIN.

I i

AC CORD CONNECTION

BRN BROWN

BLU BLUE

G-Y GREEN AND I RELAY-UNIT

-_-

/I7

YELLOW STRIPE

SECTIONAL AREA

OF l.Omm’ MIN

SENSOR COOKING

NOTE CONDITION

1 DOOR CLOSED

2 ‘SENSOR COOK”

PAD TOUCHED

3 START’ PAD

HIGH COOKING

LOWER

LATCH

SWITCH

1 DOOR CLOSE0

DAMPER MOTOR

1 DOOR CLOSED

2 COOKING TIME

PROGRAMMED

3 VARIABLE COOKING

- TURNTABLE MOTOR

CONVECTION HEATER

I ; POWER TRANSFORMER

I 1 I

MAGNETRON

A

MAGNETRON

RECTIFIER ,

HIGH VOLTAGE

RECTIFIER HIGH VOLTAGE

RECTIFIER

Figure O-l. Oven Schematic-OFF Condition Figure O-2. Oven Schematic-High and Sensor Cooking Condition

R-8580

240V-50Hz

AC CORD CONNECTION

BRN : BROWN

BLU : BLUE

G-Y : GREEN AND

YELLOW STRIPE

117 : SECTIONAL AREA

OF l.Omm’ MIN.

SCHEMATIC I

NOTE: CONDITION

OF OVEN

1. DOOR CLOSED

2. CONVECTION PAD

TOUCHED

3. DESIRED TEMP. PAD

TOUCHED

4. START PAD TOUCHED

LOWER

LATCH

SWITCH

MONITOR RESISTOR 0.8/20W MONITOR SWITCH

OVEN LAMP a//o

FAN MOTOR

I

B

CON”ECTlON%ATER I

POWER TRANSFORMER

RECTIFIER

1

j !

i

L

CAPACITOR

1.13/i

AC2200V

HIGH VOLTAGE

RECTIFIER

I

TEMP.

FUSE

142°C

UPPER

LATCH

SWITCH

4

NC

4

MAGNETRON

Figure O-3. Oven Schematic-Convection Cooking Condition

8

R -8580

DESCRIPTION AND FUNCTION OF COMPONENTS

THERMISTOR

The thermistor is a negative temperature coefficient

type. The temperature in the oven cavity is detected

through the resistance of the thermistor, and then the

CPU unit causes the heater relay to operate, thus the

current to the convection heater is turned ON/OFF.

OVEN THERMAL CUT-OUT

The oven thermal cut-out located on the bottom side

of the thermal protection plate is designed to prevent

damage to the convection heater unit if an overheated

condition develops in the tube due to cooling fan fail-

ure, obstructed air ducts, dirty or blocked air intake, etc.

Under normal operation, the oven thermal cut-out re-

mains closed. However, when abnormally high tem-

peratures are reached within the heater unit, the oven

thermal cut-out will open, causing the oven to shut

down.

When the oven has cooled temperature, the oven

thermal cut-out closes.

MONITOR SWITCH

The monitor switch is mounted on the upper latch

hook. It is activated (the contacts opened) by the up-

per latch head when the door is closed. The switch is

intended to render the oven inoperative by means of

blowning the fuse when the contacts of the common

and normal open contacts of upper latch switch fail to

open when the door is opened.

Functions:

1.

2.

3.

When the door is opened, the monitor switch con-

tacts close (to the ON condition) due to their being

normally closed. At this time the the common and

normal open contacts of upper latch switch are in

the OFF condition (contacts open) due to their

being normally open contacts switch.

As the door goes to a closed position, the monitor

switch contacts are first opened and then the

common and normal open contacts of upper latch

switch close. (On opening the door, each of these

switches operate inversely.)

If the door is opened during cooking, and the

common and normal open contacts of upper latch

switch fail to open, the monitor fuse blows simul-

taneously with closing of the monitor switch con-

tacts.

CAUTION:BEFORE REPLACING A BLOWN FUSE

TEST THE UPPER LATCH SWITCH AND

MONITOR SWITCH FOR PROPER

OPERATION.(REFER TO CHAPTER “TEST

PROCEDURE”).

AFTER REPLACING FUSE ALSO REPLACE

MONITOR SWITCH.

STOP SWITCH

The stop switch is activated by the lower latch head.

When the door is opened while the oven is in cook

cycle, the stop switch contacts open to de-energize the

relay(RY-l,RY-2,RY-3,RY-4,RY-5).

Then the cook cycle is stopped.

UPPER AND LOWER LATCH SWITCHES

The lower latch switch is mounted in the lower latch

hook and the upper latch switch is mounted in the

upper latch hook.

heads on the door. They are activated by the latch

When the door is opened, the

switches interrupt the’crrcuit to all components except

CPU unit and relay unit and oven lamp. A cook cycle

cannot take place until the door is firmly closed thereby

activating both interlock switches.

P

A ’ UPPER

LATCH

HOOK

Figure D-l. Upper Latch Switch, Lower Latch

Switch, Monitor Switch and Stop Switch

R-8580

The convection heater is located at the left side of the

oven cavity. It is intended to heat air driven by the

convection fan. The heated air is kept in the oven and

force-circulated and reheated by the convection heater.

CONVECTION HEATER Microwave Cooking:

Damper is in the open position, because a portion of

cooling air is channeled through the cavity to remove

steam and vapors given off from the heating foods.

It is then exhausted at the top of the oven cavity into

a condensation compartment.

CONVECTION COOKING SYSTEM

This oven is designed with a hot air heating system

where food is not directly heated by the convection

heater, but is heated by forced circulation of the hot

air produced by the convection heater.

The air heated by the convection heater is circulated

through the convection passage provided on the outer

casing of the oven cavity by means of the convection

fan which is driven by the convection motor. It then

enters the inside of the oven through the vent holes

provided on the left side of the oven. Next,the hot air

heats the food on the turntable and leaves the oven

cavity through the vent in the oven cavity left side wall.

Without leaving the oven, this hot air is reheated by the

convection heater, passes through the convection

passage and enters the inside of the oven cavity again,

in a continuing cycle.

In this way, the hot air circulates inside the oven cavity

to raise its temperature and, at the same time, comes

into contact with the food being cooked.

When the temperature inside the oven cavity reaches

the selected temperature, the convection heater is

de-energized. When the temperature inside the oven

cavity drops below the selected temperature, the con-

vection heater is energized again. In this way, the in-

side of the oven cavity is maintained at approximately

the selected temperature.

When the convection time reaches 0, the convection

heater is deenergzed and the convection fan stops op-

erating and the oven shutts off.

Upon completion of the cooking time, the audible sig-

nal will sound, and oven lamp, turntable motor, cooling

fan motor and convection motor are de-energized. At

the end of the convection cycle, if the cavity air tem-

perature is above 118 OC., the circuit to RY5 will be

maintained (by the thermistor circuit) to continue op-

eration of the cooling fan motor until the temperature

drops below 118 OC., at which time the relay will be

de-energized, turning off the fan motor. Relay RY3 will

however, open as soon as the convection cycle has

ended, turning off the convection fan motor.This will

now cool and allow the damper door to open.

DAMPER OPEN-CLOSE MECHANISM

Usually, the damper is in the open position except

during convection cooking.

Damper position is set automatically by damper motor,

damper switch, motor cam and damper shaft.

These components are operated by a signal that judges

if microwave cooking or convection cooking operation

is selected by the CPU unit.

Convection Cooking:

Damper is in the closed position, so that no hot air will

be allowed to leak out the oven cavity.

Damper Operation

I, When power supply cord is plugged in:

l-l.

1-2.

1-3.

1-4.

1-5.

When power supply cord is plugged in, a sig-

nal is sensed in the control unit, and operates

shut-off relay (RY6).

Contacts of shut-off relay (RY6) close, the

damper motor is energized, opening the

damper door.

When the damper is moved to the open posi-

tion by the damper cam dampe switch is

closed (ON position).

The signal of damper switch is re-sensed in

the control unit and shut-off relay (RY6) is

turned off.

The 240 volts A.C. to the damper motor is

stopped and the motor turns off.

2. When oven is microwave cooking:

Damper is in the open position.

3. When oven is convection cooking:

3-l.

3-2.

3-3.

3-4.

Damper motor is energized by touching the

convection, temperature and START pads.

When damper is in the closed position

(damper switch is OFF), its signal is sensed

by the control unit, and shut-off relay (RY6)

is de-energized.

The damper is held in the closed position

during the convection cooking operation.

At the end of the convection cooking, shut-off

relay (RY6) is energized, and the damper is

returned to the open position.

NOTE: If the damper door is not in the proper position,

closed durin convection or open durning

microwave, the control unit will stop oven op-

eration after 1 minute.

