Sharp R211M-003 Schematic

SERVICE MANUAL

COOKING CONTROL

WITH COOK & DEFROST GUIDE

S1892R211M///

ILLUMINATED

TIMER

2.0

7 8

0.7

1.0

(KG)

R-211

MICROWAVE OVEN

MODEL

R-211(W)/(BL)M R-211(G)M R-211(B)M

In the 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

SERVICING ...................................................................................................................................... 2

CAUTION, MICROWAVE RADIATION............................................................................................. 3

WARNING......................................................................................................................................... 3

PRODUCT DESCRIPTION............................................................................................................... 3

OPERATING SEQUENCE................................................................................................................ 4

DOOR SWITCHES ........................................................................................................................... 4

OUTPUT POWER TEST PROCEDURE........................................................................................... 5

TEST PROCEDURES....................................................................................................................... 6

DIGITAL ANALOGUE CONTROL PANEL ASSEMBLY ................................................................... 8

COMPONENT REPLACEMENT....................................................................................................... 12

SCHEMATIC DIAGRAM ................................................................................................................... 13

WIRING DIAGRAM ........................................................................................................................... 14

PARTS LIST...................................................................................................................................... 17

EXPLODED ILLUSTRATION............................................................................................................ 20

SHARP CORPORATION

211M -

SERVICING

WARNING TO SERVICE PERSONNEL

Microwave ovens contain circuitry capable of producing very high voltage and current. Contact with following parts will result in electrocution:High voltage capacitor, High voltage transformer, Magnetron, High voltage rectifier, 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 using a screwdriver with an insulated handle.

Sharp recommend that wherever possible, fault-finding is carried out with the supply disconnected. In some cases, it may be necessary to connect the supply with the cover removed to carry out fault investigation in the control circuitry. In such cases, the high voltage circuit should be disabled as described below to reduce the hazards:-

• Carry out 3D checks (see above).

• Disconnect the supply leads from the high voltage transformer, making a note of the polarity. Insulate the connectors, ensuring they are positioned away from the transformer and fastened there.

• Connect any relevant test equipment e.g. voltmeter.

• Reconnect the oven to the supply, then close the door.

• Note the results of the test, taking care to keep clear of the operational oven.

• Carry out 3D checks (see above).

• Reconnect the leads to the transformer. Take care to observe correct polarity.

• Carry out 4R checks (see below).

Microwave ovens should not be used without a load. 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 one (1) minute, set the power level to HIGH (100%) and push the start key. When the one (1) minute has elapsed (timer at zero) carefully check that the water is now hot.

AFTER REPAIR 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.

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.

IMPORTANT: If the oven becomes inoperative because of a blown fuse F8A in the 1st latch switch - monitor switch

circuit, check the 1st latch switch and monitor switch before replacing the fuse F1.

211M -

CAUTION / WARNING

CAUTION

MICROWAVE RADIATION

Do not become exposed to radiation from the magnetron or other parts conducting microwave energy. 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.

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

The parts marked '*' on the parts list and schematic diagram have voltages in excess of 250V.

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

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

WARNING

THIS APPLIANCE MUST BE EARTHED. THE WIRES IN THIS MAINS LEAD ARE COLOURED IN

ACCORDANCE WITH THE FOLLOWING CODE: GREEN-AND-YELLOW : EARTH BLUE : NEUTRAL BROWN : LIVE

If the mains lead is replaced, only part number QACCBA030WRE2 should be used

PRODUCT DESCRIPTION

SPECIFICATION

Power Requirements 230-240 Volts 50 Hertz Single phase, 3 wire grounded Power Consumption 1.24kW Power Output 800 watts nominal of RF microwave energy (measured by way of IEC 705)

Operating frequency of 2450 MHz Case Dimensions Width 449 mm Height 282 mm including foot Depth 369 mm Cooking Cavity Dimensions Width 290 mm Height 194 mm Depth 313 mm Turntable diameter 272 mm Control Complement DIGI/ANA

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

Set Weight Approx. 13.3 kg

211M -

OPERATING SEQUENCE

OFF CONDITION

Closing the door activates all door interlock switches (monitored latch switch and latch switch).

IMPORTANT When the timer knob is at "0" the oven is in the OFF condition.

HIGH, MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW COOKING

When the microwave oven is preset for variable cooking power, the line voltage is supplied to the power transformer intermittently within a 26-second time base through the relay contact which is coupled with the current-limiting relay (RY2). The following levels of microwave power are given. SETTING

26 sec. ON

HIGH

20 sec. ON

MEDIUM HIGH

14 sec. ON

MEDIUM

8 sec. ON

MEDIUM LOW

4 sec. ON

LOW

6 sec. OFF

12 sec. OFF

18 sec. OFF

22 sec. OFF

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

to the percentage of microwave power, because approx. 3 seconds are needed for heating up the magnetron filament.

