Sharp R-7280, R-1720 Service Manual

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Page 1

R-7280 R-1720

SHARP SERVICE MANUAL

S6703R7280J//

MICROWAVE OVEN

MODELS R-7280

R-l 720

Photo R-7280

in the interests of user-safety the set should be restored to its original condition and only parts identical to those specified should be used.

( RD16101 U)

TABLE OF CONTENTS

FOREWORD

Page

. . . . . . . . . . . ..*.....*...........*................*......................................................................................................

CAUTION, MICROWAVE RADIATION

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..*...........................*..........

PRODUCT DESCRIPTION

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..*.......*..........................

OPERATION

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

SERVICING

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..*......................................................................

TOUCH CONTROL PANEL ASSEMBLY

. . . . . . . . . . . . . . . . . . . . . . . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

COMPONENT

REPLACEMENT

AND

ADJUSTMENT PROCEDURE

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

MICROWAVE MEASUREMENT PROCEDURE

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

PICTORIAL DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..........

CONTROL PANEL CIRCUIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..a.... . . . ..a..... . . . . . . . ..,.....a... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

PRINTED WIRING BOARD

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..~.............................................................

PARTS LIST

*........................................................................................................,.......................................... 29

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

SHARPCORPORATION

Page 2

R -7280 R -1720

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Photo R-l 720

Page 3

R-7280 R-1720

SERVICE MANUAL

MICROWAVE OVEN

R-7280/ R-1720

FOREWORD

This Manual has been prepared to provide Sharp Corp. Service

Personnel with complete Operation and Service information for

the SHARP MICROWAVE ovens, R-7280/ R-1720.

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 attention 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 ener ized.

( 1 036201 U)

SHARPCORPOf?ATK)N

OSAKA, JAPAN

(RD

37201 U)

Page 4

R -7280 R-l 720

PRODUCT DESCRIPTION

EXPLANATION OF MICROWAVE COOKING

The Sharp Microwave Oven uses microwave energy to produce heat in the food to be cooked. Unlike conventional ovens microwave energy will cook foods without applying external heat.

moisture content, like most foods, will absorb microwave energy. As the microwave energy at a frequency of 2450 Megahertz enters the food, the molecules align themselves with the energy. Because the microwaves are changing polarity every half cycle, the food mole-

Microwaves, which are short electromagnetic waves of RF (radio frequency) energy, pass through materials such as glass, paper, china and most plastics. Materi-

als such as metal and aluminum foil tend to reflect

microwaves and may be used only as recommended in

cules are changing direction every half cycle or oscillating back and forth 4,900,000,000 times per second. This high speed oscillation causes friction between the molecules, thereby converting the microwave energy to heat.

(RD41101U)

the cooking instructions.

Materials with a high

SPECIFICATION

ITEM

I DESCRIPTION

Power Requirements

240 Volts i 50 Hertz / Single phase, 3 wire earthed

j 13oow

-___

Power Consumption

-___

- --

Power Output ~~-~650 watts nominal ofRF microwave energy (2 liter water load)

j Operating frequency of 2450MHz

-______

-__

Case Dimensions

I , Width 520 mm

/ Height 318 mm including foot ’ Depth 393 mm

-------

-~-~

Cooking Cavity Dimensions

Width 345 mm

- --__

Control Complement

1 Height 217 mm 1 Depth 364 mm

_-__---__- -____i Touch Control System !

Timer (0 - 99 min 99 sec. ) : Microwave Power for Variable Cooking I

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

INSTANT COOK/START COOKING

1 AUTO START COOKING /

EASY DEFROST

EASY REHEAT

/ MORE/LESS pad

- Set Weight

-1 Approx. 17.5 kg

(RD44101

NOTE:

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

Page 5

R-7280 R-l 720

OVEN DIAGRAM

1. Ventilation openings

2. Oven lamp

3. Oven door with see through window

4. Removable turntable

5. Roller Stay

Auto-TouchTM Control Panel

1 Dinner plate 1-2plates

3 CasserolelSuup I-dcups

7 II nMEDLOWIIt-

8 11 nMED

I /I

&~++jq, f

INSTANT COOK

/ ::.fii3 j( START /A

-- I-

k:---./

/ 1

6 7 8 9

11.

Door latches

Door open button Auto-Touch Control Panel Digital readout Waveguide cover Access cover for oven lamp replacement

Door hinges

NUMBER PADS

EASY REHEAT PAD

EASY DEFROST PAD

VARIABLE COOKING CONTROL PADS

MORE ( A 1, LESS ( v ) PADS

AUTO START/CLOCK PAD

TIMER/HOLD PAD

INSTANT COOK/START PAD

STOP/CLEAR PAD

Page 6

R-7280 R-1720

COOKING CONDITION

HIGH COOKING CONDITION

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:

The contacts of relays*are closed and components connected to the relays are turned on as follows.

(For details, refer to Figure O-2)

RELAY

CONNECTED COMPONENTS

RY-1

oven lamp/turntable motor/fan motor

RY-2

power transformer

240 volts A.C. is supplied to the primary winding of the power transformer and is converted to about

3.5 volts A.C. output on the filament winding, and approximately 1900 volts A.C. on the high voltage winding. The filament winding voltage heats the magnetron

filament and the H.V. voltage doubler circuit.

winding voltage is sent to a

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.

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

The

OPERATION

DESCRIPTION OF OPERATING SEQUENCE

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

(RD71101U)

OFF CONDITION

Closing the door activates both door latch switches:

upper latch switch and lower latch switch. (In this condition, the monitor switch contacts are opened.) The stop switch is activated by the latch head. When oven is plugged in, 240 volts AC. is supplied to the control unit. But no components in the oven will operate.(Figure o-1 .) Note: When the door is opened by pushing the door

open button, the contacts of the relay RY-1 are

closed, then the oven lamp lights.

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.

6. When the door is opened during a cook cycle, monitor switch, upper latch switch and lower latch switch are activated with the following results. The circuits to the turntable motor, the cooling fan mo-

tor, and the high voltage components are deenergized, the oven ‘lamp remains on, and the digital readout displays the time still remaining in the cook cycle when the door was opened. The monitor switch is electrically monitoring the operation of the upper latch switch and is mechanically associated with the door so that it will func-

tion in the following sequence.

When the door opens from a closed position, the stop switch, upper and lower latch switches first operate to open their contacts, and then the monitor switch contacts close.

When the door is closed from the open position, the monitor switch contacts first open, and then the contacts of the stop switch, upper and lower latch switches close.

case the upper latch switch fails with its contacts closed when the door is opened, the monitor switch will form a short circuit through the monitor fuse, and the upper latch switch, causing the monitor fuse to blow.

MED HIGH, MED, MED LOW DEFROST, LOW 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 30 second time base. Microwave power operation is as follows:

VARI-MODE

HIGH (100% power)

MED HIGH (approx. 70wpower)

MED (approx. 50% power)

MED LOW DEFROST (approx. 30% power)

LOW (approx. 10% power)

ON TIME

OFF TIME

32 sec.

-2 sec.

