Sharp R-7370 Service Manual

be restored to its original condition and only *parts identical to those specified be used. /-- \ This is a supplemental Service Manual for R-7370. These models are quite similar to Base Model R-7260. Model R-7370 has Reheat Sensor and Compu Defrost functions in addition, compared to base model R-7260. Use this supplemental manual together with the Base Service Manual. Refer to the Base Service Manual for complete operation, service information, etc. / TABLE OF CONTENTS \ Page FOREWORD ...................................................................... 1 CAUTION, MICROWAVE RADIATION ................................................... 1 THUMB INDEX ................................................................... 1 PRODUCT DESCRIPTION ............................................................ 2 OPERATING INSTRUCTIONS ......................................................... 3 SERVICING ...................................................................... 8 TOUCH CONTROL PANEL ASSEMBLY ................................................. 10 MICROWAVE MEASUREMENT ....................................................... 23 SCHEMATIC DIAGRAM ............................................................ 24 PICTORIAL DIAGRAM ............................................................. 24 CONTROL PANEL CIRCUIT.. ....................................................... 25 PRINTED WIRING BOARD .......................................................... 26 PACKING AND ACCESSORIES.. ..................................................... 27 PARTS LIST .................................................................... 28 SHARP CORPORATION

Oven. These models are quite similar to Base Model R-7260. lt is recommended that service personnel carefully study the entire text of two Manuals (Base manual and this manual), SO they will be qualified to render satisfactory customer service, 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 energized. SHARP CORPORATION OSAKA, JAPAN

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. Materials with a high moisture content, like most foods, will absorb microwave energy. As the microwave energy at a fre- quency of 2456 Megahertz enters the food, the molecules align themselves with the energy. Because the microwaves are changing polarity every half cycle, the food molecules are Microwaves, which are short electromagnetic waves of RF (radio frequency) energy, pass through materials such as glass, paper, china and most plastics. Materials such as metal and aluminum foil tend to reflect microwaves and may be used only as recommended in the cooking instructions. changing direction every half cycle or oscillating back and forth 4,900,000,000 times per second. This high speed oscil- lation causes friction between the molecules, thereby convert- ing the microwave energy to heat. Power requirements Power consumption Microwave output power 650W (2 litre water load) Case dimensions Width Height Depth Cooking cavity dimensions Width Height Depth Turntable diameter Control complement Weight SPECIFICATIONS 240V 50Hz Single phase, 3 wire earthed 1.3kW 550mm 336mm 403mm 345mm 217mm 344mm 325mm Start Pad. Stop/Clear Pad. Clock (1 :00 - 12:59) Minute Timer (0 - 99 minutes 99 seconds) Variable Cooking Control Repetition Rate: HIGH Full power throughout the cooking time. MED HIGH Approx. 24 sec. ON, 8 sec. OFF, approx. 70% of full power. MED Approx. 18 sec. ON, 14 sec. OFF, approx. 50% of full power. MED LOW/DEFROST Approx. 12 sec. ON, 20 sec. OFF, approx. 30% of full power. LOW Approx. 6 sec. ON, 26 sec. OFF, approx. 10% of full power. Reheat Sensor, Compu Defrost. - c Approx. 2 1 kg. 2

at HlGcl or tncrease 1 m,nure by 1 minute mumpies durmg varmie cookmg i c omx>u DefrostTM / L * 1 Your Sharp Microwave Oven has special function keys to defrost meats and poultry faster and better. Compu Defrost automatically defrosts roast beef, pork, steaks, chops, minced beef, whole chicken and chicken pieces. Each key has 3 defrosting stages. Step 1. 2. 3. 4.- lose you want to defrost 1.36 Kg steak with COMPU DEFROST. Procedure Pad Order Touch the COMPU DEFROST pad. Select desired’ COMPU DEFROST setting. Touch 2 to defrost steak. Touch number pads to enter weight. IEx. 1.36 kg should be 1.4 kg) Touch START pad. [X] w 0 START Display [ will flash and COMPU DEFROST will ap- pear on display. Kg. will flash on and off. Kg. stops flashing and re- mains on display. I COMPU OEMIST ME0 HIGH I ’ COOK Defrosting time, variable power of the first stage and COOK will appear on display. The timer will begin to count down. When the 1st stage finishes, an audible signal will sound 4 times 3nd oven will stop. COOK indicator will go off. I=] [=I and m jm] will be displayed repeatedly. 3

