Sharp R-9200 Service Manual

SHARP SERVICE MANUAL .

S3201 RSZOOJ//

CONVECTION

MICROWAVE OVEN

MODEL

R-9200

In interests of user-safety the oven should be restored to its original

condition and only manufacturer original spare parts must be used.

(RD161OlU)

This is a supplemental Service Manual for Model R-9ZOO. This model is quite similar to Base Model R-9HlO (Refer No. is S9808R9HlOJ//).

Use this supplemental manual together with the Base Model Service Manual. Refer to the Base Model Service Manual for complete operation, service information, etc.

(RD17101U)

TABLE OF CONTENTS

Page

APPEARANCE VIEW

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

Inside front cover

GENERAL IMPORTANT INFORMATION

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

1

CAUTION, MICROWAVE RADlATlON,WARNING

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

1

PRODUCT SPECIFICATIONS

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

2

OPERATION

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

3

FUNCTION OF IMPORTANT COMPONENTS

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

4

SERVICING

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

5

TEST PROCEDURE

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

6

TOUCH CONTROL ASSEMBLY

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

13

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

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

21

MICROWAVE MEASUREMENT

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

22

WIRING DIAGRAM .......................................................................................................................................

23

PICTORIAL DIAGRAM

.................................................................................................................................. 25

CONTROL PANEL CIRCUIT

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

26

PRINTED WIRING DIAGRAM

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

27

PARTS LIST ....................................................................................................................................................

28

SHARP CORPORATION *

Touch Control Panel

-43

1. Ventilation openings

2. Oven lamp

3. Hinges

4. Safety door latches

5. See through door

6. Door open button

7. Touch Control Panel

8. Digital readout

9. Waveguide cover lO.Access cover for oven

lamp replacement

ll.Menue Label for Intelli-

gent Sensor

12.Low rack

13.High rack

14.Defrost rack

Convection I

CONV

AUTO COOK+j

Fan Symbol

Micro/Defrost Symbol

MIX SENSOR DEFROST TEMP

Indicator

WEIGHT ADJUST PAD Press to zero the your own dishes

INTELLIGENT SENSOR PAD Press to select 12 popular Mix, Grill and Micro cooking menu with weight sensor or AH sensor.

cooking with weight sensor.

with weight sensor.

NUMBER AND TEMPERATUREPADS

Press to enter cooking times,

clock time, convection temperature or to select the Intelligent Sensor menus.

POWER LEVEL PADS Press to select microwave

power setting. If not pressed, HIGH is automatically selected.

STOP/CLEAR PAD Press to erase during programming. Press once to stop operation of oven during cooking; press

twice to cancel cooking programme.

AUTO

I

START/CLOCK PAD Press to set clock or Auto Start time.

*SENSOR INSTANT ACTION

PADS Press once to cook 8 popular menus.

CONVECTION COOKIN FUNCTION PADS Press to cook for each tunc-

tion.

*MORE, LESS PADS

Press to increase/decrease the time in one minute increments during cooking or to alter the doneness for the Sensor Instant Action, Intelligent Sensor or Defrost Sensor modes.

IrlNSTANT COOK/START PAD

I

Press once to cook for 1 minute

STOP START INSTANT COOK, -

at HIGH or increase by 1 minute

CLEAR CLOCK START

multiples each time this pad is

\

I I

/ pressed during Microwave,

Convection, Grill or Mix cooking.

SERVICE MANUAL

SHARI=

CONVECTION MICROWAVE OVEN

R-9200

GENERAL IMPORTANT INFORMATION

This Manual has been prepared to provide Sharp Corp.

Service

engineers with Operation and Service Information.

It is recommended that service engineers carefully study the

entire text of this manual and base model manual, so they will

be qualified to render satisfactory customer service.

r-

(RD36106

CAUTION

MICROWAVE RADIATION

Service engineers 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.

(RD36203U)

WARNING

Never operate the oven until the following points are ensured.

(A)The door is tightly closed. (B) The door brackets and hinges are not defective. (C)The door packing is not damaged. (D)The door is not deformed or warped. (E) There is not any other visible damage with the oven.

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

All the parts marked “+‘I on parts list are used at voltages more than 250V.

(RD5111 Ou)

SHARP CORPORATION

OSAKA, JAPAN

R-9ZOO

““?j PRODUCT DESCRIPTION

\ :‘:;j

OPERATING SEQUENCE

- :;--;:;sj

“-” “+$j

FUNCTION OF IMPORTANT COMPONENTS

it< 2 ”

-*: i

-, “, .’ j

I< ” “,

I “s

TEST PROCEDURE

x

*

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” * “> *

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‘f TOUCH CONTROL PANEL

_I

8~ ~9

ASSEMBLY

COMPONENTS REPLACEMENT AND

ADJUSTMENT PROCEDURE

” “*

:<

* -2.

MICROWAVE MEASUREMENT

WIRING DIAGRAM

i

s. ‘.

PARTS LIST

(RD37201 U)

R-9ZOO

PRODUCT DESCRIPTION

SPECIFICATIONS

ITEM

Power Requirements

240 Volts 50 Hertz

DESCRIPTION

Power Consumption

Power Output

Convection Heating element Case Dimensions

Single phase, 3 wire earthed 16OOW (Microwave)

1600W (Convection) 800 watts nominal of RF microwave energy (2 litre water load)

900 watts (I EC-705-1 988) Operating frequency of 2450M Hz 1500 w

Width 627 mm

Height 378 mm Depth 481 mm

Cooking Cavity Dimensions

Width 410 mm

Height 245 mm Depth 410 mm

Control Complement

Touch Control System Clock( I:00 - 12:59 ) Timer (0 - 99 min. 99 sec. )

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

Convection Temperature for Variable Cooking

CONVECTION

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

40 to

250°C Temp. control

LOW

M IX( BAKE) . . . . . . . . . . . . . . . . . . . . . . . .

