Sharp R-211(W)M User manual

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211M -
S1892R211M///
R
SHARP CORPORATION
SERVICE MANUAL
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
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.
R-211
30
0
23
145
8
9
10
11
12
13
14
15
20
25
30
7
6
ILLUMINATED
TIMER
COOKING CONTROL
WITH COOK & DEFROST GUIDE
0.7
1.0
(KG)
2.0
E

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211M -
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
powerleveltoHIGH(100%)andpushthestartkey.Whentheone(1)minutehaselapsed(timeratzero)carefullycheck
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.
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).
WARNING TO SERVICE PERSONNEL
SERVICING
Microwaveovenscontaincircuitrycapableofproducingveryhighvoltageandcurrent.Contactwithfollowingparts
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.

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211M -
WARNING
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.
CAUTION
MICROWAVE RADIATION
Do not become exposed to radiation from the
magnetron or other parts conducting microwave en-
ergy. All input and output microwave connections,
waveguides, flanges and gaskets must be secured.
Never operate the device without a microwave en-
ergy absorbing load attached. Never look into an
openwaveguideorantennawhilethedeviceisener-
gized.
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
PRODUCT DESCRIPTION
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
CAUTION / WARNING

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211M -
OFF CONDITION
Closingthedooractivatesalldoorinterlockswitches(moni-
tored latch switch and latch switch).
IMPORTANT
When the timer knob is at "0" the oven is in the OFF
condition.
Approx. 10% = 80 Watts
26 sec. ON
4 sec. ON
8 sec. ON
14 sec. ON
20 sec. ON
22 sec. OFF
18 sec. OFF
12 sec. OFF
6 sec. OFF
LOW
MEDIUM HIGH
MEDIUM
MEDIUM LOW
HIGH
Approx. 70% = 560 Watts
Approx. 50% = 400 Watts
Approx. 30% = 240 Watts
Approx. 100% = 800 Watts
HIGH, MEDIUM HIGH, MEDIUM, MEDIUM
LOW, LOW COOKING
When the microwave oven is preset for variable cooking
power,thelinevoltageissuppliedtothepowertransformer
intermittently within a 26-second time base through the
relaycontactwhichiscoupledwiththecurrent-limitingrelay
(RY2). The following levels of microwave power are given.
SETTING
NOTE: TheON/OFFtimeratiodoesnotexactlycorrespond
to the percentage of microwave power, because
approx. 3 seconds are needed for heating up the
magnetron filament.
DOOR OPEN MECHANISM
Figure D-1. Door Open Mechanism
MONITORED LATCH SWITCH (SW1)
STOP SWITCH (SW3)
1. Whentheovendoorisclosed,thecontacts(COM-NO)
must be closed.
2. When the oven door is opened, the contacts (COM -
NO) must be opened.
MONITOR SWITCH (SW2)
1. Whentheovendoorisclosed,thecontacts(COM-NC)
must be opened.
2. When the oven door is opened, the contacts (COM -
NC) must be closed.
3. Iftheovendoorisopenedandthecontacts(COM-NO)
ofthemonitoredlatchswitch(SW1)failtoopen,thefuse
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.
OPERATING SEQUENCE
DOOR SWITCHES
LATCH HOOK
SW3: STOP SWITCH
SW1: MONITORED
LATCH SWITCH
SW2: MONITOR
SWITCH
LATCH
HEADS
OPEN LEVER
DOOR OPEN BUTTON
DOOR

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211M -
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/m2 (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
OUTPUT POWER TEST PROCEDURE

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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.......Checkdiodewhich isconnectedto the relaycoil.If diodeisgood, controlunitisdefective.
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.

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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 3D CHECKS.
STEPS OCCURRENCE CAUSE OR CORRECTION
1 The rated AC voltage is not present at Check supply voltage and oven power cord.
Power terminal of CPU connector (CN-A).
2 The rated AC voltage is present at primary Low voltage transformer or secondary circuit defective.
side of low voltage transformer. Check and repair.
3 Only pattern at "a" is broken. *Insert jumper wire J1 and solder.
(CARRY OUT 3D CHECKS BEFORE REPAIR)
4 Pattern at "a" and "b" are broken. *Insert the coil RCILF2003YAZZ between "c" and "d".
(CARRY OUT 3D CHECKS BEFORE REPAIR)
NOTE: *At the time of these repairs, make a
visual inspection of the varistor for burn-
ingdamageandexaminethetransformer
withtester forthepresence oflayershort
circuit (check primary coil resistance).
If any abnormal condition is detected,
replace the defective parts.
CARRY OUT 4R CHECKS.
(J1)
ab
c
d
VRS1
CN - A
S
P
15

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211M -
DIGITAL ANALOGUE CONTROL PANEL
Control Unit
Control unit consists of LSI, power source circuit, synchro-
nizing signal circuit, ACL circuit, buzzer circuit, encoder
circuit, indicator circuit and potentiometer circuit.
1) LSI
This LSI controls the encoder signal, potentiometer
signal, relay driving signal for oven function, buzzer
signal and LED signal.
2) Power Source Circuit
This circuit generates voltage necessary in the control
unit.
Symbol Voltage Application
VC -5.0V LSI(I-1)
VR -12.0V RELAY(RY1,2)
3) Synchronizing Signal Circuit
The power source synchronizing signal is available in
order to compose a basic standard time in the clock
circuit. It accompanies a very small error because it
works on commercial frequency.
4) ACL
A circuit to generate a signals which resets the LSI to
the initial state when power is supplied.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to
emit audible sounds (key touch sound and
completion sound).
6) Door Sensing Switch (Stop Switch)
A switch to "tell" the LSI if the door is open or closed.
7) Relay Circuit
To drive the magnetron, heating element, fan motor,
turntable motor and light the oven lamp.
8) Encoder
The encoder generates the pulse signal, and the
pulse signal is sent to the LSI.
9) Indicator Circuit
Indicator elements are the Light-emitting diodes
(LD1-LD24).
10) Potentiometer Circuit
The circuit makes setting of the power level by
variable resistance.
OUTLINE OF CONTROL PANEL