!]and ISTRR:] will any warm portions. be displayed repeatedly. Return food to the oven. Close the door. 6. Repeat step 4. 7. Reheat step 5. !TETTl jEU”=li’] will be displayed repeatedly. jFRESSI t and i 5 T,q&‘Tj will be displayed repeatedly. 8. Touch START pad. The timer will begin to count dowh. When the 3rd stage finishes, an audible signal will sound. COOK indicator will go off. [ S T 8 I”: 2 j w i I I be dis- played. When door is opened or STOP/CLEAR pad is touched, !STfi::Z will go out and the time of day will appear on the display. NOTE: 1. When keying in the weight, the unit must be rounded off to the nearest 0.1 Kg. eg. 1.65 kgh1.7 kg 2. Foods weighing more or less than the quantity listed in the guide should be defrosted following guide- lines in the cookbook. If the incorrect weight is entered and START pad is touched, E RR3R; and incorrect weight will be displayed repeatedly. The STOP/CLEAR pad has to be touched to reprogramme the oven. 3. Foods not listed can be defrosted using defrost setting. 4. Large objects/quantities require turning or stirring or re-arranging. 5. Arrange food in single layers where possible. If food is in a block, try to separate as soon as possible. 6. Foil-use foil to shield and protect outer edges, thin areas, fatty areas, near bones etc. N.B. Too much foil causes part uncovered to start to cook. Foil shouldn’t touch sides of oven. If arcing occurs, caused by foil touching sides, stop oven and repo- sition food. If any area begins to feel warm, shield with foil and secure with a wooden toothpick. Joint of Meat Poultry foil 7. Food should be cooked directly after defrosting and standing (where applicable). 4

Compu Defrost Pood Setting Amount Display Procedure Comment 7 Minced beef 0.5 r r ii r-7 T1 I I- CJ LJ JJ / l Before defrosting.. . Stand, covered I ICE - 1 r i r*n \,,-, 1 I 1-l Y c l Remove any thawed 10 - 15 minutes. 2 5 kg \Fijf:;7“::‘; pieces after each stage. L Steak 0.2 1 :=&Tu”] l Before defrosting I Shield the edge and 2.0 kg , the thin portions. T : I f-r AI : , l-7 \ , /- n -8 1-T ’ ” IJ ” 1: 87 1 l After the 1 st stage... x , I- nticO 1 c-nit= I Turn over and shield L ‘J ” ,- I * i LI 1-l i the warm portions. ’ I- 1-l * 1 C 0 ’ i c I, ,J t - 7 /- - LU

WORKS Sharp’s Electronic Sensory Processor is a semi-conductor device that detects the vapor (humidity) emit- ted from food as it heats. The Sensor adjusts heating times and variable power for various foods and quan- tities. It takes the guesswork out of microwave heating. HERE’S AN EXAMPLE OF HOW IT WORKS: +“c* 1 SENSOR ‘1 0% kc J ; i f’:’ I 1 y&i, ir; ‘I/ > \ ek BROCCOLI 1. Broccoli at room temperature. 2. Heat Broccoli. Vapor is emitted 3. Sensor detects vapor and cal- Vapor is emitted very slowly. rapidly. culates cooking time and vari- Before You Use REHEAT SENSOR able power. 1. The oven should not be operated on Sensor Reheat immediately after plugging in the unit. Wait 5 minutes .before using the Sensor Reheat. 2. The Reheat Sensor is designed to work best for reheating precooked foods. The Reheat Sensor may not work perfectly with all menus. Please refer to Reheat Chart for available menus. 3. Be sure the exterior of the cooking container and the interior of the oven are dry. Wipe off any moisture with a dry cloth or paper towel. 4. Room temperature should not exceed 35OC. 5. Dense casseroles are difficult to heat with the Reheat Sensor and may be too cool. Stirring the cas- serole after heating will help to equalize temperatures. 6. If the Reheat Sensor has not detected the vapor of the food after 15 minutes,, E fF R /I7 ,? /and LR E - , HER T j will appear in the display and the oven will shut off. Preparing Foods 1. Reheat Sensor works with foods at normal storage temperature. For example, chicken pieces would be at refrigerator temperature and canned soup at room temperature. 2. A minimum quantity of a half cup should be heated when using the Reheat Sensor. Smaller quantites should be heated by time and variable power. 3. Should foods be cooler than desired, simply heat an additional minute or two using Instant Cook. 4. If a particular food is hotter than desired, consult your cookbook or cooking guide and choose time and variable power the next time the food is heated. 5. The arrangement of foods will affect heating results. Place the thickest parts of foods to the outside of the dish, where they will receive more microwave energy. 6. When possible, stir foods before eating. Covering Foods Foods should be covered with plastic wrap or casserole lid when using the Reheat Sensor. Other cover- ings may cause foods to overheat. 1. Casserole lid. 2. Plastic wraps. Use plastic wraps recommended for microwave cooking. Cover dish loosely; fold excess wrap over side of dish. Do not create an air tight seal, follow procedure in chart. Be careful when removing any covering to allow steam to escape away from you. 1. Casserole lid 2. Plastic wrap 6