180°C with 10% microwave power

HIGH MIX( ROAST) m...................

GRILL

200°C with 30% microwave power

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

250°C

INTELLIGENT SENSOR pad

(preheat)

DEFROST SENSOR pad

WEIGHT ADJUST pad

INSTANT ACTION SENSOR pads

NUMBER and TEMPERATURE pads POWER LEVEL pads MORE. LESS pads

STOP/CLEAR pad

Set Weight .

AUTO START/CLOCK pad

1 INSTANT COOK/START pad

Approx. 31 kg

(RD44101 U)

NOTE: Numbers and letters shown after sentences such as “RD44101 U” are for factory use only.

2

--.r-.w-- -.1---- ,---- -._ _ _

R-9ZOO

OPERATING SEQUENCE

INTELLIGENT SENSOR COOKING CONDI-

TION

The oven cooks foods automatically by using the

weight sensor cooking condition or the absolute humidity sensor (AH sensor) cooking condition.

Weight sensor cooking condition.

1. The oven detects the weight of food automatically when food is placed into the oven.

2. The oven sets the cooking condition and cooking time automatically when the food category is inputted.

3. The oven starts cooking when the start button is pressed.

AH sensor cooking condition

1. This is the same as Sensor cooking condition of the base model (R-9HlO)

INSTANT ACTION SENSOR COOKING CONDITION

This is the same as INTELLIGENT SENSOR cooking condition. In this condition the oven starts soon when touching INSTANT ACTION SENSOR pads.

DEFROST SENSOR CONDITION

The oven heats food automatically by using Weight sensor cooking condition.

SENSING FIRE OPERATION

The oven will stop its operation when there is fire in the oven cavity in microwave cooking condition.

l LSI measures the voltage across the temperature

measurement circuit intermittently within a 32 sec-

ond time base since the oven is started in micro-

wave cooking condition.

The oven will stop its

operation when the difference of the voltage is more

than 0.3 volts in microwave cooking condition.

1.

2.

3.

4.

Within a 32 second base, first thermistor is energized for 3 seconds.

After 2 seconds since the

thermistor is energized, the voltage across the tem-

perature measurement circuit is measured. And after 21 seconds since the thermistor is cut off, the convection motor operates for 6 seconds. The oven carries out the procedure above again. If the second voltage is 0.3V higher than the first voltage, LSI judges it is a fire in the oven cavity and stops the oven. When sensor cooking, the sensing fire operation is not carried out until the oven senses the steam from food. Because food cannot be cooked well by rotating the convection fan at that time. After sensing the steam, the sensing fire operation is started. When LSI judges it is fire in the oven cavity, LSI will switch off the relays to the power transformer, fan motor and convection motor and LSI stops counting down. that the fresh air ity.

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CONVECTION , , MOTOR

; I

ON ;I

And then the damper is closed so does not come into the oven cav-

2P

3? ?2 (sec.)

t?Osec. i i ! ’ !

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1 1 3 sec.

I

THERMISTOR

+ ;tc-

I

Sensing Voltage

Sensing the voltage across temperature measurement circuit.

3

WEIGHT SENSOR

FUNCTION OF MAIN COMPONENTS

WEIGHT SENSOR ASSEMBLY

Micr-

computer

Weight Sensor -

Osilator

I

WI)

J-U-L I

-I

1. When the food is placed on the turntable, the gap between the elctrodes increases in direct pro-

portional to the weight of food. The elctrodes have the function of a capacitor.

2. The frequency of

the oscilator changes according to the capacitance of the weight sensor.

3. The micro-computer measures the weight of food by detecting the change in the

oscilating frequency.

R-9ZOO

SERVICING

WARNING TO SERVICE PERSONNEL

Microwave ovens contain circuitry capable of producing very high voltage and current, contact with any part

of the high voltage circuit will result in electrocuition.

REMEMBER TO CHECK 3D

1) Disconnect the supply.

2) Door opened, an.d wedged open.

3) Discharge high voltage capacitor. WARNING AGAINST THE CHARGE OF THE

HIGH-VOLTAGE CAPACITOR

The high-voltage capacitor remains charged about 60 seconds after the oven has been switched off. Wait for 60 seconds and then short-circuit the

connection of the high-voltage capacitor (that is, of the connecting lead of the high-voltage rectifier)

~ against the chassis with the use of an insu-

i lated screwdriver.

Sharp recommend

that

wherever

possible

fault-finding is carried out with the supply discon-

nected. It may in, some cases, be necessary to

connect the supply after the outer case has been

removed, in this event carry out 3D checks and then disconnect the leads to the primary of the power transformer. Ensure that these leads remain isolated from other components and the oven chassis. (Use

insulation tape if necessary.) When the testing is completed carry out 3D checks and reconnect the

leads to the primary of the power transformer.

REMEMBER TO CHECK 4R

1) Reconnect all leads removed from components during testing.

2) Replace the outer case (cabinet).

3) Reconnect the supply.

4) Run the oven. Check all functions.

Microwave ovens should not be run empty. To test for the presence of microwave energy within a cavity, place a cup of cold water on the oven turntable, close the door and set the microwave timer for two (2) minutes. Set the power level to

HIGH and push the START button. When the two minutes has elapsed (timer at zero) carefully check that the water is now hot. If the water remains cold carry out 3IJ checks and re-examine the connections to the component being tested.