24 sec.

6 sec.

18 sec.

12 sec.

18 sec.

6 sec.

24 sec.

Note: The ON/OFF time ratio does not correspond

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

(RD71401 U)

Page 7

R-7280 R-l 720

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Page 8

R-7280 R-1720

DESCRIPTION AND FUNCTION OF COMPONENTS

UPPER LATCH SWITCH

The switch is activated by the upper latch head on the door while the door is closed. When the door is opened, the switch interrupts the circuit (except oven lamp).

LOWER LATCH SWITCH

The switch is activated by the lower latch head on the door. When the door is opened, the switch interrupts

the circuit to transformer.

A cook cycle cannot take place until the door is firmly closed and the INSTANT COOK/START pad touched.

STOP SWITCH

The stop switch is located on latch hook and activated

by the lower latch head and switch lever. When the open button is depressed while the oven is in cook cycle, the stop switch contacts open to de-energize the relay( RY-1 ) and relay( RY-2) circuits in the control and causes cook time count down to pause.

MONITOR SWITCH

The monitor switch is activated (the contacts of “NC” opened) by the upper latch head on the door while the door is closed. The switch is intended to render the oven inoperative by means of blowning the monitor fuse when the contacts of the upper latch switch fail to open when the door is opened.

Functions:

1. When the door is opened, the monitor switch

normal close contacts (to the ON condition) due to their being normally closed. At this time the upper latch switch is in the OFF condition (con-

tacts open) due to their being normally open con-

tact switch.

2. As the door goes to a closed position, the monitor

switch normal close contacts are first opened and

then the upper latch switch contacts close and

lower latch switch contacts, (On opening the door, each of these switches operate inversely.)

3. If the door is opened, and the upper latch switch

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

CAUTION:BEFORE REPLACING A BLOWN MONI-

TOR FUSE, TEST THE UPPER LATCH FOR

PROPER OPERATION. (REFER TO CHAP-

TER “TEST PROCEDURE”).

DOOR OPEN MECHANISM

The door can be opened by pushing the open button on the control panel, refer to the Figure D-l. When the open button is pushed, the cook switch lever on the latch hook is moved upward, operating the latch head. The latch head is moved upward, and released from the latch hook. Now, the door can be opened.

OVEN LAMP

The oven lamp illuminates the interior of the oven so that food being cooked can be examined visually through the door window without having to open the door.

COOLING FAN MOTOR

The cooling fan motor drives a blade which draws cooling air through the back vents. This cooling air is directed through the air vanes sur-

rounding the magnetron and cools the magnetron. This air is channeled through the oven cavity to remove steam and vaports given off from the heating foods.

It is then exhausted at the back of the oven cavity.

MAGNETRON TEMP. FUSE

The temp. fuse located on the oven cavity is designed to prevent damage to the magnetron 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 temp. fuse remains closed.

However, when abnormally high temperatures are

reached within the magnetron, the fuse will open, causing the oven to shut down. This is a fuse and it does not reset.

OVEN TEMP. FUSE

When foods in oven cavity fire, oven temperature fuse stops ventilating from fan motor and extinguishes fire

in oven cavity before fire goes outside the unit,

MONITOR SWITCH

UPPER

LATCH

SWITCH

LOWER LATCH SWITCH

BUTTON

Figure D-1. Latch Switches Adjustment

Page 9

R-7280 R-1720

SERVICING

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 Procedures section.*’

IMPORTANT: If the oven becomes inoperative because of a

blown fuse in the monitor-upper latch switch circuit, check the monitor switch and upper latch switch before replacing the fuse.

PROBLEM -

POSSIBLE CAUSE

TEST PROCEDURE OR

CORRECTION

Home fuse blows when power cord

is plugged into wall receptacle.

Oven fuse blows when power cord is plugged into wall receptacie.

” 88:88 ” does not appear in display

when power cord is first plugged

into wail outlet.

Display does not operate properly when STOP/CLEAR key is touched. (Buzze should sound and time of day should uppar in display.)

Oven lamp does not light with door opened.

OFF CONDITION

Shorted wire in power cord or wire harness.

Shorted wire in power cord or wire harness,

Oefective monitor switch.

NO power at outlet.

No power from service entrance.

Open wire in power cord or wire harness.

Blown fuse.

Defective temp. fuse. (magnetron and oven)

Open wire In power cord, wrrmg harness,

or wrring between control panel assembly unrts.

Replace cord or check wiring.

Replace power cord or check

and repair wire harness.

Procedure H.

Check home fuse.

Check wall outlet.

Replace same or repair wiring.

Procedure I.

Procedure G.

Replace or reparr wiring.

Defective controi unit.

Procedure J.

Defective key untt. Procedure J.

Defective stop switch.

Procedure F.

Defective control unit.

Procedure J.

Defective oven lamp.

Replace oven lamp.

Defective stop switch.

Procedure F.

Defective control unit.

Procedure J.

Open or loose wire connection to the above

Check wiring.

components.

COOKING CONDITION

Oven lamp does not light in cook cycle. (Do light when door is opened.)

Defective relay RY-1 on control unit.

Procedure J.

Page 10

R-7280 R-1720

TROUBLESHOOTING GUIDE (CONT’D)

PROBLEM

POSSIBLE CAUSE

TEST PROCEDURE OR

CORRECTION

COOKING CONDITION (CONT’D)

Oven lamp does not light at all.

Cook indicator appears in display but turntable motor does not operate.

Burned out bulb.

Open wiring to oven lamp socket.

Defective relay RY-1 on control unit.

Turntable motor defective.

Replace oven lamp.

Check and repair wiring.

Procedure J.

Replace motor.

Open or loose wiring between control unit and motor.

Check and repair wiring.

Oven lamp lights but fan motor does not operate.

(Turntable motor does operate)

Defective fan motor.

Procedure E.

Open or loose wiring to fan motor.

Check and repair wiring.

Oven does not go into cook cycle when INSTANT COOK/START key is touched.

Upper and Lower latch switches and STOP switch defective or out of adjustment.

Blown Fose

Procedure F.

Procedure I.

Defective temp. fuse. (Magnetron and Oven)

Procedure G.

Defective relay RY-1, RY-2 on control unit.

Procedure J.

Defective control unit.

Defective key untt.

Open or loose wiring to the above

components.

Defective magnetron.

Defective relay RY-2 on control unit.

Defective power transformer.

Defective rectifier.

Defective high voltage capacitor.

Procedure J.

Check and repair wiring.

Procedure A.

Procedure J.

Procedure 8.

Procedure C.

Procedure 0.

Oven seems to be operating but little or no heat is produced in

oven load. (Food incompletely cooked or not cooked at all at end of cook cycle)

I t

Defective control unit.

Procedure J.

Open or loose wiring to the above components.

Check and repair wiring.

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

Turntable motor does not operate.

Replace turntable motor.

Oven does not cook properly when cooking control set to LOW, MED

LOW, MED, MED HIGH cooking

powers. (Operates properly on HIGH.)

Defective control unit.

Defective key unit.

Open or loose wiring between the above

components.