To use the Reheat Sensor, open oven door, place food in oven, close door and touch REHEAT SENSOR pad. REHEAT SENSOR pad must be touched within one minute after closing oven door or touching the STOP/CLEAR pad. * Suppose you want to reheat vegetables. Step Procedure 1. Touch REHEAT SENSOR pad. Pad Order I REHEAT SENSOR 1 Display I / SENSOR I-i r i COOK IT I,- - I I I ~~~;~R COOK They will be displayed con- tinuously. The oven will start operating. When the food is hot as detected by the reheat sensor, all indicators will go out and an audible signal will sound. The time of day will reappear on the display. NOTE: Avoid opening the oven door or touching STOP/CLEAR pad when 1 ?E - : / ,5rE ,q T : is dis- played. if this occurs, / 15 R ,?‘,T /? / andmy/ 8 E R T

please refer to Service Manual for Base Model R-7260 etc. PROBLEM POSSIBLE CAUSE TEST PROCEDURE OR CORRECTION SENSOR COOKING Oven is in the sensor cooking con- dition but RH sensor does not end stage 1. of cooking cycle, cooking cycle or does not step cooking cycle. RH sensor open and/or short. Defective control unit Open or loose wire connection to the above components. Procedure M. Procedure M. Check and repair wiring. TEST PROCEDURES (CONT’D) I KEY UNIT / PROCEDURE LETTER COMPONENT TEST K KEY UNIT TEST If the Indicator does not respond to touching a key Pad use the following matrix and place a jumper wire between the proper pin connections with the G (l2-pin) cabie disconnected from the control unit. If the indicator responds and oven goes into operation, the key unit is faulty. If there is no response, replace the control unit. 8

PROCEDURE LETTER COMPONENT TEST M REHEAT SENSOR CIRCUIT Water Load Cooking Test Check as follows: (1) Fill 100 milliliters (3.6 oz) of tap water initially at 20 + 1 OC (68°F) in a 500 milliliter measuring cup. (2) Place the container on the center of turntable tray in the oven cavity. (3) Close the door, and touch “REHEAT SENSOR” pad. (4) The oven is in the sensor cooking condition. (5) Sensor cooking time should be 3 min. * 75 seconds. Checking the Control Unit with Use of Dummy Resistor (1) Take the procedures according to the instructions in “Servicing of Touch Control Panel”. Besides it is needed to connect the parts as shown in Fig. A to the connector (C) to enable checking of the REHEAT SENSOR. (2) Check the sensor cook operation proceed as follows: (2-l 1 Touch “REHEAT SENSOR” pad. (2-2) The control panel is in the sensor cooking operation. (2-3) After approximately 40 seconds, push plunger of MICRO switch. This condition is same as judgement by REHEAT SENSOR. (2-4) After approximately 3 seconds, cooking operation turns off, an audible signal will sound, and the display will then revert to the time of day. If the above is not case, the control unit is probably defective. If the above is proper, the REHEAT SENSOR is probably defective. MICRO SWITCH COM/ 39kn 1/4W &S’rC * Sensor CLIP Connector CONNECTOR on Control t4!55n tw fS% Panel 0 b - C-f -c-2 -c-3 Figure A. Sensor Dummy Resistor Circuit 9