Cooking Mode Operation of Damper

Microwave cooking OPEN

Convection cooking CLOSE

Sensor cooking OPEN

Automatic mix cooking CLOSE

Grill cooking CLOSE

Slow cooking CLOSE

10

SERVICING

TROUBLESHOOTING GUIDE

When troubleshooting the microwave oven, it is

helpfull to follow the Sequence of Operation in per-

IMPORTANT: lf the oven becomes inoperative be-

cause of a blown fuse in the monitor

forming 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.

switch and upper latch switch circuit,

check the monitor switch and upper

latch switch before replacing the fuse.

If the fuse is replaced, the monitor

switch should be replaced at same

time. (RD8’ll OZU)

PROBLEM POSSIBLE CAUSE TEST PROCEDURE OR

CORRECTION

OFF CONDJTION

Home fuse blows when power

cord is plugged into wall recepta- Shorted wire in power cord or wire har-

ness. Replace cord or check wiring.

cle.

Fuse blows when power cord is

plugged into wall receptacle.

Shorted wire in power cord or wire har-

ness. Replace power cord or check

and repair harness.

Defective monitor switch. Procedure F.

88:88 do not appear in display No power at outlet.

when power cord is first plugged Check home fuse.

Blown fuse.

into wall outlet. Procedure G.

Blown magnetron temp. fuse. Procedure H.

Defective thermal cut-out. Procedure I.

Open wire in power cord, wiring harness,

or wrrrng between control panel assembly Replace or repair wiring.

units.

Defective CPU unit. Procedure 0.

Defective relay unit. Procedure N.

Display does not operate properly

when STOP/CLEAR Defective key unit.

key is Procedure P.

touched. (B uzzer should sound Defective CPU unit. Procedure 0.

and time of day should appear in Defective relay unit. Procedure N.

display.) Defective stop switch. Procedure E.

Oven lamp does not light with No power in home.

door opened. Check wall outlet.

, Open wire in power cord or wire harness. , Replace same or repair wir- 1

rng.

Defective oven lamp.

-*

Replace.

Defective upper latch switch. Procedure E.

Blow fuse. Procedure G.

Defective thermal cut-out. Procedure I.

Defective magnetron temp. fuse. Procedure H.

Open or loose wire connection to the Check wiring.

above components.

11

R -8580

PROBLEM POSSIBLE CAUSE TEST PROCEDURE OR

CORRECTION

COOKING CONDITION

Oven lamp does not light in cook Defective shut-off relay (RY2) on relay Procedure N.

cycle. unit.

(Does light when door is opened) Defective CPU unit. Procedure 0.

Oven lamp does not light at all. Burned out bulb. Replace

Open wiring of oven lamp. Check and repair wiring

Oven lamp lights, but turntable Open or loose wiring to turntable motor. Check and repair wiring

motor does not operate. Defective turntable motor. Replace

Turntable motor operates normally Defective cooling fan motor. Replace.

but cooling fan motor does not Defective shut-off relay (RY5) on relay Procedure N.

operate unit.

Open or loose wiring to fan motor Check and repair wiring

MICROWAVE

Oven does not go into a cook cy- Upper latch switch and/or lower latch Procedure E.

cle when START pad is touched. switch defective or out adjustment.

Defective cook relay (RYI ) on relay unit. Procedure N.

Defective CPU unit. Procedure 0.

Defective key unit. Procedure P.

Open or loose wiring to above compo- Check and repair wiring

nents.

Oven seems to be operating but Defective magnetron. Procedure A.

little or no heat is produced in Defective cook relay (RYI ) on relay unit. Procedure N.

oven load.( Food incompletely Defective power transformer. Procedure B.

cooked or not cooked at all at end Defective high voltage rectifier. Procedure C.

of cook cycle.) Defective high voltage capacitor. Procedure 0.

Defective CPU unit. Procedure 0.

Open or loose wiring to above compo- Check and repair wiring

nents.

Oven goes into a cook cycle but Turntable motor does not operate. Replace turntable motor or

extremely uneven heating is check and repair wiring.

produced in oven load(food).

Oven does not cook properly Defective CPU unit. Procedure 0.

when programed for MEDIUM Defective key unit. Procedure P.

etc. cooking powers.

(Operates properly on HIGH) Open or loose wiring to above compo- Check and repair wiring

I nents.

Oven does not cook properly Defective EASY DEFROST function. Refer to EASY DEFROST

when programed in EASY DE- section in operation manual

FROST cooking mode. and check CPU unit.

12

R -8580

PROBLEM POSSIBLE CAUSE TEST PROCEDURE OR

CORRECTION

CONVECTION

r

CONV indicator light but oven

does not go into a cook cycle

when START pad is touched.

CONV indicator lights, but heating

element does not heat.

Temperature in the oven cavity is

lower or higher than preset.

Lower than preset temperature.

Cooling fan motor, turntable mo-

tor and oven lamp run

intermitantly or all the time.

Convection cycle runs 3 minutes

then shuts down.

SENSOR

Defective heater relay(RY4) on relay unit. Procedure N.

Defective key unit. Procedure P.

Defective thermistor. procedure K.

Open wiring in circuit to above compo-

nents. Check and repair wiring.

Defective convection heater. Procedure J.

Defective heater relay(RY4) on relay unit. Procedure N.

Defective CPU unit. Procedure 0.

Open or loose wire connection to the Check and repair wiring.

above components.

Defective convection heater. Procedure J.

Defective CPU unit. Procedure 0.

Defective convection motor. Replace motor.

Defective thermistor. Procedure K.

Defective cooling fan motor. Replace fan motor.

Defective dumper motor. Procedure L.

Defective drive mechanism of convection Check.

fan.

Low power supply voltage. Check voltage.

Thermistor shorted. Procedure K.

Thermistor open. Procedure K.

Oven is in the sensor cooking AH sensor open and/or short. Procedure 0.

condition but AH sensor does not Defective CPU unit.

end stage 1 or does not stop Procedure 0.

0 pen or loose wire connection to the Check and repair wiring.

cooking cycle or the oven stops above components.

soon. AH sensor assembly and/or steam duct Check and repair them.

are not re-installed correctry.

13

R-8580

TEST PROCEDURES

PROCEDURE

LETTER COMPONENT TEST

MAGNETRON ASSEMBLY TEST

DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPO-

NENTS OR WIRING.

To test for an open filament, isolate the magnetron from the high voltage circuit. A continuity

check across the magnetron filament leads should indicate less than 1 ohm.

To test for a shorted magnetron, connect the ohmmeter leads between the magnetron filament

leads and chassis ground. This test should indicate an infinite resistance. If there is little or no

’ resistance, the magnetron is grounded and must be replaced.

Power output of the magnetron can be measured by performing a water temperature rise test.

This test should only be used if above rests do not indicate a faulty magnetron and there is no

defect in the following components or wiring: high voltage rectifier, rectifier, high voltage

capacitor, and power transformer.

MICROWAVE OUTPUT POWER

Microwave output power from the magnetron can be measured by way of substitution, i.e. it can

be measured by using water load how much it can be absorbed by the water load. To measure

the microwave output power in the microwave oven, the relation of calorie and watt is used.

When P(W) heating works for t(second), approximately P x t/4.2 calorie is generated. On the

other hand, if the temperature of the water with V(ml) rises AT ( “C) during this microwave

heating period, the calorie of the water is V x AT.

The formular is as follows;

Pxt/4.2=Vx AT

P(W)=4.2xVx AT/t

Our condition for the water load is as follows:

Water load . . . 2000 ml, Heating time . ..I 20 seconds

P=7Ox AT

Measuring method;

1. Put the water load of two (2) litres on the center of the oven shelf. The water load should

be arranged in two (2) Pyrex beakers, the size of which is one (1) litre, and be placed at right

and left, side by side, on the oven shelf.

2. Measure the temperature of water before heating and also after heating during 120 seconds

by microwave, and calculate the temperature rise. The temperature rise should be the average

of temperature differences measured in each beaker.

3. The output power should be calculated as follows. In case the measuring result is not satis-

factory, execute the measurement several times and judge the result from the synthetic point

of view. Microwave output power should be within + 15% of the nominal one.

Calculation of output power;

Microwave output power . ..P(W)=7Ox AT(%)

AT = ( ATL + ATR) / 2 : average temperature rise

ATL = (TL2 - TLI), ATR = (TR2 - TRI)

TL2 : water temperature after heating in left beaker

TLI : water temperature before heating in left beaker

TR2 : water temperature after heating in right beaker

TRI : water temperature before heating in right beaker

Measuring condition;

As the microwave output is affected by several conditions, the measurement should be made

carefully with following attentions.

1. Initial temperature of salt water should be 10 + 1 “C. Well and quickly stir the water and the

temperature measurement should be done immediately after heating.

2. The graduation of thermometer should be scaled by 0.1 “C at minimum and an accurate mer-

cury thermometer is recommended.

14

R-8680

TEST PROCEDURES (CONT’D)

PROCEDURE

LETTER COMPONENT TEST

3. Water container should be one (1) litre beaker made of Pyrex glass and its diameter approxi-

mately 12 cm.