Approx. 100% = 800 Watts

Approx. 70% = 560 Watts

Approx. 50% = 400 Watts

Approx. 30% = 240 Watts

Approx. 10% = 80 Watts

DOOR SWITCHES

DOOR OPEN MECHANISM

LATCH HOOK

DOOR

LATCH HEADS

DOOR OPEN BUTTON

SW2: MONITOR SWITCH

SW1: MONITORED LATCH SWITCH

SW3: STOP SWITCH

OPEN LEVER

MONITORED LATCH SWITCH (SW1) STOP SWITCH (SW3)

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

2. When the oven door is opened, the contacts (COM NO) must be opened.

MONITOR SWITCH (SW2)

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

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

3. If the oven door is opened and the contacts (COM - NO) of the monitored latch switch (SW1) fail to open, the fuse F8A blows simultaneously with closing the contacts (COM - NC) of the monitor switch (SW2).

CAUTION: BEFORE REPLACING A BLOWN FUSE (F1)

TEST THE MONITORED LATCH SWITCH (SW1), + MONITOR SWITCH (SW2) FOR PROPER OPERATION.

Figure D-1. Door Open Mechanism

211M -

OUTPUT POWER TEST PROCEDURE

MICROWAVE OUTPUT POWER (IEC-705) The power output of this oven is rated using the method specified by IEC-705. Full details of how to carry out this

procedure can be found in the Sharp Technical Training notes which is available from Sharp Parts Centre (part number SERV-LITMW01).

Using this procedure, the heating time to raise 1000g of water by 10°C is approximately 50 seconds. The IEC-705 procedure must be carried out using laboratory-type procedures and equipment. These requirements

make the procedure unsuitable for routing performance checks. An indication of the power being produced by the oven can however be obtained using the procedure given below.

Alternative simplified method:

1. Place 2 litres of cold water (between 12°C and 20°C) in a suitable container.

2. Stir the water and measure the temperature in °C. Note temperature as T1.

3. Place the container in the microwave and heat the water for 2 minutes on full power.

4. When the 2 minutes is completed, remove the container and stir the water. Note the water temperature as T2.

5. Calculate the output power using the following formula: R.F. Power Output = (T2 - T1) x 70.

Note: The result from this test should be within 10% of the power rating stated on the rating label.

MICROWAVE LEAKAGE TEST This oven should be tested for microwave leakage on completion of any repair or adjustment, following the procedure

described in the Sharp Technical Training notes (part number SERV-LITMW01). The maximum leakage permitted in BS EN 60335-2-25 is 50W/m

(equivalent to 5mW/cm2), however it is not normal to detect any significant leakage,

therefore, any leakage which is detected should be investigated. It is essential that only leakage detectors with current calibration traceable to the National Physical Laboratories are used. Suitable leakage detectors : CELTEC A100

APOLLO X1

211M -

TEST PROCEDURES

COMPONENT TEST

CONTROL PANEL ASSEMBLY TEST

The control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike conventional microwave ovens, proper maintenance can not be performed with only a voltmeter and ohmmeter. In this service manual, troubleshooting by replacement is described according to the symptoms indicated.

1. Control Panel The following symptoms indicate a defective control unit.

1-1 In connection with LEDs

a) At a certain LED, all or some LEDs do not light up. b) At a certain LED, brightness is low. c) Only one LED does not light up. d) All or some LEDs continue to light up. e) A certain group of LEDs do not light up. f) The LEDs flicker.

1-2 Other possible troubles caused by defective control unit.

a) Buzzer does not sound or continues to sound. b) Cooking is not possible. c) Cooking time can not be set. d) Power level can not be set.

RELAY TEST

CARRY OUT

3D CHECKS.

Remove the outer case and check voltage between Pin Nos. 3 and 5 of the 3 pin connector (A) on the control unit with an A.C. voltmeter. The meter should indicate 230-240 volts, if not check oven circuit.

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

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

DC. voltage not indicated....... Check diode which is connected to the relay coil. If diode is good, control unit is defective.

RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS

RY1 Approx. 12.0V D.C. Oven lamp / Turntable motor / Fan motor RY2 Approx. 12.0V D.C. High voltage transformer

CARRY OUT 4R CHECKS.

211M -

TEST PROCEDURES

COMPONENT TEST 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 input circuit on the PWB, this foil pattern acts as a fuse. If the foil pattern is open, follow the troubleshooting guide given below for repair. Problem: POWER ON, indicator does not light up.

CARRY OUT

STEPS OCCURRENCE CAUSE OR CORRECTION

1 The rated AC voltage is not present at Check supply voltage and oven power cord.

2 The rated AC voltage is present at primary Low voltage transformer or secondary circuit defective.

3 Only pattern at "a" is broken. *Insert jumper wire J1 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 a

3D CHECKS.

Power terminal of CPU connector (CN-A).

side of low voltage transformer. Check and repair.

(CARRY OUT 3D CHECKS BEFORE REPAIR)

visual inspection 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,

(J1)

replace the defective parts.

CARRY OUT 4R CHECKS.

VRS1

CN - A

211M -

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