The touch control section consists of the following units as shown in the block diagram. (1) Key unit (2) Control unit Exchange of signals between each unit is indicated by the ar- rows in the block diagram. The principal functions of these units and the signals communicated among them are explained below. l-l. Key Unit The key unit is composed of a matrix, signals generated in the LSI are sent to the key unit through P62, P63, P70 - P73. When a key pad is touched, a signal is com- pleted through the key unit and passed back to the LSI through PlO - P13 to perform the function that was requested. l-2. Control Unit Control unit consists of LSI, Power source circuit, Syn- chronizing signal circuit, ACL circuit, Buzzer circuit, Reheat sensor circuit and Indicator circuit. 1) Power Source Circuit This circuit generates voltage necessary in the control and indicator circuit, from the AC line voltage. In ad- dition, the synchronizing signal is available in order to compose a basic standard time in the clock circuit. 2) Synchronizing Signal Circuit The power source Synchronizing signal is available in order to compose a basic standard time in the clock ci rcu it. It accompanies a very small error because it works on the commercial frequency. 3) LSI (IX2412YA) This LSI controls the reheat sensor signal, key touch and relay control signal for oven function, and control of the indicator circuit. 4) ACL A circuit to generate a signal which resets the LSI to the initial state when power is supplied. 5) Stop switch A switch to “tell” the LSI if the door is open or closed. 6) Buzzer The buzzer is responsive to signals from the LSI to emit noticing sounds (key touch sound and completion sound). 7) Relay Circuit To drive the magnetron, fan motor, turntable motor and light oven lamp. 8) Reheat Sensor Circuit This circuit detects moisture of a food which is under cooking, to allow its automatic cooking. 9) Indicator Circuit This circuit consists of 6-digits, 13 segments display, five cooking mode indicators. 10

G? 3- is -Jl- a > b 2 ~22~2”‘~gg~ aaQanZaen..a CVFOC3N cnmmccco QQQQQ s Iv z 2 . . 5 - w Ti 58 iz P 5 . 0” 2 c .- Q f z d Q z : .- s 75 PC e I- t! 33 .- u.

P30 1 2 Signal P20 P21 P22 P23 P30 P31 Segme .............. d .............. C .............. b nt OUT OUT OUT P31 P32 I ‘r-d ;I 1, : Gw :; II M:D j; H;);H ,I/ I P33 . . * . . . . . . *... * a i AUTO 1: II / I // -LiB-- ‘/ I ,I LB ,i---4i--_-~~L-----~ j COOK :/ LB ‘I s............. e . . * . . ...* . . . . . f P32 .............. g 1.68 msec. P33 .............. h --- GND P40 .............. i a .......... DEFROST Segment P41 j b .......... SENSOR .............. II-- Signal P42 .............. k -27V IN Auto-clear terminal ACL CL1 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. I I j 6 IN Internal clock oscillation frequency setting input. I The internal clock frequency is set by inserting the ceramic filter oscillation circuit with i respect to CL2 terminal. OUT Internal clock oscillation frequency control output. Output to control oscillation input of CLl. CL2 P40 OUT Segment data signal. Signal similar to P30. TEST IN Not used. Connected to VDD (-12V). P41 OUT Segment data signal. - Signal similar to P30. OUT P42 12 P43 OUT Signal for lighting of Power level and COMPU indicators. Signal similar to P30. 13 P50 OUT Signal for lighting of COOK, AUTO and kg indicators. Signal similar to P30. 14 P51 IN -4 Terminal not used. / / IN 15 P52 16 IN IN Not used. Terminal for manufacture test. 1 17 18 19 P53 P60 I’61 P62 20 P63 I IN Terminal not used. I OUT Key strobe signal. Signal applied to touch-key section. A pulse signal is input to PlO - P13 terminal while one of G-l line keys on key matrix is touched. OUT Key strobe signal. Signal applied to touch-key section. A pulse signal is input to PlO - P13 terminal while one of G-2 line keys on key matrix is touched. 13