4. Room temperature should be around 20 “C.

5. Power supply voltage should be specification voltage.

POWER TRANSFORMER TEST

DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPO-

NENTS OR WIRING.

Disconnect the primary input terminals and measure the resistance of the transformer with an

ohmmeter. Check for continuity of the coils with an ohmmeter. On the R x 1 scale, the resistance

of the primary coil should be approx. 1.6 ohm and the resistance of the high voltage coil should

be approximately 74 ohms; the resistance of the filament coil should be less than 1 ohm.

(HIGH VOLTAGES ARE PRESENT TO HIGH VOLTAGE TERMINAL, SO DO NOT ATTEMPT TO

MEASURE THE FILAMENT AND HIGH VOLTAGE.)

C HIGH VOLTAGE RECTIFIER AND RECTIFIER TEST

DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPO-

NENTS OR WIRING.

HIGH VOLTAGE RECTIFIER TEST

Isolate the high voltage rectifier from the circuit. Using the highest ohm scale of the meter read

the resistance across the terminals and observe, reverse the leads to the high voltage rectifier

terminals and observe meter reading. If a short is indicated in both directions, or if an infinite

resistance is read in both directions, the high voltage rectifier is probably defective and should

be replaced.

RECTIFIER TEST

D

Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the resistance

across the terminals, reverse the leads to the rectifier terminals and observe meter reading.

infinite resistance is read in both directions, the rectifier is good. If an

If a short is indicated in either direction, the one is probably defective and should be replaced.

HIGH VOLTAGE CAPACITOR TEST

DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPO-

NENTS OR WIRING.

E

If the capacitor is open, no high voltage will be available to the magnetron. Disconnect input

leads and check for short or open, between the terminals using an ohmmeter.

Checking with a high ohm scale, if the high voltage capacitor is normal, the meter will indicate

continuity for a short time and should indicate approximately IOM R once the capacitor is

charged. If the above is not the case, check the capacitoi’with an ohmmeter to see if it is shorted

between the terminals. If it is shorted, replace the capacitor.

(RD82603U)

SWITCH TEST

Isolate the switch and check the contacts by using an ohmmeter using the following table.

If improper operation is indicated, make the necessary switch adjustment or replacement.

Table: Switch Connection

Connection Common Terminal-Normally Open Terminal

(COM) (NO)

Common Terminal-Normally Close Terminal

Operation (COW (NC)

Plunger released Open circuit Close circuit

Plunger pushed Closed circuit Open circuit

(RD82701U)

15

R-8580

TEST PROCEDURES (CONT’D)

PROCEDURE

LETTER COMPONENT TEST

MONITOR SWITCH TEST

Before performing this test, disconnect oven from power supply and make sure that the upper

latch switch is operating properly referring to the above Switch Test Procedure.

Disconnect the wire lead from the monitor switch (NC) terminal.

Check the monitor switch operation by using the ohmmeter as follows.

When the door is open, the meter should indicate a closed circuit.

When the monitor switch actuater is pushed by a screw driver through the upper latch hole on

the front plate of the oven cavity with the door opened (in this condition the plunger of the

monitor switch is pushed in), the meter should indicate an open circuit.

If improper operation is indicated, replace the defective switch..

After testing the monitor switch, re-connect the wire lead to the monitor switch (NC) terminal.

SCREW.

\

UPPER ’

LACCH

HOLE

G BLOWN FUSE

If the fuse in the upper latch-monitor switch circuit is blown when the door is opened, check the

upper latch switch and monitor switch according to the Test Procedure for those switches, before

replacing the blown fuse.

If the fuse is replaced, the monitor switch should be replaced at the same time.

If the fuse is blown by improper switch operation, adjust or replace the defective switch, fuse at

the same time.

Replace the fuse and monitor switch, even if the switches operate normally

CAUTION; REPLACEMENT FUSE MUST BE THE LISTED FUSE IN PARTS LIST.

H TEMP. FUSE TEST

A continuity check across the temp. fuse terminals should indicate a closed circuit.

If the temperature of the magnetron reaches 142 ‘C, the temp. fuse opens. If the temp. fuse has

opened, replace the fuse. An open temp. fuse indicates overheating of the magnetron assembly.

Check for restricted air flow to the magnetron through the opening in the chassis, especially the

cooling duct and tolling fan.

I THERMAL CUT-OUT

A continuity check across the thermal cut-out terminals should indicate a closed circuit unless

the temperature of the thermal cut-out reaches approximately 140 “C. The termal cut-out resets

automatically at approximately 115 “C.

If the thermal cut-out has opened under the normal condition, replace the same one is parts list.

An open thermal cut-out indicates overheating of the heater unit. Check for restricted air flow

to the heater unit through the vent holes of the oven cavity, especially the heater duct and con-

vection fan

.

16

R -8580

TEST PROCEDURES (CONT’D) \

PROCEDURE

LETTER COMPONENT TEST

CONVECTION HEATER TEST

Make sure the convection heater is fully cooled and test as follows;

a. Disconnect wire leads and measure the resistance with an ohmmeter. On the R x 1 scale, the

resistance between the convection heater terminals should be approximately 38 ohms.

b. Disconnect wire leads and measure the insulation resistance with 500V - IOOM R insulation

resistance meter.

The insulation resistance between convection heater terminal and cavity should be more than

0.5M R.

K THERMISTOR TEST

Disconnect connector-E from the control unit. Measure the resistance of the thermistor with an

ohmmeter. Connect the ohmmeter leads to Pin No’s E-3 and E-4.

Room Temp. Resistance

20 “C - 30 “C Approx. 350 n - 155 S2

If the meter does not indicate above resistance, replace the thermistor.

L DAMPER MOTOR TEST

When the power cord is plugged into the wall receptacle, and 240 volts A.C. is supplied to the

damper motor the motor operates until the damper is opened and the damper switch closes. Then

the damper motor stops operation.

If the damper motor does not operate, check for input voltage by A.C. volt-meter at the motor.

1. Disconnect the power cord from the wall receptacle.

2. Disconnect the wire leads of motor and connect the meter leads to the wire leads of main wire

harness.

3. Reconnect the power cord into the wall receptacle.

If 240 volts A.C. is indicated at the wire leads, replace the motor.

Not indicated, check the wire harness and the relay unit. (RD82EOl U)

M DAMPER SWITCH TEST

Disconnect the wire leads from the switch terminals and connect ohmmeter leads to the common

(COM) and normally open (NO) terminals of the switch.

1. When switch actuator is pushed by the damper motor cam, the meter should indicate a closed

circuit.

2. When the power cord is plugged into the wall receptacle, the damper motor operates and

damper cam starts to rotate.

The switch actuator is released the meter should indicate an open circuit.

If improper operation is indicated, replace the damper switch. (RD82702U)

17

R-8580

TEST PROCEDURES (CONT’O)

PROCEDURE

LETTER COMPONENT TEST

N RELAY UNIT TEST

The relay unit consists of circuits including the shut-off relays, buzzer, transformer, etc.

Plug power cord into wall receptacle “88:88” will be flashing in the display.

Remove the outer case and check voltage between Pin Nos. 1 and 3 of the 6-pin connector (A)

on the relay unit with an A.C. voltmeter.

The meter should indicate 240 volts, if not check oven circuit.

Shut-off, Cook and Heater Relay Test

These relays are operated by D.C. voltage.

Check voltage at the relay coil with a D.C. voltmeter during the microwave or convection cooking

operation.

DC. voltage indicated .,........ Defective relay.

DC. voltage not indicated . . . . . . ..Check diode which is connected to the relay coil. If diode is

good, control unit is defective.

I RELAY SYMBOL I OPERATIONAL CONNECTED COMPONENTS

VOLTAGE I

RYl (COOK) Approx. 14 V. D. C.

RY2 Approx. 14 V.D.C.

RY3 Approx. 14 V.D.C.

RY4 (HEATER) Approx. 14 V.D.C.

RY5 Approx. 14 V. D. C.

RY6 Aoorox. 14 V.D.C.

Power transformer

Oven lamp/Turntable motor

Convection motor

Heating element

Cooling fan motor

DamDer motor

(RD82R02U)

18

TEST PROCEDURES (CONT’O)

PROCEDURE

LETTER COMPONENT TEST

TOUCH CONTROL PANEL ASSEMBLY TEST

The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc.

Therefore, unlike conventional microwave ovens, proper maintenance cannot be performed with

only a voltmeter and ohmmeter. In this service manual, the touch control panel assembly is di-

vided into three units Control Unit, Key Unit and Relay Unit and troubleshooting by unit re-

placement is described according to the symptoms indicated.

1. Key Unit.

The following symptoms indicate a defective key unit. Replace the key unit.

a) When touching the pads, a certain pad produces no signal dt all.

b) When touching a number pad, two figures or more are displayed.

c) When touching the pads, sometimes a pad produces no signal.

2. Control Unit

The following symptoms indicate a defective control unit. Replace the control unit.

2-1 In connection with pads.

a) When touching the pads;a certain group of pads do not produce a signal.

b) When touching the pads, no pads produce a signal.