When all service work is completed, and the oven is fully assembled, the microwave power output should

be checked and a microwave leakage test carried out.

TROUBLESHOOTING GUIDE

When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks. Many of the possible causes of trouble will

require that a specific test be performed. These tests

are given a procedure letter which will be found in the

“Test Procedure”section.

IMPORTANT: If the oven becomes inoperative be-

cause of a blown fuse M8A in the upper latch switch -

lower latch switch monitor switch - monitor resistor circuit, check the upper latch switch,

lower latch switch, monitor switch and monitor resistor before replacing the fuse M8A.

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POSSIBLE CASE AND ;;l$ETIVE

:ONDITION

I

PROBLEM

Home fuse blows when power supply cord is plugged into wall receptacle.

3FF

Fuse blows when power supply cord is

CONDITION

plugged into wall receptacle.

“88:88” does not appear in display when power cord is first plugged into wall outlet.

Display

does not operate properly when STOP/CLEAR pad is touched. (An audible signal should sound and time of day should appear on display.

Oven lamp does not light with door open. Oven lamp does not light in cook cycle.

(Does light when door is opened.)

ZOOKING ZONDTION Oven lamp does not light at all

Oven lamp lights, but turntable motor does not operate

Cooling fan motor does not operate. After start pad is touched, the oven stops and

display shows “ADD”, “TURN”, “TABLE”

Oven does not go into cook cycle when START

pad is touched. Oven seems to be operating but little

MICROWAVE) or no heat is produced in oven load. (Food in-

completely cooked or not cooked at all at end of cook cycle.)

Oven goes into a cook cycle but extremely un-

even heating is produced in open load (food)

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Uven does not cook properly when programmed for variable cooking powers. (Oven operates

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properly at HIGH) Oven does not cook properly when programmed

in EASY DEFROST cooking mode. CONV indicator light, but oven does not go into

a cook cycle when START pad is touched.

ZONVECTION) CONV indicator light, but heating element does

not heat

Temperature in the oven cavity is lower or higher than preset.

Convection cycle runs 1 minute then shuts down.

I I I I I I

Convection

cycle

runs

3 minutes

then

shuts 1

1

1 1

1

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SENSOR)

Oven is in the sensor cooking condition but AH sensor does not end 1st stage or does not stop cooking cycle or the oven stops soon.

6

R-9200

.

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R-9ZOO

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

A

MAGNETRON TEST

’ NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED

!-

TOOL WHILE THE OVEN IS IN OPERATION.

-1

-----

CARRY OUT 3D CHECKS

Isolate the magnetron from the high voltage circuit by removing all leads connected to the filament

terminal.

To test for an open circuit filament use an ohmmeter to make a continuity test between the magnetron filament terminals, the meter should show a reading of less than 1 ohm.

To test for a short circuit filament to anode condition, connect ohmmeter between one of the filament terminals and the case of the magnetron (ground). This test should be indicated an infinite resistance. If a low or zero resistance reading is obtained then the magnetron should be re

(R lz

laced.

82AOl U)

MICROWAVE OUTPUT POWER (2 liter water load)

The following test procedure should be carried out with the microwave oven in a fully assembled condition (with outer case fitted). Microwave output power from the magnetron can be measured by way of substitution, i.e. it can be measured by using a 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 formula is as follows;

P x t / 4.2 = V x AT P (W) = 4.2 x V x AT/t

Our condition for the water load is as follows:

Room temperature . . . . . . . . . . . . . . . . . . . . . around

20°C

Power supply Voltage . . . . . . . . . . . . . Rated

voltage

Water load . . . ...2000 ml Initial temperature . . . . . . . 1 O+ 1 “C Heating time . . . . . . 1 min. 45 sec.

P=80xAT

Measuring method:

A) Use two 1 litre Pyrex beakers with a diameter of approximately of 12cms.

B) Place 1 litre of 10°C water in each beaker.

C) Mark Tl on the one beaker and mark T2 on the other one. And stir the water and measure the

temperature of water the thermometer and note them. The graduation of the thermometer must be scaled by 0. 1 “C at minimum and an accurate mercury thermometer is recommended.

D) Place the two beakers as touching each other in the centre of the cavity.

E) Set the timer to 1 minute and 45 seconds, at 100% power (the time required to raise the water

temperature 10 degrees C.) F) The time must be measured with stopwatch or wristwatch. G) After 1 minute and 45 seconds, stop the oven by opening the door. H) Remove the two beakers from the oven and measure the temperature of the water by stiring the

water with the thermometer and noting the readings.

Example

Initial temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tl =

10°C T2 = 11 “C

Temperature after 1 min. 45 set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tl = 20°C T2 = 21 “C

Temperature difference Cold-Warm s..........................................

AT1 = 10°C AT2 = 10°C

Mean temperature rise AT . . . . . . . .

AT = (AT1 +AT2) / 2 = (IO’C + IO’C) / 2 = 10°C Measured output power The equation is “P= 80 x AT”

*.........t....*.*.................................

P= 80 x 10°C = 800 Watts

NOTE: The measured output power should be at least +I5 % of the rated output

power.

CAUTION: 1 “C CORRESPONDS TO 80 WATTS.

REPEAT MEASUREMENT IF THE POWER IS INSUFFICIENT.

8

R -9200

TEST PROCEDURES (CONT’D)

PROCEDURE

LETTER

COMPONENT TEST

(Tl OC)

IT2 OC) (T2 OC)

Heat up for 1 min. 45 sec.