Signal applied to touch-key section. A pulse signal is input to PlO - P13 terminal while one of G-3 line keys on key matrix is touched. Key strobe signal. Signal applied to touch-key section. A pulse signal is input to PlO - P13 terminal while one of G-4 line keys on key matrix is touched. Key strobe signal. Signal applied to touch-key section. A pulse signal is input to PlO - PI3 terminal while one of G-5 line keys on key matrix is touched. Kev strobe signal. Signal applied to touch-key section. A pulse signal is input to PlO - P13 terminal while one of G-6 line keys on key matrix is touched. Terminal not used. Sinnal to sound buzzer. A: Key touch sound. B: Completion sound. 0.12 sec. A. -//- B l . r l , l rZWurrc,i r.L*f -25,“* T T4oor10-• _ Not used. Power source voltage: -12V. VDD Voltage of power source circuit input Terminal not used. Connected to GND. Terminal not used. Used for initial balancing of the Reheat Sensor circuit 14

This input is an analog input terminal from the RH sensor circuit, and connected to the A/D converter built into the LSI. 40 PO1 IN Terminal to change the functions according to the Model. By using the A/D converter contained in the LSI (IX2412YA), DC voltage in accordance with the Model in operation is applied to set up its function. Not used. Connected to GND. 41 PO2 IN 42 PO3 IN Terminal to change the 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. 43 Signal coming from touch-key. When either one of G-l 1 line keys on keys on key matrix is touched, a corresponding signal out of P70 - P73, P63 and P62 will be input into PIO. When no key is touched, the signal is held at “L” level. PI0 PI1 IN IN 44 Signal similar to PlO. When either one of G-IO line keys on key matrix is touched, a corresponding signal will be input Pll. 45 P12 IN Signal similar to PlO. When either one of G-9 line keys on key matrix is touched, a corresponding signal wiil be input PI 2. IN 46 47 48 PI3 AGND Signal similar to PIO. When either one of G-8 line keys on key matrix is touched, a corresponding signal will be input P13. IN Connected to GN D. Digit selection signal. The relation between digit signal and digit are as follows: Digit Signal Digit PA4 . . . . . . . . . . . 1st PA5 . . . . . . . . . . . 2nd 1.32 msec. PA6 . . . . . . . . . . . 3rd PA7 . . . . . . . . . . . 4th PA4 PA8 . , . . . . . . . . . 5th PA9 . . . . . . . . . . . 6th r--------- ;;;” Normally, one pulse is output in every I3 period, and input to the grid of the Fluorescent Display. PA5 n PA6 n PA7 [ PA6 fl PA9& T:c, 1.32 msec. 15 PA9 OUT OUT 49 PA8 PA7 50 OUT OUT 51 PA6 52 PA5 OUT 53 PA4 OUT

50Hz). To turn on and off the shut-off relay (F$Y I) : The Square waveform voltage (50Hz) is delivered to the RYI driving circuit and RY2 control circuit. 20 msec. L- - ----- GND , L -19v During cooking or when door is opened. 55 ’ PA2 ’ OUT ’ Magnetron high-voltage circuit driving signal. To turn on and off the cook relay (RYZ). In HIGH operation, the signals holds “H” level during microwave cooking and “L” level while not cooking. In other cooking modes (HIGH, M-HIGH, MED, M-LOW, LOW) the signal turns to “H” level and “L” level in repetition according to the power level. HIGH JJ ME0 HIGH 56 57 58 32 WC. J I HOLD e-m L Vdisp IN Anode (segment) of Fluorescent Display light-up voltage: -27V. Vp voltage of power source circuit input VR IN Reference voltage input terminal. A’reference voltage applied to the A/D converter in the LSI. The reference voltage is generally maintained at -6.15V. PA1 IN Signal synchronized with commercial source frequency. This is the basic timing for time processing of LSI (ICI: lX2412YA). 20 msec. 16

the door open/close information to LSI. Door closed: “H” level signal (OV) Door opened: “L” level signal (-12V) 60 P20 61 P21 OUT Segment data signals. --- Signal similar to P30. OUT 62 P22 63 P23 OUT OUT I 64 / GND ) IN ) Connected to GND. I POWER SOURCE CIRCUIT A power of AC 240V is applied to the primary winding of transformer (Tl). The output voltage of the secondary winding of transformer (Tl) is then full-wave rectified by the diode bridge (Dl) and smoothed by the electrolytic capacitor (C2) to become DC voltage VC. Then the voltage VC is delivered to the constant voltage circuit. VDD f-12V) is a voltage to be applied to the LSI. Tl Dl POWER SUPPLY 240V 50Hz VRSl t To Relay Confact Figure T-3. Power Source Circuit 17