2-2 In connection with indicators

a) At a certain digit, all or some segments do not light up.

b) At a certain digit, brightness is low.

c) Only one indicator does not light up.

d) The corresponding segments of all digits do not light up; or they continue to light up.

e) Wrong figure appears.

f) A certain group of indicators do not light up.

g) The figure of all digits flicker.

2-3 Other possible troubles caused by defective control unit.

a) Buzzer does not sound or continues to sound.

b) Clock does not operate properly.

c) Cooking is not possible.

d) Proper temperature measurement is not obtained.

Note: When defective components, the Control Unit, Key Unit or Relay Unit are replaced, the

defective part or parts must be properly packed for return in the shipping carton, with its

cushion material, in which the new replacement part was shipped to you. (RD82SOl U)

P KEY UNIT TEST

If the indicator does not respond to touching a key Pad use the following matrix and place a

jumper wire between the proper pin connections making momentary contact with the cable

connector disconnected from the control unit.

If the indicator responds and oven goes into operation, the key unit was faulty.

If there is no response, replace the control unit,

-9

5-l 3 160°C 4 150°C 3 13o”c 2 70°C 1

I I I I 40% I

0 250°C 9 230-C 8 220°C 7 200% 6 180% LowM’

HIGH MED HIGH MED MU) Low LOW F

CLOCK 1 CLEAR 1 COOK 1 HOU) DI

I 1 KEY UNIT ‘]

19

TEST PROCEDURES (CONT’O)

PROCEDURE

LETTER COMPONENT TEST

0 AH SENSOR TEST

Checking the initial sensor cooking condition

(1) The oven should be plugged in at least five minutes befor sensor cooking.

(2) Room temperature should not exceed 35 “C.

(3) The unit should not be installed in any area where heart and steam are generated. The

unit should not be installed, for example, next to a conventional surface unit. Refer to the

“INSTALLATION Instruction”.

(4) Exhaust vents are providend on the back of the unit for proper cooling and air flow in the

cavity.To permit adequate ventilation, be sure to install so as not to block these vents,

There should besome space for air circulation.

(5) Be sure the exterior of the cooking container and the interior of the oven are dry. Wipe

off any moisture with a dry cloth or paper towel.

(6) The Sensor works with food at normal storage temperature.For example, chicken pieces

would be at refrigerator temperature and canned soup at room temperature.

(7) Avoid using aerosol sprays or cleaning solvents near the oven while using Sensor set-

tings. The sensor will detect the vapor given of by the spray and turn off befor food is

properly cooked.

(8) After 30 minutes if the sensor has not detected the vapor of the food, ERROR will appear

and the oven will shut off.

Water load cooking test

Make sure the oven has been plugged in at least five minutes before checking sensor cook op-

eration The cabinet should be installed and screws tightened.

(1) Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup.

(2) Place the container on the center of tray in the oven cavity.

(3) Close the door.

(4) Touch SENSOR COOK pad and number pad I. Now, the oven is in the sensor cooking

condition and SC-l will appear in the display.

(5) Touch Start pad.The oven will operate for the first 16 seconds, without generating micro-

wave energy.

When the AH sensor is defective (open or short), ERROR will appear in the display after 16

seconds cooling time.

If ERROR appears check sensor wire connections and/or AH sensor.

NOTE: ERROR will appear if the door is opend or STOP/CLEAR pad is touched during first

stage of sensor cooking.

(6) After approximately 16 seconds, microwave energy is produced, oven should turn off when

water is boiling (bubling).

If the oven does not turn off, replace the AH sensor or check the control unit, refer to expla-

nation below:

TESTING METHOD FOR AH SENSOR AND/OR CONTROL UNIT

To determine if the sensor is defective, the simplest method is to replace it with a new re-

placement sensor.

(1) Disconnect oven from power supply and remove outer case.

(2) Discharge the high voltage capacitor.

(3) Remove the AH sensor.

(4) Install the new AH sensor.

(5) Re-install the outer case.

(6) Reconnect the oven to the power supply andcheck the sensor cook operation proceed as

follows:

6-1. Touch SENSOR COOK pad and number 0 pad.

6-2. Touch Start pad. The control panel is in automatic Sensor operation.

6-3. The oven will turn off automatically when the water is boiling (bubling).

If new sensor dose not operate properly, the problem is with the control unit.

20

R-8580

TEST PROCEDURES (CONT’D)

PROCEDURE

LETTER COMPONENT TEST

CHECKING CONTROL UNIT

(1) Disconnect oven from power supply and remove outer case.

(2) Discharge the high voltage capacitor.

(3) Disconnect the wire leads from the cook relay.

(4) Disconnect the sensor connector that is mounted to lower position of control panel.

(5) Then connect the dummy resistor circuit (see fig.) to the sensor connector of control panel.

(6) Reconnect the oven to the power supply and check the sensor cook operation proceed as

follows:

6-1. Touch SENSOR COOK pad and number 0 pad.

6-2. The control panel is in the sensor cooking operation.

6-3. After approximately 20 seconds, push plunger of select switch.

This condition is same as judgement by AH sensor.

6-4. After approximately 3 seconds, cooking operation turns off, an audible signal will

sound, and the display will then revert to the time of day.

If the above is not the case, the control unit is probably defective.

If the above is proper, the AH sensor is probably defective. Plunger

0-J

To Connector (F)

on Control Untt

CONNECTOR

NC

NO

Rl, R2 : loon t 1% 1/2w

R3 : 10kR ? 5% 1/4W

R4 : 12kR * 5% 1/4W

F-l -

F-2..--

F-3 rc- I Switch

R2 R4 iNO. -2

Sensor Dummy Resistor Circuit

R PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING

BOARD(PWB) IS OPEN.

To protect the electronic circuits, this model is provided with a fine foil pattern added to the

primary on the PWB, and this fine pattern service as a substitute coil. If the foil pattern is open,

follow the troubleshooting guide given below for repair.

_ .--

Problem: POWER C

JN, indicator does not light up.

STEPS OCCURANCE CAUSE OR CORRECTION

1 The rated voltage is not applied to POWER terminal Check supply voltage and oven main unit.

of CPU connector (CN-A)

2 The rated voltage is applied to primarv side of Dower Power transformer or secondarv circuit defective.

NOTE:* At the time of these repairs, make visual in-

spection of the varistor for burning damage

and examine the transformer with tester for the

presence of layer short-circuit (check primary

coil resistance).

If any abnormal condition is detected, replace

the defective parts.

21

R-8580

TOUCH CONTROL PANEL ASSEMBLY

OUTLINE OF TOUCH CONTROL PANEL

The touch control section consists of the following

units as shown in the touch control panel circuit.

(1) Relay Unit

(2) Key Unit

(3) Control Unit

The principal functions of these units and the signals

communicated among them are explained below.

(RD911 A4U)

Relay Unit

Relay unit consists of six relays (RYI -RY6), power

source circuit and buzzer circuit. (RD914BlU)

Key Unit

The key unit is composed of a matrix, signals generated

in the LSI are sent to the key unit through E7,E8,

El 1 -El 3and El 5-E17.

When a key pad is touched, a signal is completed

through the key unit and passed back to the LSI

through AN4-AN7 to perform the function that was

requested. (RD913Al U)

Control Unit

Control unit consists of LSI, power source circuit,

synchronizing signal circuit, ACL circuit, buzzer circuit,

temperature measurement circuit, absolute humidity

sensor circuit and indicator circuit. (RD915Bl U)

LSI

This LSI controls the temperature measurement

signal, AH sensor signal, key strobe signal, relay

driving signal for oven function and indicator sig-

nal. (RD916Al U)

Power Source Circuit

This circuit generates voltages necessary in the

control unit.

Symbol Voltage Application

VC -5v LSI (ICI ), ACL circuit and tem-

perature measurement circuit

it -16V Buzzzer circuit and IC2

+0.5v IC2

VP -34v Fluorescent display tube : Grid

and anode voltage

VFI -25V Filament of fluorescent display

tube

VF2 -28V VFI - VF2 voltage

(RD917Al U)

3)

Synchronizing Signal Circuit

The power source synchronizing signal is available

in order to compose a basic standard time in the

clock circuit.

It accompanies a very small error because it works

on commercial frequency.

4)

ACL Circuit

A circuit to generate a signal which resets the LSI

to the initial state when power is supplied.

5) Buzzer Circuit

The buzzer is responsive to signals from the LSI

to emit noticing sounds (key touch sound and

completion sound).

6)

(RD91 AA1 U)

Temperature Measurement Circuit: Oven

temp.

The temperature in the oven cavity is sensed by the

thermistor.

The variation of resistance according to sensed

temperature is detected by the temperature meas-

urement circuit and the result applied to LSI.

The result of detecting is given to LSI controlling

the relay and display.

7) Absolute Humidity Sensor Circuit

The circuit detects absolute humidity of a food

which is under cooking, to allow its automatic

cooking.