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211M -
1 RST IN Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is applied.
Temporarily set to "L" level the moment power is applied, at this time the LSI is
reset. Thereafter set at "H" level.
2 INT IN Signal coming from encoder.
When the encoder is turned, the contacts of encoder make pulse signals. And
pulse signals are input into INT.
3 AVSS IN A/D converter power source voltage.
The power source voltage to drive the A/D converter in the LSI. Connected to
VC.
4 VREF IN Reference voltage input terminal.
A reference voltage is applied to the A/D converter in the LSI.
5K0INSignal coming from potentiometer.
ByinputtingDCvoltagecorrespondingtothepowerlevelsetbythepotentiometer,
thisinputisconvertedintothepowerlevelbytheA/DconverterbuiltintotheLSI.
6K1INTerminal to change functions according to the model.
Signalinaccordancewiththemodelinoperationisappliedtosetupitsfunction.
7 AVDD IN A/D converter power source voltage.
The power source voltage to drive the A/D converter in the LSI.
8 NC No connection terminal.
9 S0 OUT Digit selection signal.
Signal is input to the anodes of the light-emitting diodes (LD19 - LD24).
10 S1 OUT Digit selection signal.
Signal is input to the anodes of the light-emitting diodes (LD13 - LD18).
11 S2 OUT Digit selection signal.
Signal is input to the anodes of the light-emitting diodes (LD7 - LD12).
12 S3 OUT Digit selection signal.
Signal is input to the anodes of the light-emitting diodes (LD1 - LD6).
13-14 NC No connection terminal.
15 D0 OUT Segment data signal.
Signalisinput tothecathodesofthelight-emittingdiodes(LD1,LD7,LD13and
LD19).
16 D1 OUT Segment data signal.
Signalisinput tothecathodesofthelight-emittingdiodes(LD2,LD8,LD14and
LD20).
17 CNVS IN Reference voltage input terminal.
AreferencevoltageisappliedtotheA/DconverterintheLSI.ConnectedtoVC.
18 VSS IN Power source voltage: -5V.
The power source voltage to drive the LSI is input to VSS terminal. Connected
to VC.
19 D2 OUT Segment data signal.
Signalisinput tothecathodesofthelight-emittingdiodes(LD3,LD9,LD15and
LD21).
20 D3 OUT Segment data signal.
Signalisinputtothecathodesofthelight-emittingdiodes(LD4,LD10,LD16and
LD22).
21 D4 OUT Segment data signal.
Signalisinputtothecathodesofthelight-emittingdiodes(LD5,LD11,LD17and
LD23).
22 D5 OUT Segment data signal.
Signalisinputtothecathodesofthelight-emittingdiodes(LD6,LD12,LD18and
LD24).
DESCRIPTION OF LSI
LSI(IZA882DR)
The I/O signal of the LSI(IZA882DR) are detailed in the following table.
Pin No. Signal I/O Description
DIGITAL ANALOGUE CONTROL PANEL

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211M -
Pin No. Signal I/O Description ON/OFFtimeratioinMicro
cooking
(a. 32second time base)
MICRO ON OFF
COOK
100% 32sec. 0sec.
70% 24sec. 8sec.
50% 18sec. 14sec.
30% 12sec. 20sec.
10% 6sec. 26sec.
23 D6 OUT Magnetron high-voltage circuit driving signal.
Toturnonandoffthecookrelay(RY2).
In 100% POWER operation, the sig-
nals hold "L" level during microwave
cooking and "H" level while not cook-
ing.Inothercookingmodes(70%,50%,
30%, 10%) the signal turns to "H" level
and "L" level in repetition according to
the power level.
24 D7 IN/OUT Terminal not used.
25 D8 OUT Oven lamp, turntable motor and fan motor driving signal(Square Wave-
form : 50Hz).
To turn on and off shut-off relay
(RY1). The square waveform
voltage is delivered to the relay
(RY1) driving circuit and
relay(RY2) control circuit.
26 NC No connection terminal.
27 F0 IN Inputsignalwhichcommunicatesthedooropen/closeinformationtoLSI.
Door closed; "H" level signal.
Door opened; "L" level signal.
28 F1 Terminal not used.
29 F2 IN Signal to synchronize LSI with commercial power source frequency.
This is basic timing for all real time
processing of LSI.
30 F3 IN Signal coming from encoder.
Signal similar to INT. Pulse signals are input into F3.
31-32 NC No connection terminal.
33 XOUT OUT Internal clock oscillation frequency control output.
Output to control oscillation input of XOUT.
34 XIN IN Internal clock oscillation frequency input setting.
The internal clock frequency is set by inserting the ceramic filter oscillation
circuit with respect to XIN terminal.
35 CNTR OUT Signal to sound buzzer.
A: key touch sound.
B: Completion sound.
36 VDD IN Power source voltage: 0V.
The power source voltage to drive the LSI is input to VDD terminal.
20 msec
During cooking
H
L
20 msec
H : GND
L (-5V)
A
BH: GND
L: -5V
0.12 sec
2.4 sec
DIGITAL ANALOGUE CONTROL PANEL