(RD82A02U)

MICROWAVE OUTPUT POWER (IEC-7054988)

The following test procedure should be carried out with the microwave oven in a fully assembled condition (outer case fitted). Microwave output power from the magnetron can be measured by way of IEC 705, 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/4.1 87 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 formula is as follows;

Pxt/4.187=VxAT P(W) =4.187xVxAT/t

Our condition for the water load is as follows:

Room temperature . . . . . . . . . . . . . . . . . . . . . around 20°C Power supply Voltage . . . . . . . . . . . . . Rated voltage

Water load . . . . . . . . 1000 g

Initial temperature . . . . . . . 10 +2”C Heating time . . . . . . . . . . . . . . . . 47 sec.

P=90xAT

Measuring condition:

1. Container The water container must be a cylindrical borosilicate glass vessel having a maximum material thickness of 3 mm and an outside diameter of approximately 190 mm.

2. Temperature of the oven and vessel The oven and the empty vessel are at ambient temperature prior to the start of the test.

3. Temperature of the water The initial temperature of the water is (10 + 2)“C.

4. Select the initial and final water temperature so that the maximum difference between the final water temperature and the ambient temperature is 5°C.

5. Select stirring devices and measuring instruments in order to minimize addition or removal of heat.

6. The graduation of the thermometer must be scaled by 0.1 “C a.

thermometer.

7. The water load must be (1000 + 5) g.

8. “t” is measured while the microwave generator is operating at fu

heat-up time is not included.

NOTE: The operation time of the microwave oven is “t + 2” sec.

heat-up time.

Measuring method:

t minimum and an accurate

I power. Magnetron filament

2 sec. is magnetron filament

1. Measure the initial temperature of the water before the water is added to the vessel. (Example: The initial temperature Tl = 11 “C)

2. Add the 1 litre water to the vessel.

3. Place the load on the centre of the shelf.

4. Operate the microwave oven at HIGH for the temperature of the water rises by a value A T of (10 + 2)“C.

5. Stir the water to equalize temperature throughout the vessel.

6. Measure the final water temperature. (Example: The final temperature T2 = 21 “C)

7. Calculate the microwave power output .FJ in watts from above formula.

9

R-9ZOO

TEST PROCEDURES (CONT’D)

PROCEDURE

LETTER

COMPONENT TEST

Initial temperature

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

Tl =

1 1 “C

Temperature after

(47 +

2) = 49 sec. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

T2 = 21 “C

Temperature difference

Cold-Warm = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

AT1

10°C

Measured output power The equation is “P= 90 x AT”

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P= 90 x 10°C = 900 Watts

JUDGMENT: The measured output power should be at least *I5 % of the rated

output power.

CAUTION: 1°C CORRESPONDS TO 90 WATTS. REPEAT MEASUREMENT IF THE POWER IS

INSUFFICIENT.

T2”C

Heat up for 49 sec.

(RD82A03U)

B POWER TRANSFORMER TEST

WARNING: High voltages and large currents are present at the secondary winding

and filament winding of the power transformer. It is very dangerous to work near this part when the oven is on.

NEVER make any voltage measurements of the high-voltage circuits, including the magnetron filament.

CARRY OUT 3D CHECKS.

Disconnect the leads to the primary winding of the power transformer. Drsconnect the filament and secondary winding connections from the rest of the HV circuitry. Using an ohmmeter, set on a low range, it is possible to check the continuity of all three windings. The following readings

should be obtained :-

Primary winding ----------less than 1 .I ohms.

k: Secondary winding -------65.5 ohms. .

c. Filament winding ---------less than 1 ohm,

If the reading obtained are not as stated above, then the power transformer is probably faulty and

should be replaced.

CARRY OUT 4R CHECKS

(RD82405J)

10

TEST PROCEDURES (CONT’D)

PROCEDURE

LETTER

COMPONENT TEST

0

RELAY TEST

Remove the outer case and check voltage between Pin Numbers 1 and 3 of the 3-pin connector (A) on the control 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 cooking or convection cooking operation.

DC. voltage indicated

. . . . . . . . . . Defective relay.

DC. voltage not indjcated

. . . . . . ..Check diode which is connected to the relay coil. If diode is

good, control unit is defective.

I

RELAY SYMBOL 1 OPERATIONAL

CONNECTED COMPONENTS

VOLTAGE

I

RYl

Approx. 18 V.D.C.

RY2(COOK)

Approx. 18 V.D.C.

RY3( HEATER)

Approx. 18 V. D.C.

RY4

Approx. 18 V. D.C.

RY5

Approx. 18 V. D. C.

RY6

Aoorox. 18 V.D.C.

Oven lamp and Turntable motor

Power transformer

Heating element

Damper motor Convection motor Coolina fan motor

P

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, this foil pattern serves as a substitute coil. If the foil pattern is open, follow the troubleshooting guide given below for repair.

Problem: POWER ON, indicator does not light UD.

STEPS OCCURANCE

CAUSE OR CORRECTION

1 The rated voltage is not applied to POWER terminal Check supply voltage and oven power cord.

of CPU connector (CN-A)

2 The rated voltage is applied to primary side of power Power transformer or secondary circuit defective.

transformer.

Check and repair.

3 Only pattern at “a” is broken.

‘Insert jumper wire 1 and solder.

4

Pattern at “a” and “b” are broken.

*insert the coil RCILF2003YAZZ between “c” and “d”.

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.

11

TEST PROCEDURES (CONT’D)

PROCEDURE

LETTER

COMPONENT TEST

WEIGHT SENSOR ASSEMBLY AND IC3(MEMORY) TEST.

After replacing the weight sensor or IC3, carry out the following procedure in order to calibrate the weight sensor. food mav be over or under cooked.