8) Door Sensing Switch

A switch to “tell” the LSI if the door is open or

closed.

9)

Relay Circuit

To drive the magnetron, heating element, fan mo-

tor, convection motor,damper motor, turntable

(RD918Al U)

(RD919Al U)

(RD91 FBI U)

(RD91 GA1 U)

(RD91 BAZU)

motor and light the oven lamp. (RD91 CBI U)

10) Indicator Circuit

Indicator element is a Fluorescent Display.

Basically, a Fluorescent Display is triode having a

cathode, a grid and an anode. Usually, the cathode

of a Fluorescent Display is directly heated and the

filament serves as cathode.

The Fluorescent Display 7-digits, 15-segments are

used for displaying figures. (RD91 DA1 U)

22

DESCRIPTION OF LSJ

LSI( IZA096DR)

The I/O signal of the LSI(IZA096DR) is detailed in the following table. (RD93101 U)

PIN NO.

I

l-6 1 SIGNAL ) EO-E5 I I/O / OUT

Digit selection signal.

Refer to the touch control panel circuit about the relation between signals and digits.

Normally, one pulse is output in every synchronized signal period, and input to the grid of the fluorescent disrla[.

(RDS f3Al )

PIN NO. 7 1 SIGNAL j E6 I I/O j OUT

Segment data signals.

Refer to the touch control panel circuit for the relationship between signals and indicators,

Normally, one pulse is output in every synchronized signal period, and input to the anode of the fluorescent dis..lax.

PIN NO. / 8

(RDS SAl )

1 SIGNAL / E7 I I/O j OUT

Segment data siqnal.

Signal similar to E6.

Key strobe signal.

Signal applied to touch-key section.

A pulse signaLis input to AN4-AN7 terminal while one of G-l line keys on key matrix is touched.

(RD939A3U)

PIN NO. j 9 1 SIGNAL j E8 I l/O

Segment data sianal.

j OUT

Signal similar to E6.

Key strobe signal.

Signal applied to touch-key section.

A pulse signal is input to AN4-AN7 terminal while one of G-2 line keys on key matrix is touched.

PIN NO. / IO,11

Segment data sianal.

Signal similar to E6.

1 SIGNAL ! E9,ElO I I/O / OUT

(RD939A3U)

PIN NO. j 12 1 SIGNAL / El 1 I I/O

Segment data signal.

1 OUT

Signal similar to E6.

Key strobe sianal.

Signal applied to touch-key section.

A pulse signal is input to AN4-AN7 terminal while one of G-3 line keys on key matrix is touched.

PINNO. j 13 1 SIGNAL ( El2 I/O

Segment data siganal. I 1 OUT

Signal similar to E6. -s

Kev strobe signal.

Signal applied to touch-key section.

A pulse signal is input to AN4-AN7 terminal while one of G-4 line keys on key matrix is touched.

PIN NO. 14 1 SIGNAL j El3 I l/O

Seament data signal.

) OUT

Signal similar to E6.

Kev strobe signal.

Signal applied to touch-key section.

A pulse signal is input to AN4-AN7 terminal while one of G-5 line keys on key matrix is touched.

(RD939AZU)

(RD939A3U)

23

R-8580

PIN NO. 15 1 SIGNAL / El4 I I/O j OUT

Segment data signal.

Signal similar to E6.

PIN NO. / 16 1 SIGNAL j El5 I I/O 1 OUT

Seqment data siqnal.

Signal similar to E6.

Kev strobe siqnal.

Signal applied to touch-key section.

A pulse signal is input to AN4-AN7 terminal while one of G-6 line keys on key matrix is touched.

(RD939A2U)

(RD939A3U)

PINNO. I17 1 SIGNAL 1 El 6 I I/O ) OUT

Segment data siqnal.

Signal similar to E6.

Kev strobe siqnal. --

Signal applied to touch-key section.

A pulse signal is input to AN4-AN7 terminal while one of G-7 line keys on key matrix is touched.

PIN NO. / 18 1 SIGNAL 1 El7 I I/O 1 OUT

Seqment data siqnal.

Signal similar to E6.

Kev strobe siqnal.

Signal applied to touch-key section.

A pulse signal is input to AN4-AN7 terminal while one of G-8 line keys on key matrix is touched.

(RD939A3U)

PIN NO. 1 19,20

Seqment data signal.

Signal similar to E6.

1 SIGNAL j El 8,E19 I I/O j OUT

(RD939A2U)

PIN NO. / 21-24 1 SIGNAL 1 E20-E23 I I/O ; OUT

Used for initial balancing of the bridge circuit(absolute himidity sensor). (RD936Al U)

PIN NO. ) 25 1 SIGNAL j EX I l/O IN

Internal clock oscillation frequency input settinq.

The internal clock frequency is set by inserting the ceramic filter oscillation circuit with respect to X terminal.

PIN NO. j 26 1 SIGNAL j X

Internal clock oscillation frequency control output.

Output to control oscillation input of EX.

PIN NO. j 27

Auto clear terminal.

(RD93EA2U)

I I/O / OUT

(RD93EAl U)

1 SIGNAL / RESET I I/O 1 IN

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

Temporarily set to “L” level the moment power is supplied, at this time the LSI is reset,

Thereafter set at “H” level. (RD93MA2U)

PIN NO. 1 28 1 SIGNAL / SO E24 I I/O / OUT

Segment data siqnal.

Signal similar to E6. (RD939A2U)

24

R -8580

PIN NO. 1 29 1 SIGNAL j SI E25 I I/O / OUT

Used for initial balancing of the bridge circuit(absolute himidity sensor). (RD936Al U)

PIN NO. / 30 1 SIGNAL / E26 I I/O / OUT

Signal to sound buzzer.

A: Key touch sound.(O.l sec.)

B: Completion sound.(2.0 sec.)

C: When the temperature of the oven cavity reaches the preset temperature in the preheating mode, or when the

preheating hold time (15 minutes) is elapsed.

(I .O sec. ON-l .O sec. OFF repeat) (RD93LA2U)

PIN NO. 1 31 SIGNAL j IRQ E27 I l/O / IN

Signal svnchronized with commercial source frequencv(50Hz).

This is the basic timing for time processing of LSI. (RD93FEl U)

PIN NO. 32 SIGNAL vss I I/O IN

Power source voltage: -5V.

VC voltage of power source circuit input. (RD93GAl U)

PIN NO. j 33 1 SIGNAL / RO I I/O j OUT

Magnetron high-voltaae circuit driving signal.

To turn on and off the cook relay.

In HIGH operation, the signals holds “L” level during microwave cooking and “H” level while not cooking. In other

cooking modes (MED. HIGH, MED., MED. LOW, LOW) the signal turns to “H” level and “1” level in repetition

according to the power level. (RD933A2U)

PIN NO. 1 34 1 SiGNAL ( RI I I/O j OUT

Oven lamp and turntable motor driving siqnal.(Square Waveform:fiOHz)

To turn on and off the control relay.

The pulse signal(50Hz) is delivered to the control relay driving circuit and cook relay, heater relay control circuit.

(RD932Fl U)

PIN NO. 35 SIGNAL / R2 I l/O j OUT

Heating element driving signal.

To turn on and off the heater relay.

“1” level during convection cooking; “H” level otherwise.

During convection cooking or mix cooking, the signal becomes “H” level when the temperature of the oven cavity

exceeds the predetermined temperature. (RD93464U)

PIN NO. j 36 1 SIGNAL / R3 I I/O j OUT

Coolinrr fan motor driving signal.

To turn on and off the cooling fan motor relay, “1” level during both microwave and convection cooking; “H” level

otherwise. fRD934B2Ul

PIN NO. 1 37 1 SIGNAL j R4 I I/O j OUT

Convection motor driving sianal.

To turn on and off the convection motor. “1” level during CONVECTION or MIX COOK; “H” level otherwise.

(RD93468U)

25

R -8580

PIN .NO. / 38 1 SIGNAL / R5

Damper motor relav driving signal.

To turn on and off the damper motor relay.

I I/O j OUT

(RD93466UI

PIN NO. 1 39 1 SIGNAL / R6 I l/O 1 OUT

Digit selection signal.

Signal similar to EO.

PIN NO. j 40 1 SIGNAL 1 R7 I I/O / IN

Input signal which communicates the damper open/close information to LSI.

Damper opened; “H” level signal.

(RD938A2U)

Damper closed; “1” level signal. (RD937Bl U)

PIN NO. 1 41 1 SIGNAL 1 E37 1 . I/O 1 IN

Terminal to change functions acccirdinq to the model.

Signal in accordance with the model in operation is applied to set up its function. (Rd93JAl U)

PIN NO. 1 42 1 SIGNAL / E36 I I/O / IN

Input signal which communicates the door open/close information to LSI.

Door closed; “H” level signal.

Door opened; “1” level signal. (RD937Al U)

PIN NO. / 43 1 SIGNAL j AVss I I/O j IN

Connected to VC. (RD93KA3U)

PIN NO. / 44 1 SIGNAL j AVR- I l/O / IN

Reference voltage input terminal.

