Sharp R3C59 Schematic

Info Display

HELP

CONVENIENCE MEALS

Pasta Meal

Frozen Dinner

REHEAT MENU

DINNER

CASSEROLE

PLATE

PIZZA

BEVERAGE

VEGETABLES

RICE

MEAT

EASY DEFROST

12345

6789

LESS

POWER LEVEL

TIMER

CLOCK

AUTO START

STOP

INSTANT COOK

CLEAR

START

R-3C59

SER VICE MANUAL

SX612R3C59PJ/

MICROWAVE OVEN

SOUP

PIE

PASTA



MODEL

R-3C59

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

TABLE OF CONTENTS

Page

CAUTION, MICROWAVE RADIATION ............................................................................................................ 1

WARNING..........................................................................................................................................................1

PRODUCT SPECIFICATIONS......................................................................................................................... 2

GENERAL INFORMATION ............................................................................................................................... 2

APPEARANCE VIEW....................................................................................................................................... 3

OPERATION SEQUENCE ............................................................................................................................... 4

FUNCTION OF IMPORTANT COMPONENTS ................................................................................................ 5

SERVICING ...................................................................................................................................................... 7

TEST PROCEDURE ........................................................................................................................................ 9

TOUCH CONTROL PANEL ............................................................................................................................ 15

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE........................................................... 19

MICROWAVE MEASUREMENT .................................................................................................................... 24

WIRING DIAGRAM ........................................................................................................................................ 25

PICTORIAL DIAGRAM................................................................................................................................... 26

CONTROL PANEL CIRCUIT .......................................................................................................................... 27

PRINTED WIRING BOARD ............................................................................................................................ 28

PARTS LIST.................................................................................................................................................... 29

SHARP CORPORATION

R-3C59

SERVICE MANUAL

MICROWAVE OVEN

R-3C59

PRODUCT SPECIFICATIONS

R-3C59

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, so they will be qualified to render satisfactory customer service.

CAUTION

MICROWAVE RADIATION

DO NOT BECOME EXPOSED TO RADIATION FROM THE MICROWAVE GENERATOR OR OTHER PARTS CONDUCTING MICROWAVE ENERGY.

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.

APPEARANCE VIEW

OPERATING SEQUENCE

FUNCTION OF IMPORTANT COMPONENTS

SERVICING AND TROUBLESHOOTING CHART

TEST PROCEDURE

TOUCH CONTROL PANEL ASSEMBLY

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 "*" on parts list are used at voltages more than 250V.

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

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

SHARP CORPORATION

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

MICROWAVE MEASUREMENT

WIRING DIAGRAM

PARTS LIST

OSAKA, JAPAN

R-3C59

PRODUCT SPECIFICATIONS

ITEM DESCRIPTION

Power Requirements 230 - 240 Volts

50 Hertz

Single phase, 3 wire earthed Power Consumption 1.5kW Power Output 1000 watts nominal of RF microwave energy (IEC 705)

Operating fequency 2450 MHz

Case Dimensions Width 520 mm

Height 302 mm including foot

Depth 403 mm Cooking Cavity Dimensions Width 348 mm

Height 216.5 mm

Depth 379 mm Turntable diameter 335mm Control Complement Touch Control System

Clock ( 1:00 - 12:59)

Timer (0 - 99 minutes 99 seconds)

Microwave Power for Variable Cooking

Repetition Rate;

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

MEDIUM HIGH ..................................................approx. 70% of Full Power

MEDIUM .............................................................approx. 50% of Full Power

MEDIUM LOW .................................................... approx. 30% of Full Power

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

HELP pad

CONVENIENCE MEALS pads

REHEAT MENU pads

INFORMATION COOK pads

NUMBER pads

POWER LEVEL pad

MORE, LESS pads

TIMER pad

CLOCK pad

AUTO START pad

STOP/CLEAR pad

INSTANT COOK/START pad Set Weight Approx. 17 kg

GENERAL INFORMATION

WARNING

THIS APPLIANCE MUST BE EARTHED

IMPOTANT

THE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE:

GREEN-AND-YELLOW : EARTH BLUE : NEUTRAL BROWN : LIVE

1. Ventilation openings

11 13

Info Display

HELP

CONVENIENCE MEALS

REHEAT MENU

Pasta Meal

Frozen Dinner

DINNER

PLATE

CASSEROLE

SOUP

PIEPIZZA

BEVERAGE

VEGETABLES

RICE / PASTA

MEAT

LESS

TIMER

STOP

CLEAR

INSTANT COOK



START

CLOCK

AUTO START

POWER LEVEL

EASY DEFROST

12 34 5

67 89

CONVENIENCE MEALS PADS Press to select Convenience Meals menu.    NUMBER PADS Press to enter cooking times, clock time, weight or quantity of food.  