If the weight sensor is not recalibrate, the

The following procedure should be carried out with microwave oven in a fully assembled condition (with outer case fitted).

1. Place the turnrable on the turntable support plate correctly, and close the door.

2. Plug the oven into a power point. (“88:88” will appear on the display.)

3. Press the STOP/CLEAR pad. (Display shows M : II with sound of buzzer.)

4. Press the AUTO START/CLOCK pad. (Display shows fl

5. Press the GRILL pad. (Display shows II

0~)

0” with sound of buzzer.)

6. Press the POWER LEVEL pad. (Display shows fl

0~)

7. Press the INSTANT COOK/START pad. (Display shows ” TEST” with sound of buzzer.)

8. Press the “4” of number pads. (Display shows N DISH”

and oven lamps come on.)

with sound of buzzer, and tuntable

9. After 13 seconds, make sure that the display shows “25000 - 35000”” with sound of buzzer.

If display shows less than 25000 or more than 35000, weight sensor

10. Place the weight 2 Kg +2Og (water load 2 Kg +2Og) on the turntable.

is defect.

11. Press the “6” of number pads. (Display shows M DISH”

and oven lamps come on.)

with sound of buzzer, and turntable

12. After 13 seconds, make sure that the display shows “02300 - 02800”” with sound of

- buzzer.

If display shows less than 02300 or more than 02800, weight sensor is defect.

13. Disconnect the oven from power supply, and repeat above procedure items 1 to 7

14. Press the “7” of number pads, and make sure that the display shows “02300 - 02800”R.

If display shows less than 02300 or more than 02800, IC3 is defect,

12

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) Key Unit (2) Control Unit

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

Key Unit

The key unit is composed of a matrix, signals generated in the LSI are sent to the key unit through

POO,PO5,PlO,P13,P14,P22,P23 and P25.. When a key pad is touched, a signal is completed through the key unit and passed back to the LSI through RO-R3 to perform the function that was requested.

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)

1)

2)

3)

LSI

This LSI controls the temperature measurement signal, AH sensor signal, key strobe signal, relay driving signal for oven function and indicator signal.

(RD916Al U)

Power Source Circuit

This circuit generates voltages necessary for the control unit from the AC line voltage.

Synchronizing Signal Circuit

The power source synchronizing signal is available in order to compose a basic standard time in the clock circuit.

It incorporates a very small error because it works

on commercial frequency.

4)

5)

6.1

7)

8)

9)

ACL Circuit

A circuit to generate signals resetting the LSI to the

initial state when power is applied.

Buzzer Circuit

The buzzer is responds to signals from the LSI to emit noticeable sounds (key touch sound and completion sound).

Temperature Measurement Circuit(l): Oven

The temperature in the oven cavity is sensed by the thermistor. The variation of resistance according to sensed temperature is detected by the temperature measurement circuit and the result applied to LSI. The LSI uses this information to control the relay and display units.

Absolute Humidity Sensor Circuit

This circuit detects the humidity of the food which is being cooked, to control its automatic cooking.

Stop Switch

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

closed.

Relay Circuit

To drive the magnetron, heating element, fan motor, convection motor, damper motor and light the

oven lamp.

1

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 has 6-digits, 15-segments are used for displaying figures.

13

DESCRIPTION OF LSI

LSI(IZA413DR)

The I/O signals of the LSI(IZA413DR) are detailed in the following table.

PIN NO. 1 1

1 SIGNAL / VREF

I

I/O

IN

Reference voltage input terminal.

A reference voltage applied to the A/D converter in the LSI. Connected to GND.(OV)

(RD93GA6U)

PIN NO. 1 2

1 SIGNAL / IN7

I

I/O

1 IN

Terminal to change cooking constant.

PIN NO. 1 3 Signal similar to IN7

1 SIGNAL j

IN6

I

I/O

/ IN

PIN NO. / 4

1 SIGNAL j IN5

I

I/O

j IN

Signal similar to IN7

PIN NO. / 5

1 SIGNAL / IN4

I

I/O

1 IN

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

Damper opened; “H” level signal(OV:GND). / Damper closed; “L” level signal(-5V:VC).

(RD937A3U)

PIN NO. 6

1 SIGNAL / IN3

I

I/O

1 IN

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

Door closed; “H” level signal( / Door opened; “L” level signal(-5V).

PIN NO. 1 7

1 SIGNAL / IN2

I

I/O

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. j 8

1 SIGNAL j IN1

I

I/O

/ IN

AH sensor input.

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. / 9

1 SIGNAL ( IN0

I

l/O

j IN

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

from the AH sensor circuit,and connected to the A/D converter built into the LSI.

input is an analog input terminal

(RD936A3U)

PIN NO. / IO-14

1 SIGNAL ) P47-P43

I

I/O

j OUT

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

PIN NO. / 15

1 SIGNAL 1 P42

I

I/O

j OUT

Timinw sianal output terminal for temperature measurement(OVEN).

“H” level (GND) : Temperature measuring timing. (convection cooking) “L” level (-5V) : Thermistor OPEN timin!.

(RD935A7 )

PIN NO. j 16

Clock sinnal to K-3

1 SIGNAL / P41

I

I/O

1 OUT

14

PIN NO. 1 17

1 SIGNAL j P40

Magnetron high-voltage circuit drivinq signal.

To turn on and off the cook relay( RY2).

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 “L” level in repetition according to the power level.

I

I/O

/ OUT

H’GH L

MED HIGT+z{

MEP 3” lEr*c. J-J-i_

ME-) Low~lz’dpT-i_

PIN NO. j 18

-.