Procedure J.

Check and repair wiring.

Page 11

R-7280 R-1720

PROBLEM

POSSIBLE CAUSE

TEST PROCEDURE OR

CORRECTION

EASY DEFROST condition touching

Programmed incorrectly

INSTANT COOK/START Pad,

EASY DEFROST wile only operate

“ERROR” appears.

on a specific weight. Range for each food category. See staps for Easy Defrosy is

Operation Manual.

AH sensor open and/or short.

Defective control unit.

Procedure 0.

Procedure J.

Page 12

R -7280 R-1720

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

MAGNETRON ASSEMBLY TEST

DlSCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPONENTS 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 fiiament

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: rectifier, high voltage capacitor, heater transformer 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;

P x t / 4.2

=Vx AT

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

Our condition for the water load is as follows:

Water load . . . 2000 ml, Heating time . ..I 27 seconds

P = 66 x 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 127 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)=66x AT(X)

AT = ( ATL + ATR) / 2 : average temperature rise ATL = (TL2 - TLI),

ATR = (TR2 - TRl)

TL2 : water temperature after heating in left beaker TLl : 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. I. Initial temperature of salt water should be IO + 1 “C. (The salt water should be contained

bon (1) percent of salt.) 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.

Page 13

R-7280 R-1720

TEST PROCEDURES (CONT’D)

PROCEDURE

LE-ITER

COMPONENT TEST

4. Room temperature should be around 20 “C.

5. Power supply voltage should be specification voltage.

POWER TRANSFORMER TEST

DISCHARGE THE HIGH VOLTAGE CAPACiTAOR BEFORE TOUCHING ANY OVEN COMPONENTS 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 less than 1.47 ohms and the resistance of the high voltage coil should b approximately 100 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 SILICON RECTIFIER TEST

DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPONENTS OR WIRING.

Isolate the 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 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 rectifier is probably defective and should be replaced.

(R082501 U\

HIGH VOLTAGE CAPACITOR TEST

DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPONENTS OR WIRING.

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 10M R once the capacitor is charged. If the above is not the case, check the capacitor with an ohmmeter to see if it is shorted between the terminals. If it is shorted, replace the capacitor.

(RD82603U1

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 i Common Tekknal- Normally Open Terminal

I (COM) (NOI

Common Terminal-Normally Close Terminal

(COM)

)

Operation

(NC)

Plunger released i

Open circuit

Close circuit

1 Plunger pushed j

Closed circuit

Open circuit

------i

(RD82701 U)

Page 14

R-7280 R-1720

TEST PROCEDURES (CONT’D)

PROCEDURE

LETTER

COMPONENT TEST

F MAGNETRON AND OVEN TEMP. FUSE TEST

A continuity check across the temp. fuse terminals should indicate a closed circuit unless the temperature of the temp. fuse reaches approximately 145 “C. An open magnetron temp. fuse indicates overheating of the magnetron assembly. if the temp. fuse indicates a open circuit, replace the temp. fuse and check for restricted air flow to the magnetron through the opening in the chassis, especially the air duct and fan motor. An open oven temp. fuse indicate overheating of oven cavity. If the oven temp.fuse indicates aopen circuit, replace the oven temp.fuse and check the reason of the oven heating and check the wiring etc.

MONITOR SWITCH TEST

Before performing this test, 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 cirqit. When the monitor switch actuater is pushed by a screw driver through the lower 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, the switch may be defective.

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

(RD82803U)

UPPER

LATCH SWITCH

WHITE

BLUE

MONITOR

CO&l

OHMMETER

MONITOR SWITCH

UPPER LATCH

SWITCH

LOWER LATCH SWITCH

_-STOP

SWITCH

. SWITCH

LEVER

BLOWN OVEN FUSE

If the oven fuse in the upper latch switch-monitor switch circuit is blown when the door is

opened, check the upper latch switch and monitor switch before replacing the blown fuse. If the oven fuse is blown by improper switch operation, replace the defective switch and oven

fuse at the same time. Replace just the oven fuse if the switches operate normally. CAUTION; REPLACEMENT FUSE MUST BE THE LISTED FUSE IN PARTS LIST.

Page 15

R-7280 R-l 720

TEST PROCEDURES (CONT’D)

PROCEDURE

LETTER COMPONENT TEST

I TOUCH CONTROL PANEL ASSEMBLY TEST

The touch control panel consists of circuits including semiconductors such as LSI, KS, etc. Therefore, unlike conventional microwave ovens, proper maintenance cannot be performed with

only a voltmeter and ohmmeter. Troubleshooting by unit replacement is described according to

the symptoms indicated.

Control Unit

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

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. In connection with indicators a) At a certain digit, all or some segments do not appear. b) At a certain digit, brightness is low when it appears. c) Only one indicator does not appear. d) The corresponding segments of all digits do not appear; or they continue to appear. e) Wrong figure appears. f) A certain group of indicators do not appear. g) The figure of all digits flicker.

3. Other possible troubles caused by a defective control unit. a) Buzzer does not sound or continues to sound. b) Cooking is not possible.

Page 16

R-7280 R-1720

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.

(RD911A3U)

Key Unit

The key unit is composed of a matrix, signals generated in the LSI are sent to the key unit through P62, P63 and P70-P73.

When a key pad is touched, a signal is completed through the key unit and passed back to the LSI through PIO-PI 3 to perform the function that was re-

quested.

Control Unit

Control unit consists of LSI, power source circuit,

synchronizing signal circuit, ACL circuit, buzzer circuit

and indicator circuit.

(RD915Bl U)

LSI

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

(RD916Al U)

Power Source Circuit

This circuit generates voltage necessary in the control unit.

Symbol Voltage Application

VDD -12v

VREF

LSI (lC1 ), ACL circuit

-6.15V LSI (ICI)

-29V Fluorescent display tube : Grid

VF+ -18V

and anode voltage Filament of fluorescent display tube

VF- -2lV

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.

(RD918Al U)

ACL Circuit

A circuit to generate a signal which resets the LSI to the initial state when power is supplied.

(RD919Al U)

Buzzer Circuit

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

(RD91 AA1 U)

Stop Switch

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

(RD91 BA2U)

Relay Circuit

To drive the magnetron, fan motor, turntable motor and light’the oven lamp.

(RD91 CB2U)

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 6-digits, 13-segments are used for displaying figures.

(RD91 DA1 U)

Page 17

R-7280

R-1720

DESCRIPTION OF LSI

LSI(IZA086DR)

The I/O signal of the LSI(IZA086DR) is detailed in the following table.

(RD93101 U)

PIN NO. j 1-4

1 SIGNAL

/ P30-P33

I/O

/ OUT

Seament data sianals.

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 fluorescen;t$,$sl;

PIN NO. / 5

1 SIGNAL ! ACL

I/O

1 IN

Auto clear terminal.

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 6

1 SIGNAL ( CL1

l/O

1 IN

Internal clock oscillation frecluencv input settinq.

The internal clock frequency is set by inserting the ceramic filter oscillation circuit with respect to CL2 terminal.