power source circuit there is caused AC half-wave rectified voltage and it is applied via R7 to PA1 terminal of LSI. This voltage is referred to as a power sync. signal. R7 58 > T 1 (gk) R8t t”” ** PA1 LS I I I I- 20.0 msec. -I Figure T-4. l3 Circuit and Waveform ACL CIRCUIT By switching on power, charge current (il) is fed to C20 through R20 and generates throshold voltage (Vz). If Vz exceeds the zener voltage of ZD20, ZD20 is turned on and the current i2 flows. Thus, placing voltage on to the base of transistor Q20 and turning it on. A reset signals is obtained from the collector. C21: Noise filter capacitor. GND, a v a-- l 1 RESFT GND J RESET Figure T-5. ACL Circuit 18

waveform voltage (2.5 kHz) is applied to SPl to generate buzzer sound. 030 I- -------l I ; (From LSL) SPl Dp~~~“-T-;;y~; L ----- J T J u-uzv sp]Ga L-r’:” Figure T-6. Buzzer Circuit RELAY CIRCUIT While the unit is in cook, “H” level signal is produced at PA2 terminal of LSI and also a pulse signal at PA3 terminal of LSI. The pulse signal form PA3 terminal is applied to the rec- tifier circuit made up of Diodes DlOO and DlOl inside the hybrid IC (IC3) where it is made into DC signal to charge Cl 00. With Cl00 charged up, 0100 and QlOl turn on in succession so that a current I1 is caused to turn on the control relay (RY 1). The “H” level signal from D6 terminal is applied to Q80 which is connected in series with QlOl, and current i2 made only when both Q80 and 0101 are turned on at the same time allowing the cook relay (RY2) to turn on. To Power Source Circait RY2 1 (COOK RELAY) RYl P I I j i2 1 R103 0101 Cl01 44h 15 R105 IC3 : Hybrid IC Figure T-7. Relay Circuit 19

1. Operational Principle of Reheat Sensor As shown in Fig. T-8,2 pieces of temperature sensitive resis- and RH, are used in the detector of the reheat sensor. These temperature sensitive resistors are cased for protection. Fig. T-9 shows the basic circuit. The temperature sensitive resistor RH, is receiving approx. 52mA of current at all times, keeps itself heated to approx. 460°F (24OOC). A minute current is applied to the temperature sensitive resis- tor RN to measure the ambient temperature. VOUT (output voltage) in Fig. T-g can be expressed as follows. VOUT = RH - - lo l Rf RN Where, IO is a- constant current and Rf is a fixed resistance. Therefore, VOUT will be the voltage in proportion to the resistance ratio between RH and RN. The temperature sensitive resistors RH and RN have a linear and positive characteristic against the temperature. Therefore, when the temperature is the only varying force with humidity being constant, -%- value at a constanP evel. r becomes constant, keeping VOUT When vapors are produced from the food, the RH resistor side is cooled down reducing the temperature, making the resistance lower. Therefore, a VOUT voltage is generated in proportion to the variation of vapor volume. Internal Structure of Rrl Sensor Figure T-8. Operational amplifier Figure T-9. output voltage When this voltage level reaches the preset detection point, the cooking is terminated. If the initial voltage setting cannot be made due to open or short-circuit the of sensor elements approximately 40 seconds after the sensor cooking was started, the indicator shows ER- ROR and sensor cooking is terminated. 2. Reheat Sensor Circuit This circuit is composed of a part which transmits a change of the reheat sensor voltage to PO0 terminal of LSI and of the which supplies a constant current to the temperature sensi- tive resistor RH. When sensor cooking is started, 16 seconds of cleaning time will foliow to let out residual moisture. After this cleaning time, the magnetron is oscillated. Forty se- conds later, SW1 to SW5 in LSI are turned on so that the in- put voltage to PO0 terminal of LSI will become approx. -4.8V. Then, in compliance with the changes of vapor volume com- ing from the food, the resistance ratio between RN and RH varies to feed PO0 terminal of LSI with the voltage in propor- tion to this ratio. Figure T-10. 20