1 SIGNAL j P37

I

l/O

/ IN/OUT

Data sianal output from IC-3 and input to IC-3.

PINNO. I19

1 SIGNAL 1 P36

I

l/O

1 OUT

Cooling fan motor driving signal.

To turn on and off the shut-off relay( RY6).

“L”level during both microwave and convection cooking: “H” level otherwise

PIN NO. 1 20

1 SIGNAL 1 P35

I

I/O

1 OUT

Heating element driving signal.

To turn on and off the heater relay( RY3). “L” level during convection cooking; “H” level otherwise. During convection cooking, the signal becomes “H” level when the temperature of the oven cavity exceeds the predetermined temperature.

PIN NO. / 21

1 SIGNAL 1 P34

I

I/O

j OUT

Convection motor driving signal.

To turn on and off the shut-off relay( RY5). “L” level during CONVECTION; “H” level otherwise.

PIN NO. 1 22

1 SIGNAL 1 P33

I

l/O

j OUT

Oven lamp and Turntable motor driving siclnal(Square waveform:fiOHz).

To turn on and off the shut-off relay( RYI ). The square waveform voltage is delivered to the RYI

20 mnc.

c

driving circuit and relays (RY2,RY3,RY5) control

7-P* 1

- - r

----”

circuit.

- --

L

PIN NO. 1 23

1 SIGNAL j P32

I

I/O

/ OUT

Signal to sound buzzer.

0 1 WC

A:

Key touch sound. B: Completion sound. c: When the temperature of the oven cavity reaches the preset

temperature in the preheating mode, or when the preheating

hold time (I 5 minutes) is elapsed.

9

1

n CND

C

L

15

R -9200

PIN NO. j 24

1 SIGNAL / P31

I

I/O

%qnal to svnchronize LSI with commercial power source frequency.

This is basic timing for all real time processing of LSI.

ti rnGND

1

20 msac

PIN NO. j 25

1 SIGNAL / P30

I-

I

I/O

1 OUT

Damper motor relay drivinq siqnal.

To turn on and off the shut-off relay( RY4).

OFF

H GND

ON

,

---e--L

PIN NO. / 26 Connected to VC.

1 SIGNAL ) CNVSS

I

I/O

1 IN

(RD93KA3U)

PIN NO. 1 27

1 SIGNAL 1 RESET

I

I/O

) IN

Auto clear terminal.

Signal is input to reset the LSI to the initial state when power is applied. Temporarily set to “L” level the moment power is applied, at this time the LSI is reset. Thereafter set at “H” level.

(RD93MA2U)

PIN NO. / 28

1 SIGNAL 1 XIN

I

I/O

j IN

Internal clock oscillation frequencv settinq input.

The internal clock frequency is set by inserting the ceramic filter oscillation circuit with respect to XOUT terminal. PIN NO. / 29 1 SIGNAL / XOUT

I

I/O

1 OUT

Internal clock oscillation frequency control output.

Output to control oscillation input of XIN. PIN NO. 1 30 1 SIGNAL ( XCIN

I

I/O

1 IN

Weight sensor data input.

PIN NO. 31

I

1 SIGNAL 1 XCOUT

I

I/O

/ OUT

Terminal not used.

PIN NO. ,

1 32

1 SIGNAL 1 VSS

I

I/O

j IN

Power source voltaqe: -5V

VC voltage of power source circuit input. PIN NO.

1 33

1 SIGNAL ( 0

I

l/O

/ OUT

Terminal not used.

PIN NO. / 34

1 SIGNAL / R3

I

I/O

IN

Siqnal cominq from touch kev.

When any one of G-l

line keys on key matrix is touched, a corresponding signal from

POO,PO5,P1O,P13,P14,P22,P23 or P25 will be input into R3. When no key is touched, the signal is held at “L” level.

PIN NO. 35

SIGNAL / R2

I

I/O

IN

Sisnal similar to R3.

When any one of G-2 line keys on key matrix is touched, a corresponding signal will be input into R2.

(RD93CA8U)

PIN NO. 36

1 SIGNAL / RI

I

I/O

/ IN

Siqnal similar to R3.

When any one of G-3 line keys on key matrix is touched, a corresponding signal will be input into RI.

(RD93CA8U)

PIN NO. / 37

1 SIGNAL j RO

I

I/O

/ IN

Siqnal similar to R3.

When any one of G-4 line keys on key matrix is touched, a corresponding signal will be input into RO.

(RD93CA8U)

PIN NO. / 38

1 SIGNAL j VP

I

I/O

IN

Anode (seament) of Fluorescent Displav liqht-up voltaqe: -3lV. Vp voltage of power source circuit input.

16

PIN NO. 1 39 Terminal not used.

1 SIGNAL 1 PI7

I

I/O

1 OUT

PIN NO. j 40

1 SIGNAL 1 PI6

Segment data signals.

The relation between signals and indicators are as follows:

I

I/O

j OUT

Signal

Segment Sianal

Segment

PI6

..................................... LB2 PO2 .......................................... g

PI4

.................................... UB2 PO1 ........................................... f

PI 3

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

LB1

PO0

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

PI1

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

UBI

P26 ..........................................

PI0

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

k P25 ..........................................

PO7

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

PO5

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

i

P23

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

P22

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

-

PO4 ..........................................

h

PIN NO. j 41

1 SIGNAL j PI5

I

l/O

/ OUT

Digit selection signal.