(RD93EA2U)

PIN NO. / 7

1 SIGNAL / CL2

Internal clock oscillation freauencv control output.

Output to control oscillation input of CL1 .

I/O

/ OUT

(RD93EAl U)

PIN NO. / 8

1 SIGNAL / P40

I/O

/ OUT

Seament data sianal.

Signal similar to P30.

(RD939A2U)

PIN NO. / 9 1 SIGNAL / TEST

I/O i IN

Terminal not used. Connected to VDD.

(RD93KA4U)

PIN NO. 1 lo-13

Secrment data signal.

Signal similar to P30.

1 SIGNAL j P41-P43,P50

l/O

1 OUT

.( RD939A2U)

PIN NO. i 14

1 SIGNAL / P51

I/O

/ IN

Terminal to chanae functions accordinrr to the model.

Signal in accordance with the model in operation is applied to set up its function. Terminal not used.

(Rd93JAl U)

PIN NO. / 15

Terminal not used.

1 SIGNAL 1 P52

I/O

) IN

(RD93KA2U)

Page 18

R-7280 R-1720

PINNO. j 16

1 SIGNAL / P53

l/O

1 IN

Terminal for manufacture test.

Normally terminal not used.

(RD93lA3U)

PIN NO. / 17,18 Terminal not used.

1 SIGNAL j P6O,P61

I/O

j IN

(RD93KA2U)

PINNO. j 19 1 SIGNAL / P62 I

I/O

j OUT

Key strobe sianal.

Signal applied to touch-key section. A pulse signal is input to PI O-P1 3 terminal while one of G-l line keys on key matrix is touched.

(RD93BAl U)

PIN NO. / 20

1 SIGNAL j P63

l/O 1 OUT

Kev strobe signal.

Signal applied to touch-key section. A pulse signal is input to Pl O-PI 3 terminal while one of G-2 line keys on key matrix is touched.

(RD938Al U)

PIN NO. / 21

1 SIGNAL 1 P70

l/O

1 OUT

Kev strobe sinnal.

Signal applied to touch-key section. A pulse signal is input to PlO-PI3 terminal while one of G-3 line keys on key matrix is touched.

(RD93EAl U)

PIN NO. j 22

1 SIGNAL / P7l

I/O

j OUT

Kev strobe siQnal.

Signal applied to touch-key section. A pulse signal is input to Pl O-PI 3 terminal while one of G-4 line keys on key matrix is touched.

(RD938Al U)

PIN NO.

j 23

1 SIGNAL j P72

l/O

j OUT

Kev strobe signal.

Signal applied to touch-key section.

A pulse signal is input to PIO-PI3 terminal while one of G-5 line keys on key matrix is touched.

(RD93BAl U)

PIN NO. j 24

1 SIGNAL i P73

I/O

j OUT

Kev strobe signal.

Signal applied to touch-key section. A pulse signal is input to Pl O-PI 3 terminal while one of G-6 line keys on key matrix is touched.

(RD93BAl U)

PIN NO.

/ 25

Terminal not used.

1 SIGNAL 1 KT

I/O

/ IN

(RD93KA2U)

PIN NO.

! 26

1 SIGNAL 1 KI

I/O

/ IN

Sianal svnchronized with commercial source frequencv(50Hz).

This is the basic timing for time processing of LSI.

(RD93FE! U)

Page 19

R-7280 R-1720

PIN NO. 1 27

1 SIGNAL j SO

I/O

j OUT

Sinnal to sound buzzer.

A: Key touch sound (0.12 sec.). 6: Completion sound (2.4 sec.).

(RD93LAl U)

PIN NO. j 28

1 SIGNAL / NC

I/O

’ NC

Terminal not used.

(RD93KA2u)

PIN NO. / 29

1 SIGNAL 1 VDD

Power source voltage: -72V.

VDD voltage of power source circuit input.

l/O

/ IN

(RD93GAl U)

PIN NO. ! 30

Terminal not used.

1 SIGNAL 1 P80

I/O

/ OUT

(RD93KA2U)

PIN NO. j 31

1 SIGNAL j P81

I/O

I IN

Terminal not used. No connection.

(RD93KA7U)

PIN NO. / 32 Connected to GND.

SIGNAL / GND

l/O

’ IN

(RD93KA? U)

PIN NO. 1 33

1 SIGNAL j P82

I/O

j OUT

Terminal not used. Connected to GND.

(RD93KA5U)

PIN NO.

1 34

1 SIGNAL / P83

Terminal not used. Connected to GND.

I/O

1 OUT

(RD93KA5U)

PIN NO. / 35-38

1 SIGNAL j P90-P93

I/O

j OUT

Terminal not used. Connected to GND.

(RD93KASJ)

PIN NO. 1 39 1 SIGNAL j PO0

l/O

1 IN

Terminal not used. Connected to GND.

(RD93KA5U)

PIN NO. / 40 1 SIGNAL / PO1

I/O

1 IN

Terminal to chancre functions accordinQ to the model.

By using the A/D converter contained in the LSI. DC voltage in accordance with the model in operation is applied

to set up its function.

(Rd93JA2U)

PIN NO.

j 41

1 SIGNAL ( PO2

Terminal not used. Connected to GND.

I/O

/ IN

(RD93KA5U)

Page 20

-7280

: -1720

PIN NO, j 42

I SIGNAL j- P~~-~~ ~~

1 I/O i IN . ~ ~~~~~

Terminal to chanae functions according to the model.

By using the A/D converter contained in the LSI. DC voltage in accordance with the model in operation is applied

to set up its function.

(Rd93JA2U)

PIN NO. j 43 1 SIGNAL j PlO

l/O

j IN

Siqnal comincl from touch kev.

When either one of G-l 2 line keys on key matrix is touched, a corresponding signal out of P70-P73,P63 and P62 will be input into PI 0. When no key is touched, the signal is held at “L” level.

(RD93CAl U)

PIN NO. 1 44

1 SIGNAL / Pll

I/O

( IN

Sional comino from touch kev.

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

(RD93CA2U)

PIN NO. j 45

I SIGNAL \ P12

1 l/O i IN

~ ~ ~~

Signal comino from touch kev.

When either one of G-l 0 line keys on key matrix is touched, a corresponding signal will be input into P12.

(RD93CA2U)

PIN NO. 1 46 1 SIGNAL / P13

I/O

/ IN

Signal comino from touch kev.

When either one of G-9 line keys on key matrix is touched, a corresponding signal will be input into P13.

(RD93CA2U)

PIN NO.

j47 *

Connected to GND.

1 SIGNAL / AGND

l/O

/ IN

(RD93KAl U)

PIN NO.

/ 48-53 1 SIGNAL

i PA9-PA4

I/O

j OUT

Diait selection sinnal.

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 display.

(RD9 8Al

)

PIN NO. / 54

1 SIGNAL j PA3

l/O

/ OUT

Oven lamp, turntable motor and cooling fan motor driving signal. (Square Waveform: 50Hzl

To turn on and off the control relay. The pulse signal (50Hz) is delivered to the control relay driving circuit and cook relay control circuit.