A reference voltage applied to the A/D converter in the LSI.

The reference voltage is generally maintained at -5V. (RD93GA4U)

PIN NO. 45 1 SIGNAL j AVR+ I l/O 1 IN

Reference voltage input terminal.

A reference voltage applied to the A/D converter in the LSI.

Connectd to GND. (RD93GAW)

PIN NO. ) 46

Connected to GND.

1 SIGNAL AVcc I I/O 1 IN

(RD93KAl U)

PIN NO. / 47 1 SIGNAL 1 AN7 I I/O / IN

Signal cominq from touch kev.

When either one of G-l 2 line keys on key matrix is touched, a corresponding signal out of E7,E8,Ell -El3 and

El 5-El7 will be input into AN7.

When no key is touched, the signal is held at “1” level. (RD93CAl UI

PIN NO. 48 SIGNAL 1 AN6 I l/O IN

Signal coming from touch key.

When either one of G-l 1 line keys on key matrix is touched, a corresponding signal will be input into AN6.

(RD93CA2U)

PIN NO. / 49 1 SIGNAL j AN5 I l/O IN

Signal coming from touch key.

When either one of G-l 0 line keys on key matrix is touched, a corresponding signal will be input into AN5.

(RD93CA2U)

PIN NO. / 50 1 SIGNAL / AN4 I l/O IN

Signal coming from touch key.

When either one of G-9 line keys on key matrix is touched, a corresponding signal will be input into AN4.

(RD93CA2U)

26

PIN NO. / 51 1 SIGNAL / AN3 I I/O / IN

Used for initial balancing of the bridge circuit (absolute humidity sensor).

This input is an analog input terminal from the AH sensor circuit,and connected to the A/D converter built into the

(RD936A3U)

PIN NO. ( 52 SIGNAL / AN2 I I/O IN

AH sensor inuut.

This input is an analog input terminal from the AH sensor circuit, and connected to the A/D converter built into the

LSI. (RD936A2U)

PIN NO. 1 53 1 SIGNAL j AN1 I I/O j IN

Temperature measurement input: OVEN THERMISTOR.

By inputting DC voltage corresponding to the temperature detected by the thermistor, this input is converted into

temperature by the A/D converter built into the LSI. (RD935Al U)

PIN NO. 1 54 1 SIGNAL j AN0 I I/O j IN

Terminal not used.

PIN NO. 1 55

Terminal not used.

(RD93KA2U)

1 SIGNAL j R8 I I/O / OUT

(RD93KA2U)

PIN NO. 1 56-60 ) SIGNAL / R9-RI3 I l/O 1 IN

Terminal not used. (RD93KA2U)

PIN NO. ) 61 SIGNAL j RI4 I I/O 1 IN

Terminal not used. Connected to GND. (RD93KAW)

PIN NO. 1 62 1 SIGNAL j RI5 1 l/O j IN

Terminal for manufacture test.

Normally terminal not used. (RD93lA3U)

PIN NO. 63

Terminal not used.

PIN NO. j 64

Connected to GND.

1 SIGNAL 1 NC I I/O / NC

(RD93KA2U)

1 SIGNAL ) vcc I l/O j IN

(RD93KAl U)

27

R-8580

ABSOLUTE HUMIDITY SENSOR CIRCUIT

(1) Structure of Absolute Humidity Sensor

The absolute humidity sensor includes two

thermistors as shown in the illustration. One

thermister is housed in the closed vessel filled with

dry air while another in the open vessel. Each

sensor is provided with the protective cover made

of metal mesh to be protected from the external

airflow.

Internal Structure of Sensor

(2) Operational Principle of Absolute Humidity

Sensor

The figure below shows the basic structure of an

absolute humidity sensor. A bridge circuit is

formed by two thermistors and two resistors (Rl

and R2).

The output of the bridge circuit is to be amplified

by the operational amplifier.

Each thermister is supplied with a current to keep

it heated at about 150 “C (302 “F) and the resultant

heat is dissipated in the air and if the two

thermistors are placed in different humidity condi-

tions they show different degrees of heat

conductivity leading to potentiaJ difference be-

tween them causing an output voltage from the

bridge circuit, the intensity of which is increased

as the absolute humidity of the air increases. Since

the output is very minute, it will be amplified by the

operational amplifier.

C Operational

RI amplifier

T output

I vottaga

GIP-

- .

sit : RI -

S: Thhenms

R3 C: Thermistor

closed vessl

IDetector Circuite of

Sensor Circuit

t Absolute humidity vs.

output voltage characteristic

H

=

e

5

0.

2

\JJj\i

1 b

Absolute humidity (g/m’ 1

Absolute Humidity

This detector circuit is used to detect the output

voltage of the absolute humidity circuit to allow the

LSI to control sensor cooking of the unit.

When the unit is set in the sensor cooking mode,

16 seconds later the detector circuit starts to func-

tion and the LSI observes the initial voltage

availabel at its AN2 terminal. With this voltage

given, the switches SW1 to SW5 in the LSI are

turned on in such a way as to change the resistance

values in parallel with R50.

-1. Changing the resistance values results in that

there is the same potential at both F-3 terminal of

the absolute humidity sensor and AN3 terminal of

the LSI. The voltage of AN2 terminal will indicate

about -2.5V. This initial balancing is set up about

16 seconds after the unit is put in the Sensor

Cooking mode.

As sensor cooking proceeds, the food is heated to

generate moisture by which the resistance balance

of the bridge circuit to deviate increasing the volt-

age available at AN2 terminal of the LSl. Then the

LSI observes that voltage at AN2 terminal and

compares it with its initial value, and when the

comparison rate reaches the preset value (fixed for

each menu to be cooked), the LSI causes the unit

to stop sensor cooking; thereafter, the unit goes

into the next necessary operation automatically.

When the LSI starts to detect the initial voltage at

AN2 terminal 16 seconds after the unit has been

put in the Sensor Cooking mode, if it is im possible

to take a balance of the bridge circuit due to dis-

connection of the absolute humidity sensor, ER-

ROR will reappear on the display and the cooking

is stopped. (RD72001 U)

1 )Absolute humidity sensor circuit

Q!3l

RSO R.watOr Block swt

-.,mJ

! *.*

I, RsO-4)6 24 E23d “’

0 RSO-III7 23 SW301

E22^I

RSO& 22 SW47

0 ” EZl/

c Thcrmlrtor m RSO-7& 2l WC-J

closed vessel ,C c.

I

_ ma--I 7

S Thcrmlrtor In

open vessel

2)lnternal equivalent circuit of 12

Top View

28

R -8580

SERVICING

1. Precautions for Handing Electronic

Components

This unit uses PMOS LSl in the integral part of the

circuits. When handing these parts, the following

precautions should be strictly followed.

PMOS LSI have extremely high impedance at its

input and output terminals. For this reason, it is

easily influenced by the surrounding high voltage

power source, static electricity charged in clothes,

etc,and sometimes it is not fully protected by the

built-in protection circuit.

:;

2)

,

order to protect PMOS LSI.

When storing and transporting, thoroughly

wrap them in aluminum foil.

Also wrap PW boards containing them in

aluminium foil.

When soldering, ground the technician as

shown in the figure and use grounded

soldering iron and work table.

. . appror.lMSl

k /

2. Shapes of Electronic Components AT

Transistor Transistor Transistor

2SB793 2SA937 DTA143ES 1 16 (R112)

DTD143A DTA114YS Resistor Block.

DTC114ES R50, R90, R 110

R112

3. Servicing of Touch Control Panel

We describe the procedures to permit servicing the

touch control panel of the microwave oven and the

cautions you must consider when doing so.

To carry the servicing, power supply to the touch

control panel is available either from the power line

of the oven proper itself of from an external power

source.

(I ) Servicing the touch control panel with

power supply from the oven proper:

CAUTION:

THE HIGH VOLTAGE TRANSFORMER OF

THE MICROWAVE OVEN IS STILL ALIVE

TO GIVE YOU DANGER DURING SER-

VICING.

Therefore, when checking the performance of

the touch control panel,put the outer cabinet

on the oven proper to keep from touching the

high voltage transformer, or unplug the primary

terminal (connector) of the high voltage trans-

former to turn it off; and the end of such con-

nector shall be insulated with an insulating

tape. After servicing, be sure to replace the

leads to their original locations.

A. On some models, the power supply cord be-

tween the touch control panel and the oven

proper is so short that they can’t be separated

from each other.

For those models, therefore, check and repair

all the controls (with the sensor-related ones

included) of the touch control panel while

keeping it in contact with the oven proper.

B. On some models, on the other hand, the power

supply cord between the touch control panel

and the oven proper is so long that they may

be separated from each other. For those mod-

els, therefore, it is allowed to check and repair

the controls of the touch control panel while

keeping it apart from the oven proper;in this

case you must short both ends of the door

sensing switch (on PWB) of the touch control

panel with a jumper, which brings about an

operational state that is equivalent to that with

the oven door being closed.