The relationship between digit signal and digit are as follows:

Digit signal

digit

P15 . . . . . . . . . . . . . . . . . . . . . . . . . . 1st

P12 . . . . . . . . . . . . . . . . . . . . . . . . . . 2nd

PO6 . . . . . . . . . . . . . . .._..... . . . .3rd

PO3 . . . . . . . . . . . . . . . . . . . . . . . ...4th

P27 . . . . . . . . . . . . . . . . . . . . . . . . . . 5th

P24 . . . . . . . . . . . . . . . . . . . . . . . . . .

6th

Normally, one pulse is output in every 13 period, and input to the grid of the Fluorescent Display.

--- ---_--_______ GND

PO6 n

PO3 n

P27 n

P24 ---ki-L

PIN NO. 1 42 1 SIGNAL 1 PI4 1 I/O 1 OUT

Segment data signal.

Signal similar to P16.

Kev strobe signal.

Signal applied to touch-key section. A pulse signal is input to RO-R3 terminal

while one of G-5 line keys on key matrix is touched.

(RD939A3U)

PIN NO. 1 43 1 SIGNAL 1 PI3

I

I/O

1 OUT

Segment data siqnal. Key strobe signal.

Signal similar to PI 6.

Signal applied to touch-key section. A pulse signal is input to RO-R3 terminal while one of G-6 line keys on key matrix is touched.

(RD939A3U)

PIN NO. 1 44 1 SIGNAL / PI2

I

I/O

/ OUT

Digit selection signal. Signal similar to PI 5.

(RD938A2U)

PIN NO. / 45 1 SIGNAL 1 PI1

I

I/O

j OUT

Segment data signal. Signal similar to P16.

(RD939A2U)

PIN NO. 1 46

Seqment data signal.

Signal similar to P16.

1 SIGNAL 1 PI0

I

I/O

1 OUT

Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to RO-R3 terminal

while one of G-7 line keys on key matrix is touched.

(RD939A3U)

PIN NO. j 47

1 SIGNAL 1 PO7

Segment data signal. Signal similar to P16.

I

I/O / OUT

(RD939A2U)

17

PIN NO. 1 48

1 SIGNAL / PO6

Digit selection signal. Signal similar to PI 5.

I

I/O

1 OUT

CRD938A2U)

PIN NO. / 49

1 SIGNAL / PO5

I

I/O

j OUT

Segment data signal.

Signal similar to PI 6.

Kev strobe signal.

Signal applied to touch-key section. A pulse signal is input to RO-R3 terminal while one of G-8 line keys on key matrix is touched.

(RD939A3U)

PIN NO. 1 50

1 SIGNAL 1 PO4

I

I/O

/ OUT

Segment data siwal. Signal similar to P16.

(RD939A2U)

PIN NO. 1 51 Digit selection signal. Signal similar to PI 5.

1 SIGNAL j PO3

I

I/O

1 OUT

(RD938A2U)

PIN NO. j 52-53

1 SIGNAL / PO2-PO1

I

I/O

/ OUT

Segment data signal. Signal similar to P16.

tRD939A2U)

\ -

I

I/O

1 OUT

PIN NO. / 54

1 SIGNAL ( PO0

Segment data signal.

Signal similar to PI 6.

PIN NO. / 55

Dinit selection signal. Signal similar to PI 5.

Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to RO-R3 terminal while one of G-9 line keys on key matrix is touched.

(RD939A3U)

1 SIGNAL 1 P27

I

I/O

/ OUT

(RD938A2U)

PIN NO. 1 56 1 SIGNAL j P26

I

I/O

j OUT

Segment data signal. Signal similar to PI 6.

(RD939A2U)

PIN NO. 1 57

1 SIGNAL j P25

I

I/O

/ OUT

Serrment data sianal. Key strobe signal.

Signal similar to PI 6.

Signal applied to touch-key section. A pulse signal is input to RO-R3 terminal

while one of G-10 line keys on key matrix is touched.

(RD939A3U)

PIN NO. / 58

1 SIGNAL 1 P24

I

I/O

j OUT

Dinit selection signal. Signal similar to P15.

(RD938A2U)

PIN NO. / 59

1 SIGNAL j P23

I

I/O

1 OUT

Serrment data sinnal.

Kev strobe sianal.

Signal similar to PI 6.

Signal applied to touch-key section. A pulse signal is input to RO-R3 terminal while one of G-l 1 line keys on key matrix is touched.

(RD939A3U)

PIN NO. / 60

1 SIGNAL / P22

I

I/O

/ OUT

Secrment data sianal.

Kev strobe sianal.

Signal similar to PI 6. Signal applied to touch-key section. A pulse signal is input to RO-R3 terminal

while one of G-12 line keys on key matrix is touched.

(RD939A3U)

PIN NO. 1 61-62

1 SIGNAL j P21-P20

I

I/O

1 OUT

Terminal not used.

PIN NO. 1 63/64

1 SIGNAL / AVCC/VCC

I

I/O

j IN

Connected to GN D.

18

R-9Zoo

ABSOLUTE HUMIDITY SENSOR CIRCUIT

(1) Structure of Absolute Humidity Sensor

The absolute humidity sensor includes two thermistors as shown in the illustration. One thermistor 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.

(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 (RI and R2). The output of the bridge circuit is to be amplified by the operational amplifier.