having a cathode, a grid and an anode. Usually, the cathode of Fluorescent Dis- play is directly heated and the filament serves as cathode. When a proper voltage is applied to the filament to heat it, thermo-electrons are emitted and, with positive voltage with respect to filament being applied to the anode and grid, elec- trons hit against the anode to illuminate the fluorescent body. If the anode or grid voltage is zero or negative against the fila- ment, thermo-electrons can not reach the anode, hence the fluorescent body is not luminescent. The followmg signals are responsible for specxfyrng segments. CIRCUIT In this model, the Fluorescent Display 6-digits, 13segments are used for displaying figures. The Fluorescent Display employs the dynamic drive method, when the high level of anode signal and grid signal agree, the corresponding segment displays. Segment Character format 1 d [ M.HIGH I P43 I I P43 , 1-1 Ml- 1 HIGH ‘-1 caror 1 COMPU j ’ P43 I AUTO P50 Kg P50 COOK P50 , DEFROST P23 SENSOR , P22 V&p b Filament yi Digure T-l 1. Indicator Circuit 21

LSI in the integral part of the circuits. When handling these parts, the following precautions should be strictly followed. PMOS LSI have extremely high impedance at its input and output terminals. For this reason, it is easily influenced by the surrounding high voltage power source, static electric- ity charged in clothes, etc, and sometimes it is not fully pro- tected by the built-in protection circuit. 1) When storing and transporting, thoroughly wrap them in aluminum foil. Also wrap PW boards containing them in aluminum foil. 2) When soldering, ground the technician as shown in the figure and use grounded soldering iron and work table. 2. Shapes of Electronic Components 1 Transistor Transistor Regurator IC Hybrid IC 2SB953 DTC114EA AN79L12 IC3, lC4 1: OUT Terminal 2: COMMON Terminal 3: IN Terminal 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 out 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 you from touching the high voltage transformer, or unplug the promary terminal (con- nector) 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 between 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 con- trols (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-re,iated 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 such an operational state that is equivalent to that with the oven door being closed. And connect an exte’rnal 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 (11-B above, it is here also possible to check the sensor-related controls of the touch control panel by us- ing the dummy resistor(s). 4. Sevicing Tools Tools required when servicing the touch control panel as- sembly. 1) Soldering: 30W (To prevent leaking current, it is recommended to use a soldering iron with grounding terminal.) 2) Oscilloscope: Single beam, frequency range: DC - 10MHz type or more advanced model 3) Others: Other tools 5. Other Precautions 1) When 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 ab- normal voltage due to static electricity etc. is not ap- plied to the input or output terminals. 4) Attach connectors, electrolytic capacitors, etc. to pW board, taking care that all connections are tight. 5) Be sure to use specified components where high preci- sion is required. 22

and door is com- pleted individually or collectively, 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 ex- ternal surface of the oven. PREPARATION FOR THE TESTING: Before beginning the actual test for leakage, proceed as foilows; 1. Make sure that test instrument is operating normally as specified in its instruction booklet. Important: Survey instruments that comply with the requirement for instrumentation as prescribed by the performance standard for microwave ovens must be used for testing. Recommended instruments are: NARDA 8100 NARDA 8200 HOLADAY HI 1506 SIMPSON 380M 2. Place the turntable tray into the oven cavity. 3. Place the load of 275 fl5ml of water initially at 2025°C in the centre of the oven tray. The water container should be a low form of 600ml 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. 4. 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. 5. Move the probe slowly (not faster that 2.5cm/sec.) along the gap. 6. The microwave radiation emission should be measured at any point of 5cm or more from the external surface of the oven. 23

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I PACKING ADD KIT 0 WADBWBBYBEO) , If (SPAKCA233WREO) 1 I 2 1 3 I 4 I * Not Replaceable Items 5 I 6 27