MORE ( ), LESS ( ) PADS

 Press to increase/decrease the time in one minute increments during cooking or to alter the doneness for the Convenience Meals or Information Cook modes. 

CLOCK PAD Press to set Clock 

TIMER PAD Press to set Timer.



 STOP/CLEAR PAD

Press to clear during programming. Press once to stop operation of oven during cooking; press twice to cancel cooking programme.

HELP PAD Press to select information guide on and off, child lock or demonstration mode. Press to display preset menu cooking information.   PEHEAT MENU PADS Press to select Reheat Menu.

    INFORMATION COOK PADS Press to select Information Cook mode.  

POWER LEVEL PAD Press to select microwave power setting. If not pressed, HIGH is automatically selected.     AUTO START PAD Press to set Auto Start time.   INSTANT COOK/START PAD Press to start oven after setting programmes. Press once to cook for 1 minute on HIGH or increase in 1 minute increments each time this pad is pressed during cooking.

COOK KG DEF HELP

Indicator

Display

2. Oven lamp

3. Door hinges

4. Door safety latches

5. See through door

6. Door seals and sealing surfaces

7. Coupling

8. Door open button

9. Touch control panel

10.Digital readout

11.Wave guide cover

12.Power supply cord

13.Rating label

14.Turntable tray

15.Turntable support

R-3C59

APPEARANCE VIEW

TOUCH CONTROL PANEL

R-3C59

OPERATION SEQUENCE

OFF CONDITION

Closing the door activates all door interlock switches (1st. latch switch, 2nd. latch switch and stop switch).

IMPORTANT When the oven door is closed, the monitor switch contacts (COM-NC) must be open. When the microwave oven is plugged in a wall outlet, rated voltage is supplied to the point A3+A5 in the control unit.

Figure O-1 on page 25

1. The display shows SHARP , MICRO- , WAVE and OVEN .

2. To set any programmes or set the clock, you must first touch the STOP/CLEAR pad.

3. : appears in the display.

NOTE: When the oven door is opened, the oven lamp

comes on at this time.

MICROWAVE COOKING CONDITION

HIGH COOKING

Enter a desired cooking time with the touching NUMBER pad and start the oven with touching START pad.

Function sequence

Figure O-2 on page 25

CONNECTED COMPONENTS RELAY Oven lamp, Fan motor, Turntable motor RY1 Power transformer RY2

1. Rated voltage is supplied to the primary winding of the power transformer. The voltage is converted to about

3.3 volts A.C. output on the filament winding and high voltage of approximately 2000 volts A.C. on the secondary winding.

2. The filament winding voltage (3.3 volts) heats the magnetron filament and the high voltage (2000 volts) is sent to the voltage doubling circuit, where it is doubled to negative voltage of approximately 4000 volts D.C..

3. The 2450 MHz microwave energy produced in the magnetron generates a wave length of 12.24 cm. This energy is channeled through the waveguide (transport channel) into the oven cavity, where the food is placed to be cooked.

4. When the cooking time is up, a signal tone is heard and the relays RY1+RY2 go back to their home position. The circuits to the oven lamp, power transformer, fan motor and turntable motor are cut off.

5. When the door is opened during a cook cycle, the switches come to the following condition

CONDITION

SWITCH CONTACT COOKING 1st. latch switch COM-NO Closed Open 2nd. latch switch COM-NO Closed Open Monitor switch COM-NC Open Closed Stop switch COM-NO Closed Open

DURING DOOR OPEN

(NO COOKING)

The circuits to the power transformer, fan motor and turntable motor are cut off when the 1st. latch switch, 2nd. latch switch, and stop switch are made open. The oven lamp remains on even if the oven door is opened after the cooking cycle has been interrupted, because the relay RY1 stays closed. Shown in the display is the remaining time.

6. MONITOR SWITCH CIRCUIT The monitor switch is mechanically controlled by oven door, and monitors the operation of the 1st and 2nd. latch switches.

6-1 When the oven door is opened during or after the

cycle of a cooking program, the 1st. latch switch, 2nd. latch switch and stop switch must open their contacts first. After that the contacts (COM-NC) of the monitor switch can be closed.

6-2. When the oven door is closed, the contacts (COM-

NC) of the monitor switch must be opened. After that the contacts of the 1st. latch switch, 2nd. latch switch and stop switch are closed.