(RD932El U)

PIN NO.

j 55

1 SIGNAL / PA2

Maonetron Hiah-voltaae circuit drivinn sicrnal.

To turn on and off the cook relay.

I/O

/ OUT

In HGH operation, the signals holds “H” level during microwave cooking and “L” 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.

(RD933Al U)

Page 21

R-7280 R-l 720

PIN NO. j 56

1 SIGNAL j VDISP

I I/O

1 IN

Anode (seclment) of Fluorescent Displav light-ur, voltage: -29V.

Vp voltage of power source circuit input.

(RD93GA3U)

PIN NO. j 57

1 SIGNAL j VR

Reference voltage input terminal.

I/O -rK

A reference voltage applied to the A/D converter in the LSI. The reference voltage is generally maintained at -6.15V.

(RD93GA4U)

PIN NO. j 58

1 SIGNAL / PA1

I/O

1 IN

Signal svnchronized with commercial source frequencv(50Hz).

This is the basic timing for time processing of LSI.

(AD93FE1 U)

PIN NO. j 59

1 SIGNAL f PA0

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.

(RD937Al U)

PIN NO. ( 60-63

1 SIGNAL

/ PZO-P23

l/O

; OUT

Senment data signal.

Signal similar to P30.

(RD939AZU)

PIN NO.

1 64

i SIGNAL 1 GND

I l/O

/ IN

Connected to GND.

(RD93KAl U)

Page 22

R-7280 R-1720

SERVICING

1, Precautions for Handing Electronic

Components

This unit uses PMOS LSI tn 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.

In 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.

2. Shapes of

Electronic Components

Regurator IC AN79L12

Transistor

1 : QUT Terminal 2 : COMMON Terminsl 3 : IN Terminal

tl\,brid !C IC 3

Transistor 2SA885A

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.

(1) 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 SERVICING.

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 transformer to turn it off; and the end of such connector 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 models, 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 stop 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 stop switch (on PWB) of the touch control panel,which brings about an operational 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).

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:

- IOMHz type or more ad-

vanced model.

3) Others:

Hand tools

Other Precautions

1) Before turning on the power source of the control unit, remove the aluminum foil applied

for preventing static electricity.

2) Connect the connectors of the indicator and

key units to the control unit taking care that the

lead wires are not twisted.

3) After aluminum foil is removed, take extra care

that abnormal voltage due to static electricity

etc. is not applied to the input or output terminals.

4) Attach connectors, electrolytic capacitors, etc. to PWB, taking care that all connections are tight.

5) Be sure to use specified components where high precision is required.

Page 23

R-7280 R-1720

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

WARNING: To avoid possible exposure to microwave

energy;

A. Before operating oven

1. Make sure that unlatching door slowly is accompanied by a click indicating actuation of monitor switch and latch switch.

Check visually door seal for arcing and damage.

B. Do not operate oven until after repair if any of fol-

lowing conditions exist;

1. Door does not close firmly against front of appliance.

2. There is a broken door hinge or support.

3. The door is bent or warped.

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

5. There is any other visible damage to oven.

C. Do not operate oven

1. Without the RF gasket.

2. If door is not closed.

( RDA1204U)

OUTER CASE REMOVAL

To remove the comoonents. proceed as follows.

Disconnect oven’ from power supply. Remove screws from rear and along the side edge of case. Slide the entire case back about 3cm to free it from retaining clips on the cavity face plate.

4. Lift entire case from the unit. CAUTION: DISCHARGE HIGH VOLTAGE

CAPACITOR BEFOR TOUCHING ANY OVEN COMPONENTS OR WIRING.

HIGH VOLTAGE COMPONENTS REMOVAL

(HIGH VOLTAGE CAPACITOR AND RECTIFIER AND SHORT PROTECTOR)

To remove the components, proceed as follows. Disconnect oven from power supply and remove the outer case. Discharge high voltage capacitor. Remove one (I ) screw holding capacitor holder to oven unit. Remove one (1) screw holding earth side terminal of rectifier, and remove capacitor holder.

5. Disconnect wire leads and terminal of rectifier from high voltage capacitor. Now, rectifier is free.

6. Disconnect terminals of short protector from high voltage capacitor.Now, capacitor is free.

CAUTION:

WHEN REPLACING RECTIFIER, EARTH SIDE TERMINAL MUST BE SECURED FIRMLY WITH A EARTHING SCREW.

POWER TRANSFORMER REMOVAL

Disconnect oven from power supply and remove outer case. Discharge high voltage capacitor. Disconnect wire leads from power transformer

4. Disconnect filament leads from magnetron and high voltage capacitor.

5. Remove two (2) screws holding transformer to unit chassis.

6. Remove power transformer.

MAGNETRON REMOVAL

Disconnect oven from power supply and remove outer case. Discharge high voltage capacitor. Disconnect wire leads from magnetron. Remove one (I ) screw holding air duct. Carefully loosen four (4) screws holding magnetron to waveguide flange. Lower magnetron assembly until tube is clear of the wavegu ide.

1. Re-install magnetron to waveguide flange by the four (4) mounting screws.

2. Install air duct to magnetron by one (1) mounting screw.

3. Re-connected wire leads to magnetron. CAUTION:

WHEN REPLACING THE MAGNETRON, BE SURE THE R.F. GASKET IS IN PLACE AND MAGNETRON MOUNTING

Re- install

SCREWS ARE TIGHTENED SECURELY.

Page 24

R -7280 R-l 720

UPPER/LOWER LATCH SWITCHES, MONITOR SWITCH

AND STOP SWITCH REMOVAL

1. Disconnect oven from power supply and remove

1. Re-install each switch in its place. Refer to Figure

outer case.

c-3.

2. Discharge high voltage capacitor.

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

3. Disconnect wire leads from switches.

4. Remove two (2) screws holding the latch hook from oven caity flange, and remove the latch hook.

5. To remove individual switch from the latch hook, push outward one (1) retaining tabs holding switch

in place.

Re- install

3 4

chapter “Pictorial Diagram”. Secure individual latch hook with two (2) mounting screws to oven cavity flange. Make sure that the monitor switch is operating properly. Refer to chapter “Test Procedure”, and the Adjustment procedure.

TURNTABLE MOTOR REMOVAL

Disconnect oven from power supply. Remove turntable motor cover by removing two (2)

screws.

Disconnect wire lead from turntable motor and remove two (2) screws holding turntable motor. Turntable motor is free now.

NOTE: This scrwu must be used the

specified 1cruw

(XFPSD40PlOOOO) as listed

on Parts Liet.

XFPSD40PlOOOO

Figure C-l.

( RDAl E04U)

TURNTABLE COUPLING REMOVAL

Remove turntable motor, refer to “Turntable Motor Removal”. Remove seal ring (O-ring). At this time turntable coupling will be free.

TURN TABLE

COUPLING

BOTTOM OVEN CAVITY

T.T. MOTOR

ANGLE

O-RING

Turntable Coupling

CONTROL PANEL ASSEMBLY REMOVAL

( RDAl E05U)

The complete control panel should be remove for re-

placement of the component.To remove control panel proceed as follows:

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

3. Disconnect wire reads from control panel components.

2. Discharge high voltage capacitor.

ward.