Each thermistor is supplied with a current to keep it heated at about 150°C (302”F), the resultant heat is dissipated in the air and if the two thermistors are placed in different humidity conditions they show different degrees of heat conductivity leading to a potential difference between 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 is amplified by the operational amplifier.

b

Absolute humidity (g/m* 1

(3)Detector Circuit of Absolute Humidity Sen-

sor Circuit

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 clearing cycle occurs than the detector

circuit starts to function and the LSI observes the initial voltage available at its IN1 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 IN0 terminal of the LSI. The voltage of IN1 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 the sensor cooking proceeds, the food is heated

to generate moisture by which the resistance bal-

ance of the bridge circuit is deviated to increase the voltage available at IN1 terminal of the LSI. Then the LSI observes that voltage at IN1 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 in the next operation automatically. When the LSI starts to detect the initial voltage at

IN1 terminal 16 seconds after the unit has been put

in the Sensor Cooking mode, if it is not possible to

I

balance, of the bridge circuit due to disconnection of the absolute humidity sensor, ERROR will ap-

,

I

pear on the display and the cooking is stopped.

1 )Absolute humidity sensor circuit

IC2( IZA3 1 ODR)

--.-.

IT-z

--I4

SW1

620K

lo P47d

I5 11

9.

*

300K

‘6 12

P46pT

r

. P45s3,

150K

7 13

“1

I-

P44 s%

C. Thermtstor in 8

75K

16 14

SW5 “1

closed vessel

I ‘-

37.4K

I

P43 4

“1

S. Thermistor In

open vessel

I

IN0

VA:-1SV VA:

-15v VC: -5v

19

R-9200

1.

SERVICING

Precautions for Handling Electronic Components

This unit uses PMOS LSI in the integral part of the circuits. When handling 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 charge in clothes, etc,and sometimes it is not fully protected by the built-in protection circuit. In order to protect PMOS LSI.

1) When storing and transporting, thoroughly

wrap them in aluminum foil. Also wrap all PW boards containing them in aluminium foil.

2) When soldering, ground the technician as shown

in the figure

and use grounded

soldering iron and work table.

* .

J

approx. 1 MR

h

2. Shapes of Electronic Components

Transistor

288793

DTDl43EA

Transistor

DTA143ES DTBl43ES KRA102M KRCl02M

2SA933S

3. Servicing of Touch Control Panel

We describe. the procedures to permit servicing of

the touch control panel of the microwave oven and the precautions you must take when doing so. To perform the servicing, power to the touch control panel is available either from the power line of the oven itself or from an external power source.

(I) Servicing the touch control panel with

power supply of the oven:

CAUTION: THE HIGH VOLTAGE TRANSFORMER OF THE MICROWAVE OVEN IS STILL LIVE

DURING SERVICING PRESENT A HAZARD.

Therefore, when checking the performance of the touch control panel,put the outer cabinet on the oven to avoid touching the high voltage transformer, or unplug the primary terminal

(connector) of the high voltage transformer to

turn it off; the end of such connector must 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 itself is SO short that the two can’t be separated.

B.

For those models, check and repair all the controls (sensor-related ones included) of the touch control panel while keeping it connected to the oven. On some models, the power supply cord be-

tween the touch control panel and the oven

proper is long enough that they may be separated from each other. For those models,

therefore, it is possible 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 stop switch (on PWB) of the touch control panel with a jumper, which brings about an operational state that is equivalent to the oven door being closed. As for the sensor-related controls of the touch control panel, checking them is possible if dummy resistor(s) with resistance equal to that of the controls are 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 stop switch (on PWB) of the touch control panel,which brings about an operational state

that is equivalent to the oven door being closed. Connect an external power source to the power input terminal of the touch control

panel, then it is possible to check and repair the

controls of the touch control panel; it is also

possible to check the sensor-related controls

of the touch control panel by using the dummy resistor(s).

4. Servicing Tools

Tools required to service the touch control panel assembly.

1) Soldering iron: 30W (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

I>

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 connector of the key unit to the control unit being sure that the lead wires are not twisted.

After aluminum foil is removed, be careful that abnormal voltage due to static electricity etc. is not applied to the input or output terminals. Attach connectors, electrolytic capacitors, etc. to PWB, making sure that all connections are tight. Be sure to use specified components where high precision is required.

(‘RD94ZA2U)

20

R-9200

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

WARNING: To avoid possible exposure to microwave

energy;

A. Before operating the oven

1. Make sure that, when unlatching the door slowly, an accompanying “click” indicating the actuation of the monitor switch and latch switches is heard.

2. Check visually the door seal for arcing and damage.

B. Do not operate the oven before any of the follow-

ing conditions are repaired;

1.

Door does not close firmly against the front of

appliance.

2. There are a broken door hinge or support.

3. The door is bent or warped.

4. There is any defective parts in the interlock, oven door or microwave generating and transmission assembly.

5. 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 VO LTAG E

CAPACITOR

BEFORE TOUCHING ANY OVEN COMPONENTS OR WIRING.

(RDAI 203U)

OUTER CASE REMOVAL

To remove the outer case, proceed as follows.

::

3.

1.

2.

3.

4.

Disconnect oven from power supply. retaining clips on the cavity face plate. Remove the eight (8) screws from rear and along

5. Lift the entire case from the oven.

the side edge of case.

CAUTION: DISCHARGE

HIGH

VO LTAG E

Remove the two (2) screws from the lower portion

CAPACITOR BEFORE TOUCHING ANY

of the oven cabinet back side.

OVEN COMPONENTS OR WIRING.

OVEN LAMP SOCKET REMOVAL

Pull the wire leads from the oven lamp socket by

. . . . . . -.

pushing the termtnal hole ot the oven lamp socket

with the flat type small screw driver.

Lift up the tab of the oven lamp mounting plate holding the oven lamp socket. Slide the oven lamp socket left-ward. Now, the oven lamp socket is free.

CAUTION: When replacing the oven lamp socket, re-

place it so that the side where the black dot is put faces left-ward.

4. Slide the entire case back about 3cm to free it from

Own lrmp socket

-

Oven lamp socket

21

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