6-3. When the oven door is opened and the contacts of

the1st. latch switch, 2nd. latch switch remain closed. The fuse M8A will blow, because the monitor switch is closed and a short circuit is caused.

MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW COOKING

When the microwave oven is preset for variable cooking power, 230-240 volts A.C. power is supplied to the power transformer intermittently within a 32-second time base through the relay contact which is coupled with the current-limiting relay. The following levels of microwave power are given.

SETTING;

32 sec. ON

HIGH

24 sec. ON

MEDIUM HIGH

18 sec. ON

MEDIUM

12 sec. ON

MEDIUM LOW

6 sec. ON

LOW

NOTE: The ON/OFF time ratio does not exactly correspond

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

8 sec. OFF

Approx. 70%

14 sec. OFF

Approx. 50%

20 sec. OFF

Approx. 30%

26 sec. OFF

Approx. 10%

FUNCTION OF IMPORTANT COMPONENTS

R-3C59

DOOR OPEN MECHANISM

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

Door

Latch Hook 

Latch Heads

Switch Lever

Stop  Switch

2nd. Latch Switch

Monitor  Switch

1st. Latch  Switch

Figure D-1. Door Open Mechanism

1ST. LATCH SWITCH, 2ND. LATCH SWITCH AND STOP SWITCH

1. When the oven door is closed, the contacts COM-NO) must be closed.

2. When the oven door is opened, the contacts .(COMNO) must be opened.

MONITOR SWITCH

1. When the oven door is closed, the contacts (COM-NC) must be opened.

2. When the oven door is opened, the contacts (COMNC) must be closed.

3. If the oven door is opened and the contacts (COM-NO) of the 1st. latch switch and 2nd. latch switch fail to open, the fuse M8A blows simultaneously with closing the contacts (COM-NC) of the monitor switch.

CAUTION: BEFORE REPLACING A BLOWN FUSE M8A

TEST THE 1ST. LATCH SWITCH, 2ND. LATCH SWITCH MONITOR SWITCH AND MONITOR RESISTOR FOR PROPER OPERATION.

MONITOR RESISTOR R 0.8Ω 20W

The monitor resistor prevents the fuse M8A bursting when the fuse M8A blows due to the operation of the monitor switch.

ASYMMETRIC RECTIFIER

The asymmetric rectifier is a solid state device that prevents current flow in both directions. And it prevents the temperature rise of the power transformer by blowing the fuse M8A when the high voltage rectifier is shorted.

The rated peak reverse voltage of D1 of the asymmetric rectifier is 6 KV The rated peak reverse voltage of D2 of the asymmetric rectifier is 1.7 KV. D1 and D2 of the asymmetric rectifier or high voltage rectifier are shorted when the each peak reverse voltage goes beyond the each rated peak reverse voltage. (The process of blowing the fuse M8A.)

1. The high voltage rectifier is shorted by any causes when microwave cooking.

2. The peak reverse voltage of D2 of the rectifier goes beyond the rated peak reverse voltage 1.7 KV in the voltage doubler circuit.

3. D2 of the rectifier is shorted.

4. The large electric currents flow through the high voltage winding of the power transformer.

5. The large electric currents beyond 8A flow through the primary winding of the power transformer.

6. The fuse M8A blows by the large electric currents.

7. The power supply to all the electrical parts are cut off.

FUSE M8A

1. The fuse M8A blows when the contacts (COM-NO) of the 1st. latch switch and 2nd. latch switch remain closed with the oven door open and when the monitor switch closes.

2. The fuse M8A also blows when asymmetric rectifier, H.V. rectifier, H.V. wire harness, H.V.capacitor, magnetron or secondary winding of power transformer is shorted.

3. If the wire harness or electrical components are shortcircuited, this fuse M8A blows to prevent an electric shock or fire hazard.

OVEN THERMAL CUT-OUT

The thermal cut-out, located on the top of the oven cavity, is designed to prevent damage to the oven by fire. If the foods load is overcooked, by either error in cook time or defect in the control unit, the thermal cut-out will open. Under normal operation, the oven thermal cut-out remains closed. However, when abnormally high temperatures are reached within the oven cavity, the oven thermal cut-out will open at 125˚C, causing the oven to shut down. The defective thermal cut-out must be replaced with new one.

MAGNETRON THERMAL CUT-OUT

The thermal cut-out located near the magnetron is designed to prevent damage to the magnetron if an over heated condition develops in the tube due to cooling fan failure, obstructed air guide, dirty or blocked air intake, etc. Under normal operation, the thermal cut-out remains closed. However, when abnormally high temperatures are reached within the magnetron, the thermal cut-out will open at 95˚C causing the oven to shut down, when the magnetron has cooled to 75˚C, the thermal cut-out closes and cook cycle will resume.