6. Now, individual components can be removed.

4. Remove one (1) screw holding the control panel

frame to oven cavity.

5. Left up the control panel assembly and pull it for-

Page 25

R-7280 R-l 720

UPPER/LOWER LATCH SWITCHES, MONITOR SWITCH AND

STOP SWITCH ADJUSTMENT

If the Upper and Lower latch switches, monitor and stop switch do not operate properly due to a mis-adjustment, the following adjustment should be made.

1. Loosen the two (2) screws holding the latch hook to the oven cavity front flange.

2. With the door closed, adjust the latch hook by moving it back and fon,vard, or up and down. In and out play

of the door allowed by the latch hook should be less than 0.5 mm.

Vertical adjustment of the latch hook is

not possible.

3. Secure the screws firmly.

4. Now, make sure of the latch switch operation. If the latch switch has not activated with the door closed, loose the two (2) screws holding the latch hook to the oven cavity front flange and adjust the latch hook position.

After the adjustment, make sure of the following points:

1. The in and out play of the door remains less than 0.5 mm at latched position.

2. The Upper and Lower latch switches interupt the circuit before the door can be opened.

3. The monitor switch contacts close when the door is

opened.

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

around the door with an approved microwave survey meter.

(Refer to Microwave Measurement Procedure.)

~ MONITOR

SWITCH

UPPER

’ LATCH

SWiTCH

LOWER LATCH SWITCH

STOP SWITCH

SWITCH

LEVER

OPEN

BUTTON

Latch Switches Adjustment

LATCH HEAD REMOVAL DOOR DISASSEMBLY

Remove the door assembly, refer to items 1 through 5 of “Door Replacement”.

Replacement of latch head are as follows:

1. Place the door assembly on a soft cloth with latches facing up.

3. Lift up the choke cover.

4. Now the choke cover is free from the door panel.

5. Remove the latch spring from the door panel.

6. Pushing up the latch head, it is now free from door panel.

2. Insert an iron plate (thickness of about 0.5mm) to the gap between the choke cover and the corner portion of door panel as shown figure to free the engagind parts.

FLAT TYPE SCREW.DRIVER

et-

PROTECT BY TAPE

Latch Head Removal and Door Disassembly

Page 26

R -7280 R-1720

DOOR REPLACEMENT AND ADJUSTMENT

DOOR REPLACEMENT

1. Disconnect the oven from the power supply and remove the

outer case.

2. Discharge the high voltage capacitor.

3. Remove the four (4) screws holding the upper and lower oven hinge to the oven cavity. The lower oven hinge is now free.

4. Remove the door assembly with upper oven hinge by pull It forward.

5. Separate the door assembly and upper oven hinge. The

door assembly IS now free.

6. Re-installing the upper oven hinge to the new door as-

sembly.

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

assembly with the four (4) mounting screws to the oven cavrty.

Make sure the door IS parallel with bottom Irne of the

oven face plate and the latch head pass through the latch holes correctly.

Note: After any service to the door, and approved mtcrowave

survey meter should be used to assure In compliance with proper microwave radiation standards.

(Refer to Mrcrowave Measurment Procedure.)

DOOR ADJUSTMENT When removing and/or loosening hinge such as in the case of i door replacement, the following adjustment criteria are taken.

Door is adjusted to meet the following three conditions by keeping screws of hinge loose.

1. Adjust door latch head at a position where they smoothly catch the latch hook through the latch hole. Refer to latch switch adjustment.

2. Deviation of the door alignment from the horizontal line of the cavity face plate is to be less than 1 .Omm.

3. The door is positioned with its face depressed toward the cavity face plate.

4. Reinstall the outer case and check the microwave leakage around the door with an approved microwave survey meter.

(Refer to Microwave Measurement Procedure.)

HINGE

OUTER CASE CABINET

Figure C-4. Door Assembly Replacement and Adjustment

Page 27

R-7280 R-1720

MICROWAVE MEASUREMENT

After- adjustment of door latch switches, monitor

switch and door are completed individually or coilectively, 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 more from external surface of the oven.

PREPARATION FOR TESTING: Before beginning the actual test for leakage, proceed

follows;

Make sure that the test instrument is operating normally as specific in its instruction booklet.

Important: Survey instruments that comply with the requirement for instrumentations as prescribed by the per-

formance standard for microwave ovens must be

used for testing.

32:

Recommended instruments are: NARDA 8100 NARDA 8200 HOLADAY HI 1500 SIMPSON 380M Place the oven tray into the oven cavity. Place the load of 275 fl5ml of water initially at

20 f5 “C in the center of the oven tray. The water container should be a low form of 600 ml beaker with inside diameter of approx. 8.5cm and made of an electrically non-conductive material such as glass or plastic. The placing of this standard load in the oven is important not only to protect the oven, but also to insure that any leakage is measured accurately. Close the door and turn the oven ON with the timer

set for several minutes. If the water begins to boil before the survey is completed, replace it with 275ml of the cool water. Move the probe slowly (not faster that 25cm/sec.)

along the gap. The microwave radiation emission should be measured at any point of 5cm or more from the external surface of the oven.

(RD81103U)

Page 28

R-7250 R-1720

at-

q-q $Cj g/-J

- n r

rtm D L

r6-Y

- ---- - --- --

r- UY In t m Pa;-

---‘- clilL-7

. -.

-----7.

r---e-

‘3n w z

v ‘5 2 g,

$iTg m’,

-.-.A

2 PIU cl/ u--AL.

-1

Page 29

R-7280 R-1720

,r‘-. . .

_ -

4H Y

;

Y :

: I

$8:

:&9 .a+8

;:g

__--

1 2 3 4 5 8

Page 30

R-7280 R-1720

CN-A

---------w--m--

Figure S-3. Printed Wiring Board

Page 31

R-7280

R-1720

PARTS LIST

Note : The voltage supplied to the parts ,,*I’ are greater than 250V.

f Refer to “REPLACEMENT PARTS LIST” described after PARTS LIST.

REF. NO.1

PART NO.