As to the sensor-related controls of the touch

control panel, their checking is allowed if the

dummy resistor(s) whose resistance is equal to

that of those controls is used.

(2) Servicing the touch control panel with

power supply from an external power

source:

Disconnect the touch control panel completely

from the oven proper,and short both ends of

the door sensing switch (on PWB) of the touch

control panel,which brings about an opera-

tional state that is equivalent with the oven

door being closed. And connect an external

power source to the power input terminal of the

touch control panel, and then it is allowed to

check and repair the controls of the touch

control panel;as in the case of (1 )-B above, it

is here also possible to check the sensor-related

controls of the touch control panel by using the

dummy resistor(s).

4. Servicing Tools

Tools required when servicing the touch control

panel assembly.

1) Soldering iron: 30W

(To prevent leaking current, it is recommended to

use a soldering iron with a grounding terminal.)

2) Oscilloscope: Single beam, frequency range:

DC - IOMHz type or more ad-

vanced model.

3) Others: Hand tools

5. Other Precautions

1)

2)

3)

4)

5)

Before turning on the power source of the

control unit, remove the aluminum foil applied

for preventing static electricity.

Connect the connectors of the indicator and

key units to the control unit taking care that the

lead wires are not twisted.

After aluminum foil is removed, take extra care

that abnormal voltage due to static electricity

etc. is not applied to the input or output termi-

nals.

Attach connectors, electrolytic capacitors, etc.

to PWB, taking care that all connections are

tight.

Be sure to use specified components where

high precision is required. (RD94ZAZU)

29

R -8580

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

WARNING: To avoid possible exposure to microwave 4. There is any defective parts in the interlock,

A.

B.

1.

2.

3.

4.

5.

energy;

Before operating the oven oven door or microwave generating and trans-

mission assemblv.

1.

2.

Do

the

1.

2.

3.

Make sure that unlatching the door slowly is

accompanied by a click indicating actuation of

the monitor switch and latch switches.

Check visually the door seal for arcing and

damage.

not operate the oven until after repair if any of

following conditions exist;

Door does not close firmly against the front of

appliance.

There iS a broken door hinge or support.

The door is bent or warped. -

5. ------ ---I.

There is any other visible damage to the oven.

C. Do not operate the oven

1. Without the RF gasket.

2. If the door is not closed.

CAUTION: DISCONNECT OVEN FROM POWER

SUPPLY BEFORE REMOVING

OUTER CASE. DISCHARGE HIGH

VOLTAGE CAPACITOR BEFORE

TOUCHING ANY OVEN COMPO-

NENTS OR WIRING. (RDA? 203U)

POWER TRANSFORMER REMOVAL

Disconnect oven from power supply and remove 3.

outer case.

Discharge high voltage capacitor.

Disconnect filament leads of transformer from the

magnetron.

Disconnect wire leads from the transformer.

Remove two (2) screws and one (I) washer hold-

ing the transformer to the cabinet base.

4.

5

Re-install

1.

2.

1.

2.

3.

4.

I.

2.

3.

4.

::

3.

Rest the transformer on the base cabinet with its

primary terminals toward rear cabinet.

Insert the two edges of the transformer into two

metal tabs of the base cabinet.

6.

Make sure the transformer is mounted correctly

to the corners underneath those tabs

After re-installing the transformer, secure the

transformer with two screws to the cabinet base,

one is with outertooth washer and the other is

without outer-tooth washer.

Re-connect the wire leads (primary and high

voltage) to the transformer and filament leads of

transformer to the magnetron, referring to the

“Pictorial Diagram”.

Re-install the outer case and check that the oven

is operating properly.

HIGH VOLTAGE RECTI Ii FIER REMOVAL

outer case.

Disconnect oven from power suppply and remove

Discharge the high voltage capacitor.

Remove one (1) screw holding the rectifier to the

capacitor holder.

Disconnect the rectifier from the capacitor.

RECTIFIER, THE GROUND SIDE

CAUTION: WHEN REPLACING THE SILICON

TERMINAL MUST BE SECURED

FIRMLY WITH A GROUNDING

SCREW.

HIGH VOLTAGE CAPACITOR REMOVAL

Disconnect oven from power supply and remove

outer case.

Discharge the high voltage capacitor.

Disconnect the high voltage wire leads from high

voltage capacitor.

Remove one (1) screw holding capacitor mounting

bracket.

5. Disconnect rectifier and high voltage rectifier from

the capacitor. .br

6. Remove one (1) screw holding the high voltage

rectifier and the capacitor holder.

7. Remove the capacitor from the holder.

TURNTABLE MOTOR AND/OR COUPLING REMOVAL

Disconnect the oven from power supply.

Remove one (I ) screw holding the turntable motor

cover to the base cabinet and take off the turntable

motor cover.

Disconnect 2-pin connector from the turntable mo-

tor.

4.

5

6.

Remove the two (2) screws holding the turntable

motor to the mounting plate of the oven cavity.

Pull the turntable coupling out of the oven cavity.

The turntable motor is now free.

30

1.

2.

3.

4.

5.

6.

8.

9.

MAGNETRON REMOVAL

Disconnect oven from power supply and remove

outer case.

screws, a carefull attention should be necessary to

Discharge the high voltage capacitor. prevent the magnetron fall away.

Disconnect wire leads from the magnetron.

6. Remove the magnetron (with magnetron cooling

Remove the magnetron temp. fuse fitted to duct(B)) from the unit with a careful attention the

waveguide flange. And release the wire leads from magnetron tube should not hit by any metal object

around the tube.

the hole of magnetron cooling duct (B). And re-

lease the AH sensor harness from hole of chassis

support. Remove four (4) screws holding the

chassis support to cooling duct (A), waveguide,

rear cabinet, control back plate.

7. Remove one (1) screw holding cooling duct (B) to

the magnetron.

8. Remove cooling duct (B) from the magnetron.

9. Now the magnetron is free.

CAUTION:

Release the tab on cooling duct (B) to hold cooling

duct (A).

Carefully remove four (4) mounting screws holding

the magnetron to waveguide, when remove the

WHEN REPLACING THE MAGNETRON,

BE SURE THE R.F. GASKET IS IN

PLACE AND THE MAGNETRON

MOUNTING SCREWS ARE TIGHTENED

SECURELY.

CONVECTION MOTOR REMOVAL

Disconnect oven from power supply and remove

outer case.

Disharge the high voltage capacitor.

Remove sliding the thermal cut-out with its wire

lead on.

Disconnect wire leads from the convection motor

and convection heater.

Disconnect the 2-pin connector from thermistor.

Remove eleven (11) screws holding the heater duct

to the oven cavity.

Remove two (2) screws holding the heater duct to

thermal protection plate (bottom).

The heater unit is now free.

Remove the four (4) screws holding the thermal

protection plate(left) to the heater duct.

1 O.The thermal protection plate(left) and sheet( left)

are now free.

11 .Remove three (3) screws holding the convection

motor mounting plate to the heater duct.

12.Pull the convection motor shaft out of convection

fan.

13.Now the convection motor with the motor mount-

ing plate is free.

1.

2.

3.

4.

5.

14.Remove two (2) nuts holding the motor mounting

plate to the convection motor.

15.Convection motor is now free.

Re-install

1. Re-install the convection motor mounting plate to

the convection motor by the two (2) nuts.

2. Put the convection fan to the motor shaft.(fit with a

E-ring.)

3. Re-install the heater duct to the convection motor

mounting plate by the three (3) screws.

4. Make sure the rotation of the convection motor.

5. Re-install the thermal protection plate to cover the

heatewr duct with sandwiching the thermal pro-

tection sheet.

6. Re-install the heater unit to the left side of the oven

cavity by the eleven (11) screws. Re-install the

heater unit to thermal protection plate (buttom) by

two (2) screws.

7. Re-install the wire leads to the convection motor,

convection heater, thermister connector.

Refering to “Pictorial diagram”.

8. Re-install the thermal cut-out.

COOLING FAN MOTOR REMOVAL

Disconnect oven from power supply and remove

outer case.

Discbarge the high voltage capacitor.

Disconnect wire leads from the cooling fan motor.

Release AH sensor harness from chassis support

and cooling duct (A).

Remove four (4) screws holding the chassis sup-

port to rear cabinet, cooling duct

flange and control panel back plate.

(A), waveguide

6. Release the tab on cooling duct (B) holding cooling

duct (A). -

7. Remove duct (A) with the cooling fan motor from

the unit.

The cooling fan motor assembly is now free.

8. Remove the fan blade from the cooling fan motor

shaft by pulling out the fan retainer clip.

9. Remove two (2) screws and nuts holding cooling

fan motor to the cooling duct (A).

The cooling fan motor is now free.

31

R -8580

DAMPER ASSEMBlY REMOVAL

1. Disconnect oven from power supply and remove 7. Raise the stopper of the damper shaft, and pull out

outer case. the damper shaft.