D2 D1

ASYMMETRIC RECTIFIER

HIGH VOLTAGE  RECTIFIER

TURNTABLE MOTOR

The turntable motor drives the turntable roller assembly to rotate the turntable.

R-3C59

FAN MOTOR

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

NOISE FILTER

The noise filter prevents the radio frequency interference that might flow back in the power circuit.

R-3C59

SERVICING

WARNING TO SERVICE PERSONNEL

Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts of the high voltage circuit will result in electrocution. High voltage capacitor, Power transformer, Magnetron, High voltage rectifier assembly, High voltage harness.

REMEMBER TO CHECK 3D

1) Disconnect the supply.

2) Door opened, and 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 insulated screwdriver.

Sharp recommend that wherever possible fault-finding is carried out with the supply disconnected. 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 3D checks and reexamine 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 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 because

of a blown fuse M8A in the 1st. latch switch

- 2nd. latch switch - monitor switch - monitor resistor circuit, check the 1st. latch switch, 2nd. latch switch, monitor switch and monitor resistor before replacing the fuse M8A.

R-3C59

CK = Check / RE = Replace

CONDITION

OFF CONDITION

ON CONDITION

TEST PROCEDURE

POSSIBLE CAUSE

AND

DEFECTIVE PARTS

PROBLEM

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

FUSE M8A blows when power supply cord is plugged into wall outlet.

Display does not show anything when power supply cord is plugged into wall outlet.

Display does not operate properly when STOP/CLEAR pad is touched.

Oven lamp does not light at door opened. (Display appears.)

Oven does not start when the START pad is touched. (Display appears)

Oven lamp does not light (Display appears.)

Fan motor does not operate. (Display appears.)

Turntable motor assembly does not operate. (Display appears.)

Oven or any electrical parts does not stop when cooking time is 0 or STOP/CLEAR pad is touched.

Oven seems to be operating but little or no heat is produced in oven load. (Microwave power level is set at HIGH)

Oven does not seems to be operating properly when MEDIUM HIGH, MEDIUM, MEDIUM LOW or LOW is set. (Oven operates properly at HIGH and then the STOP/ CLEAR pad is touched the oven stops.)

Oven goes into cook cycle but shuts down before end of cooking cycle.

Oven stops as soon as when the START pad is touched.

ABCDEEEEGFH HI KLMN RECKCKRE CK CKCKCK CK J

MAGNETRON

POWER TRANSFORMER

H.V. RECTIFIER ASSEMBLY

HIGH VOLTAGE CAPACITOR

1ST. LATCH SWITCH

2ND. LATCH SWITCH

STOP SWITCH

MONITOR SWITCH

MONITOR RESISTOR

THERMAL CUT-OUT 95˚C /125˚C

FAN MOTOR

TURNTABLE MOTOR

FUSE M8A

TOUCH CONTROL PANEL

KEY UNIT

RELAY (RY-1, RY-2)

FOIL PATERN ON P.W.B.

POWER SUPPLY CORD

SHORTED WIRE HARNESS

OPENED WIRE HARNESS

OVEN LAMP OR SOCKET

WALL OUTLET

MISADJUSTMENT SWITCH

HOME FUSE OR BREAKER

BLOCKED COOLING FAN

BLOCKED VENTILATION

NOISE FILTER

TEST PROCEDURES

R-3C59

PROCEDURE

LETTER

A MAGNETRON TEST

NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL WHILE THE OVEN IS IN OPERATION.

CARRY OUT 3D CHECK. Isolate the magnetron from high voltage circuit by removing all leads connected to 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 short 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 replaced.

MICROWAVE OUTPUT POWER (1 Litre water load)

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/4.187 calorie is generated. On the other hand, if the temperature of the water with V(ml) rises ∆T (°C) during this microwave heating period, the calorie of the water is V x ∆T.

COMPONENT TEST

The formula is as follows;

P x t / 4.187 = V x ∆ T P (W) = 4.187 x V x ∆T / t

Our condition for 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.......42 sec.

P = 100 x ∆T

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 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 at minimum and accurate thermometer.

7. The water load must be (1000±5) g.

8. “t” is measured while the microwave generator is operating at full power. Magnetron filament heatup time is not included.

NOTE: The operation time of the microwave oven is “t + 2” sec. 2 sec. is magnetron filament heat-up time.

Measuring method:

1. Measure the initial temperature of the water before the water is added to the vessel. (Example: The initial temperature T1 = 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 ∆ 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 P in watts from above formula.

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