DESCRIPTION 1 CZ’TY 1 CODE

ELECTRICAL PARTS

I I I I I

’ (

l- 3 l- 4 l- 5 l- 6 l- 7 l- 8 l- 9 l-10 l-11 l-12 1-13 l-14

1-15 l-16 l-17

1-18

QACCAAOl 1 WREO

Mains supply cord

QSOCLAOOl WREO

Lamp socket

QFSHDAOO2WREO

Fuse holder

RR- WZAOO3WREO

Monitor resistor

0.8 f2

2ow

RTRN- Al 09WREO

T/C transformer

RC- QZAO34WREO

High voltage capacitor

RH- DZAOO8WREO

Rectifier

RH- DZAOl 2WRE0

Short protector

QFS- COO1 9WREO

Fuse M6.3A

RLMPTOO18WREO

Oven lamp

RMOTEA059WREO

Fan motor

RMOTDAO33WREO

Turntable motor

RV- MZAO34WREO

Magnetron

QSW- MAO1 5WREO

Stop switch (V-5330DK)

QSW- MAOO9WREO

Monitor switch (V-52200) QSW- MAOO7WREO RTRN- Al 07WREO

Upper latch switch and cook(lower latch) switch(V-5230D)

Power transformer QFS- TAOO4WREO

Temo. fuse

2- 3

2- 4 $1 ;

;: ; 2- 9

2-10 2-l 1 2-11A 2-12 2-13 2-14 2-15

GCABUAl OOWRPO

Outer case cabinet

TMAPCA277WRRO

Schematic diagram

GDAi - AO47WRWO

Unit chassis

GLEGPAOOGWREO

Foot

LSTPPOO65WRFO

Cord anchorage (upper) LSTPP0066WRFO Cord anchorage (lower) PCUSUO455WRPO

Shading cushion PSPAGQ002YBEO

Vibration proof cushion LBNDKAOl 5WRWIl

Capacitor holder PDUC- Al 34WRF0 Fan duct FFANJAOI 3WRK0

Fan blade LSTY- 003OWREO

Fan retainer clip PCAPH0030WREO Cabinet cap PHOK- AO22WRFO Latch hook MLEVPA065WRFO

Switch lever PCOVPAl 14WRE0

Capacitor cover

CABINET PARTS

fF Cl c2 c3 c4. c50, c92 c5

c20 c21, c93

c94 c90, c91 CF90 Dl 02 D50,DSO

D81 ,D84 Fl ICl

c2 c3

-1 51

CPWBFAO7OWRKO QCNCMA078DREO QPLGJ2255DREO QPLGJ2335DREO QCNCMA039DREO QCNCWA030DREO RV- KXAOOSDREC RC- QZ104SDREG RC- EZAl 30DREO RC- EZ337QDREO RC- KZl 03SDREO RC- EZ476QDREO RC- EZ225SDREO RC- KZA004DREO

RC- CZ221 SDREO RCRS- AOO-IDREO RSRCDA007DREO RH- DZAOl 1 DREO RH- DZA024DREO

QFS- AA005DREO RH- i ZA086DREO RH- i XA002DREO RH- i X241 3DRE0 RFi LNA002DREO RH- TZA008DREO

CONTROL PANEL PARTS

Control unit (R-7280/R-l 720) 4-pin connector (A) 3-pin connector (C) g-pin connector (D) 3-pin connector (F) 12-pin connector (G) Fluorescent display tube Capacitor 0.1 uF Capacitor 1000 uF Capacitor 330 uF Capacitor 0.01 uF Capacitor 47 uF Capacitor 2.2 uF Capacitor 0.015 uF

Capacitor 22OpF Ceramic filter KBR4OOB (400kHz)

Diode bridge (Sl WBAl 0) Diode (11 ES1 )

Diode (US1 OSOM)

5ov 5ov 25V 5ov 25V 5ov 25V

5ov

Fuse (ICP-Nl OS) LSI IC (AN79L12) IC (IX241 3) Filter coil (22 uH)

Transistor 2SA885 (Q. R)

1 1 1 4 1 1 1 1 1 1 1

: 1 1 1

1 1 1 1 1 1 1 1 1 3 1 1 3

1 1 1

1 1 1 1 1 1

AN AH AE AA AU AX AK AQ AE AN

AS BM AG

BP AG

AV AB

2; AA AA AA AA AD AG

2: AA AH AC AE

BS AC AC AE AB AE

AB AE AC AA AB AB AA

AB AF

AB AA

AE AM AC

Page 32

R -7280 R-1720

Note : The voltage supplied to the parts ‘I*” are greater than 250V.

jl Refer to “REPLACEMENT PARTS LIST” described after PARTS LIST.

4- 1 4- 1A 4- 18 4- 2 4- 3 4- 4 4- 5 4- 6 4- 7 4- 8

4- 8A 4- 9 4-70 4-11

4-12 4-13 4-14 4-l 5 4-16 4-17

5 5- 1 5- 2

5- 3

5- 4

6- 1 6- 2 6- 3 6- 4 6- 5

REF. NO.

PART NO.

DESCRIPTION

Q’TY

Et 080

Rl R2 R3 R4 R5 R12, R42 R13 R20, R21

R71 -R77 R30,R50 R41 R70 R78-81 R90 RYl ,RY2 SPl

VRSl ZDl ZD2 ZD20

3-2

RH- TZA042DREO RH- TZA049DREO RR- DZGR8NDREO RR- DZ102NDREO RR- SZ271 RDREO RR- Df821 NDREO RR- SZ821 RDREO RR- DZ203NDREO RR- DZl 23NDRE0 RR- DZl 03NDRE0

Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor

RR- DZ332NDREO RR- DZ473NDREO RR- DZA026DREO RR- DZ223NDREO RR- DZ105NDREO RRLY- 2102DRE0 RALM- A003DREO RH- VZAOl ODREO RH- EZA022DREO RH- EZ0009DREO RH- EZA029DREO DUNTKAl 65WRK0 DUNTKAl77WRKO HPNLCA334WRFO JBTN- A273WRFO MSPRDA003WREO PTPEHA020WREO XHPSD30Pl 2XS0

Transistor DTA143E Transistor DTC114E

6.8 n 1kQ

270 Q 820 Q 820 f-2 20k Q

12kR 10k R

3.3k Q 47k Q

(150k Q x 4)

22k Q

1MQ Relay (VSlgMBU-NR) Buzzer (PS3025PO2)

Varistor (156471 K-T) Zener diode (HZ20-3) Zener diode (HZ6C-2) Zener diode (HZ9A-3)

Key unit (R-7280) Key unit (R-l 720) Control panel frame

Open button

Button spring Control panel tape Screw; Control unit mtg.

Resistor Resistor Resistor block Resistor Resistor

3- 3 3- 4 3- 5 3- 6 3- 7

1/4w 1/4w

1/4w

1w 1/4w 1/4w 1/4w

1/4w 1/4w

1 1 1 1

: A 2

4 :

1 1 1 1 1 1 1 1 1 1 1

DOVN- A091 WRTO LANGFAO54WRWO LANGFA053WRPO PPACGAOl 7WRE0 PCUSUA081 WRPO GCOVHAO75WRWO MHNG- AO73WRMO FHNG- A041 WRMO NTNT- AOO7WREO FROLPAOl OWRKO NROLPAOl 2WRE0 NCPL- A01 5WRFO PFi LWA021 WRPO PCOVPAOSOWREO PCLi COO26WREO PDUC- Al 33WRF0 GFTA- AOO5WRWO PCUSUAO52WRPO LANGTAl4OWRWO PCUSG0245WRPO

OVEN PARTS

Oven cavity Chassis support Oven supporting plate O-ring Cushion

Turntable motor cover

Upper over hinge

Lower oven hinge Turntable tray Turntable roller assembly Turntable roller Turntable couplrng