2. Discharge the high voltage capacitor.

3. Disconnect wire leads from damper motor and

damper switch.

8. Pull the damper ass’y out of the thermal protection

plate( right).

4. Do above the MAGNETRON REMOVAL from No.3

to No.6.

9. Remove one (1) screw holding the motor to the

damper.

5. Remove one (1) screw holding the magnetron air

guide to waveguide flange.

6. Remove the magnetron air guide.

1 O-The damper is now free.

11 .Remove one (1) screw holding the damper switch

to the damper.

12.Now, the damper switch is free.

CONVECTION HEATER OR CONVECTION FAN REMOVAL

I. Do CONVECTION MOTOR REMOVAL from No.1

to No.10.

2. Remove five (5) screws holding the convection air

guide (4-40,4-41,4-42,4-45) to the heater duct.

3. Remove four (4) screws holding the convection air

guide (4-38) to the heater duct.

4. The convection air guide is now free.

5. Remove two (2) screws holding heating element

holders to the heater duct and remove them.

6. Remove two (2) screws holding convection heater

to heater duct.

7. Pull the convection heater out of the heater duct.

8. Now the convection heater is free.

CONVECTION FAN

1. Do CONVECTION MOTOR REMOVAL from No.1

to No.13.

2. Remove two (2) screws holding the shaft mounting

plate ass’y to the heater duct.

3. Pull the convection fan and washer out of the

heater duct.

4. Convection fan is now free.

UPPER LATCH SWITCH / MONITOR SWITCH REMOVAL

1. Disconnect oven from power supplv and remove Re-install

. . .

outer case.

2. Discharge the high voltage capacitor.

3. Disconnect the wire leads from the switches.

4. Remove the one (1) screw holding the upper latch

hook to the oven flange.

5. Remove the upper latch hook assembly from oven

1. Re-install each interlock switch in its place. The

monitor switch is in the upper position and the up-

per latch switch is in the lower position.

2. Re-connect the wire leads to each switch.

Refer to the pictorial diagram.

3. Secure the upper latch hook (with the one (‘I )

mounting screw) to the oven flange.

flange.

6. Push outward on the two (2) retaining tabs holding

the switch in place.

7. The switch is now free.

4. Make sure that the monitor switch and upper latch

. _

switch are operating properly.

Refer to chapter “Test Procedure” and “Adjustment

procedure”. ( RDA1203tJ)

LOWER LATCH SWITCH AND STOP SWITCH REMOVAL

1. Disconnect the oven from the power supply and

remove the outer case.

2. Discharge the high voltage capacitor.

3. Disconnect the wire leads from the switches.

4. Remove the one (1) screw holding the lower latch

hook to the oven cavity front frange.

5. Remove the lower latch hook from the flange by

moving it downward.

6. To remove the individual switch from the lower

latch hook, push outward the two (2) retaining tabs

holding the switch in place.

7. The switch is now free.

Re-install

1. Re-install each interlock switch in its place. The

stop switch is in the upper position and the lower

latch switch is in the lower position.

2. Re-connect the wire leads to each switch.

Refer to the pictorial diagram.

3. Secure the lower latch hook (with the one (1)

mounting screws) to the oven flange.

4. Make sure that the lower latch switch and stop

switch are operating properly.

Refer to chapter “Test Procedure” and “Adjustment

procedure”. (RDAl203U)

(RDA1203U)

32

CONTROL PANEL ASSEMBLY AND CPU UNIT REMOVAL

The complete control panel should be removed for re-

placement of components except the relay unit.

To remove the control panel, proceed as follows:

1, Disconnect oven from power supply and remove

outer case.

2. Discharge the high voltage capacitor.

3. Disconnect the wire connectors and wire leads from

the relay unit and CPU unit.

4. Disconnect a connector from the CPU unit.

5. Remove one (I ) screw holding the control panel

back plate to the chassis support.

6. Remove the two (2) screws holding the bottom

edge of the back plate to the cabinet base.

7. Remove one (I) screw holding the back plate to the

oven cavity flange.

Replacement of individual component is as follows:

CPU UNIT AND KEY UNIT

I, Disconnect the wire connector of CPU unit from the

relay unit.

2. Remove the four (4) screws holding the panel

frame to the back plate.

3. Separate the panel frame and back plate.

4. Remove the three (3) screws holding the CPU unit

to the panel frame.

5. Lift up the control unit and disconnect the key

connector from the CPU unit.

6. Now, the CPU unit and frame assembly are sepa-

8. Lift up and pull the control panel forward. rated.

UPPER LATCH/LOWER LATCH/STOP SWITCHES

AND MONITOR SWITCH ADJUSTMENT

If the upper latch,lower latch switches stop switch and

monitor switch do not operate properly due to a

mis-adjustment, the following adjustment should be

1. Loosen the one (1) screw holding the upper Jatch

book to the oven cavity front flange and the one (1)

made.

screw holding the lower latch hook to the same

flange.

2. With the door closed, adjust the lower latch book

by moving it back and forth and then adjust the

upper latch hook by moving it back and forth, or

up and down. In and out play of the door allowed

by the upper and lower latch hooks should be less

than 0.5 mm. The vertical position of the upper

latch hook should be placed where the upper latch

switch and monitor switch have activated with the

door closed. Vertical adjustment of the lower latch

book is not possible.

3. Secure the screws with washers firmly.

4. Now, make sure of the upper latch switch opera-

tion. If the upper latch switch has not, activated with

the door closed, loose the one (1) screw holding

the upper latch book to the oven cavity front flange

and adjust the upper latch hook position.

After the adjustment, make sure of the following:

1. The in and out play of the door remains less than

0.5 mm at latched position. First check the upper

latch hook position, pushing and pulling the upper

portion of door toward the oven face. Then check

the lower latch hook position, pushing and pulling

the lower portion of door toward the oven face.

Both results (plays of the door) should be less than

0.5mm.

2. The upper latch and lower latch switches interrupt

the circuit before the door can be opened.

4. Re-install the outer case and check for microwave

3. The monitor switch contacts close when the door

leakage around the door with an approved micro-

wave survey meter. (Refer to Microwave Measure-

ment Procedure.)

is opened.

Figure C-l. Latch Switches Adjustment

(RDAl203U)

33

R -8580

DOOR REPLACEMENT AND ADJUSTMENT

DOOR REPLACEMENT

1. Disconnect oven from power supply and remove

outer case.

2. Holding the door, remove three (3) screws securing

the upper door hinge to the oven cavity. The door

assembly is nowfree from the oven cavity.

3. On re-installing new door assembly, secure the door

assembly with the three (3) mounting screws to the

oven cavity.

Make sure the door is parallel with the bottom line

of the oven face plate and the latch heads pass

through the latch holes correctly.

Note: After any service to the door, .-an approved

microwave survey meter should be used to as-

sure compliance with proper microwave

rediation standard.

(Refer to Microwave Measurement Procedure).

Note: If the Latch Heads Need Removal, “TORX T-20”

or “LHXTIX LR-3” Type screwdriver should be

used.

TORX screw

DOOR ASSEMBL

TORX SCREW (T-20)

LATCH HEADS

DOOR ADJUSTMENT

When removing and/or loosening hinges such as in the

case of a door replacement, the following adjustment

criteria are taken. Door is adjusted to meet the fol-

lowing three conditions before tightening the binge

screws.

I. Adjust door latch heads at a position where they

smoothly catch the latch hooks through the latch

holes. Refer to upper latch and lower latch switches

adjustments.

2. Deviation of the door alignment from the horizontal

line of cavity face to be less than 1 mm.

3. Door should be adjusted with its face depressed

toward cavity face.

After hinge screws are tightened under foregoing con-

ditions, recheck 1 and 2.

Note: The door on a microwave oven is designed to

act as an electronic seal preventing the leakage

of microwave energy from the oven cavity during

the cookcycle. This function does not require

that the door be airtight, moisture condensation

tight or light-tigbt. Therefore, the occasional

appearance of moisture, light or the sensing of

gentle air movement around the oven door is not

abnormal and do not of themselves, indicate a

leakage of microwave energy from the oven

cavity. If such were the case, your oven could

not be equipped with a vent, the very purpose

of which is to exhaust the vapor-laden air from

the oven cavity.

OUTER CASE CABINET

OVEN FACE PLATE

Figure C-2. Door Assembly Replacement and Adjustment (RDA1203U)

34

R -8580

MICROWAVE MEASUREMENT

After adjustment of door latch switches, monitor

switch and door are completed individually or collec-

tively, the following leakage test must be performed

with a survey instrument and it must be confirmed that

the result meets the requirements of the performance

standard for microwave oven.

REQUIREMENT

The safety switch must prevent microwave radiation

emission in excess of 5mW/cm2 at any point 5cm or

Sharp Microwave Oven R 8580 Users Manual Unknown

r-8580 to the manual b9c59583-101f-4c47-8afd-56fc57e3c830

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