Oven lamp filter Waveguide cover

Clip Steam duct Oven lamp access cover

Cushion Oven supporting angle Cushion

1 1 1 1 1 1 1

DOOR PARTS

CDORFA224WRKO CDORFAl64WRKO LSTPPA028WRFO LSTPPA034WRFO MSPRTAO52WREO DDORFAl 58WRY0

DDORFAl 26WRY0 GCOVHA074WRFO GCOVHA082WRFO

Door assembly, complete (R-7280)

Door assembly, complete ( R - 1720)

Latch head (R-7280)

Latch head (R-1720)

Latch spring

Door panel (R-7280)

Door panel (R-1720)

Choke cover (R-7280)

Choke cover ( R- 1720)

MISCELLANEOUS

QW- QZAO29WREO QW- QZAO3OWREO

High voltage wire A

FW- VZA362WREO

High voltage wire B Main wire harness

TCAUHOl 14WRRO

Caution label TSPCNA771 WRRO TSPCNA770WRRO

Name plate (R-7280)

Name plate (R-1720)

CODE

AB AB AA AA AA AA AA AA AA AA

Pi:: AA AA AA AL AF AE AA AA AA AY AX AK AE AA AA AA

BL AD AE AB AA AF AD AF AS AH AC AD AB AEAAAK AC AA

Page 33

R-7280 R-l 720

Note : The voltage supplied to the parts n*n are greater than 250V.

* Refer to “REPLACEMENT PARTS LIST” described after PARTS LIST.

REF. NO.

PART NO.

DESCRIPTION Q’TY CODE

6- 6

T i N S - A0 3 3 WR R 0 Operation manual (R-7280)

Ti NS- AO39WRRO

Operation manual (R-l 720) 1 AE

6- 7

FW-VZA361 WREO

Latch switch harness 1 AU

;: ;

QTANP0020YBEO

Connector CE-230 1

TLABSOO57WRRO

Fuse label 1

6-10 TCADCO253WRRO

Cook book

6-l 1

FW- VZA363WREO Stopswitch harness : AF

7- 1 7- 2 7- 3

7- 4 7- 5

7- 6 7- 7 7- 8 7- 9 7-10 7-l 1 7-12 7-13 7-14 7-l 5 7-16

‘SCREWS, NUTS AND WASHERS

L X - B Z A 0 3 6 WR E 0 Screw: outer case cabinet mtg.

XFPSD40Pl 0000 Screw:

magnetron and turntable motor cover mtg.

XHTSD40P08RVO Screw:

lamp access cover, capacitor holder, T/C transformer and monitor resistor mtg.

XOTSD40Pl 2RV0 Screw:

unit chassis, upper and lower hinge and oven supporting angle mtg.

XTTSD40Pl2000 Screw;

control panel and for motor ass’y mtg.

LX- EZAOO4WREO Screw;

latch hook mtg. XFPSD30P08XOO Screw: lampsocketmtg. XFPSD40P08000 Screw;

turntable motor mtg. X B P S D4 0 P 2 5 0 0 0 Screw; fan motor mtg. XBPSDSOPl OKSO Screw:

power transfamer mtg. XFPSD40P08KOO Screw:

earth and rectifier mtg and T/C grounding X F P S D4 0 P 2 0 0 0 0 Screw: cord anchorage mttg. X WA/S 05 0 - 0 6 0 0 0 Washer: power transformer mtg. XNESD40- 32000 Nut:

fan motor mtg. XFPSD30Pl 0000 Screw; fuseholdermtg.

LX- BZO206WREO Screw:

outer case cabinet

AA ii AA 4 AA

AA z AA 1

AA 22

AA 2

3 AA 1 AA

AA : AA

HOW TO ORDER REPLACEMENT PARTS

To have your order filled promptly and correctly, please furnish the following information.

1. MODEL NUMBER

2. REF. NO.

3. PART NO.

4. DESCRIPTION

(RDP1303U)

Page 34

R -7280 R-l 720

REPLACEMENT PARTS LIST

This replacement parts list shows interchangeability of marked ( * ) parts on the control panel parts to the alterations of product locations. This list has been prepared to show LISTED PART NO. along with the USED PART NO. side by side.

(RDQ1101 U\

IREF. NO. LISTED PART NO. I Cl

RC- QZl 04SDRE0

,RC- EZAl 30DRE0

C4 etc.

JRC- EZ337QDREO

RC- KZl 03SDRE0

C5 etc.

RC- EZ476QDREO

c20 RC- EZ225SDREO

USED PART NO.

VCQYCUl HMl 04K VCEAAHl HM108M VCEAAAl EM337M VCKZPUl HFl 032 VCEAAAl EW476M VCEAAUl HW225M

REF. NO.

C21 etc. C90 etc. Dl D2 etc.

EO Q30 etc.

LISTED PART NO.

RC- KZA004DREO

RC- CZ221 SDREO RSRCDA007 DREO RH- DZAOl 1 DREO RH- TZA008DREO RH- TZA042DREO RH- TZA049 DREO

USED PART NO.

VCKYATI EXl 53N VCCCPRl H3221 J RH- DX2006YAZZ VHDllESl///-1 VS2SA885- Q/ - 1 VSDTA- 143- A- 1 VSDTC- 114- A- 1

NOTE : Common resistors have been omited from this patrs list, such as 1/4W and 1/2W carbon resistors below is a compatibility list and cross referrence information.

PART CODE LISTED

RR-DZIOSNDREO

B / RR-DZ102yDREO

I . .

C 1 RR- YZl 01 rDRE0

1 2

PART CODE COMPATIBLE

DESCRIPTION

VRD-ST2DF103J

I 1/4W 10k Q small shape carbon film

, I

VRD-ST2EF102J

j 1/4W 1 .Ok Q carbon film. /

VRD-ST2HAlOl J

1 1

/ 1/2W 100 Q carbon film.

3 4

PART CODE LISTED ‘1.0: Carbon film resistor. ‘2.N : 1/4W and small shape.

0: I /4w. P:

1/2w.

l 3.D : Carbon film resistor.

“4.0 :

1/4W and small shape. E: 1/4w. H:

1/2w.

(RDQ1102U)

Page 35

R-7280 R-l 720

1 2

r I

I 4 5 8

OVEN PARTS

4-5

4-10

I-

--w- ---------- - ----- ~

I I

f I

4 t

------------

-------

Page 36

R -7280 R-1720

I 4 5

l-9

fu?3

2 I

Page 37

CONTROL PANEL PARTS

R-7280 R-1720

I 4

3-3

\ i

DOOR PARTS

,/‘\,

MISCELLANEOUS

i~,-gC

I-

I 5 / 6

Page 38

I /

-j

‘1

PACKING AND ACCESSORIES

* TURNTABLE TRAY

TURNTABLE SUPPORT

- OPERATION

MANUAL & SHEET

COOK BOOKLET

DOOR PROTECTION SHEET

PACKING ADO KIT

SHRINK FILM SHEET

TRAYHOLDER

x (SPADFA049WREO)

ACCESSORIES ASSENBLY

* Not Replaceable Items

3 4

Page 39

R-7280 R-1720

Page 40