1 1 AZ 2- 2 MSPRTO 10 OWRE 0 Open lever spring / 1 AA 2- 3 GDA i -A0 2 lWRW0 Unit chassis I I 1 AR 2- 4 lGLEGPOOZlWRE0 Foot 1 2 AB 2- 5 / L STP P 0 0 6 5WR F 0 Cord anchorage (upper) 1 AB 2- 6 L S T P P 0 0 6 6 W R F 0 Cord anchorage (lower) 1 AB 2- 7 P S P AGQ 0 0 2 Y B E 0 Vibration proof cushion 1 AA 2- 8 TMAPCA 14 4WR R 0 Schematic diagram 1 AB 2- 9 LANGK 0 2 4 3WRW0 Capacitor holder 1 AC Z-10 PDUC-0502WRF0 Fanduct 1 AG 2-11 FFANJ0031WRKO Fan blade 1 AF 2-11 A LSTY-0 0 3 OWRE 0 Fan retainer clip 1 2-12 LANGF0334WRPO Chassissupport I AA 1 AD 2-13 LANGT 0 4 1 lWRW0 Control panel back plate 1 AH 2-14 LANGK0371WRFO Upperlatch hook 1 AD 2-15 LANGK0381WRFO Lowerlatch hook 1 AD 2-16 ML E V F 0 1 2 4 WR E 0 Monitor switch lever 1 AC 2-17 MLEVP0099WRFO Switch lever 1 AB 2-18 ML EVF 0 2 8 9WRWO Open lever 1 AC I . -I.- -- I I ..C1. a I IIG purls 1ilarKeo are usea in voltage more man z3uv. l- 1 1 QACCAA 0 0 7WR E 0 Mains supply cord 1 AQ l- 2 FDTCTAO 2 3WRK0 RH sensor-. 1 AS l- 3 ,QFS-C0019WREO FuseM6.3A 1 AE l- 4 QFSHDOO 19WREO Fuse holder 1 AF l- 5 QFS-T0026WREO Temp. fuse (115°C) 1 AG l- 6 Q SW-MO 1 7 2WR E 0 Monitor switch (V-16G-2C25) 1 AG l- 7 QSW-MO 1 7 3WR E 0 Upper and lower latch switch (V-16G-3C25) 2 AG l- 8 RH-DZAO 0 2WR E 0 Short protector 1 AQ l- 9 RLMPT0036WREO Oven lamp 2 AK l-10 lRMoTE0184WREO Fan motor 1 AW l-11 RMbTDO 0 8 1WR E 0 Turntable motor / 1 AT Q SW-M 0 1 7 4 WR E 0 ’ ! l-12 Stop switch (V-5330DK) 1 AH l-13 , RT RN-A 0 5 1 WR E 0 Transformer for control unit 1 AU l-14 RC-QZA 0 0 9WR E 0 - High voltage capacitor 1 AY l-15 RH-DZAO 0 1WR E 0 Rectifier 1 AM l-16 RT RN-A 0 5 2WR E 0 Power transformer 1 BP l-17 RV-MZA008WREO Magnetron 1 BL CABINET PARTS 28

3- 1 CPWB F 2 0 7 SWR K 0 Control unit 1 BT 3- 1A QPLGJ2381YAZZ 4-pinconnector 1 AC 3- 1B QPLGJ2255YAZZ 3-pin connector(B) 1 AB 3- 1c QPLGJ2362YAZZ 3-pinconnector 1 AB 3- 1D QPLGJ2335YAZZ 4-pinconnector 1 __--- AC --- 3- 1 E,.- 3-G QPLGJ2299YAZZ‘ i$nconnector(F) 1 AD QPLGJ 233 2YAZZ 12-pin connector(G) 1 AE 3- 1G R V-K X 2 0 4 4 Y A Z Z Fluorescent display tube 1 ’ / AX 3- 1H PCUS-2 0 1 1 YAZZ Tube cushion i 2 / AA Cl VCQYCUlHM104K Capacitor O.lpF 5ov 1 1 AB c2 VCEAAHlHM108M Capacitor 1000,uF 5ov A c3 VCEAAA 1 EM3 3 7M Capacitor 33OpF 25v ll D 1 C4,C6,C7 i AC VCKYAT 1 EX 15 3 N Capacitor O.O15/1F 25V 6 C21,C93, ( AA c94 c5 VCEAAA 1 EM4 7 6M ’ Capacitor 47pF 25V I l c20 VCEAAA 1 HM2 2 5M 1 AB Capacitor 2.2/1F 5ov 1 j AA c40 VCKZPUlHF103Z Capacitor O.Ol,uF 5ov 1 ’ AA c70 VCEAAA 1 HM3 3 7M Capacitor 330,uF 5ov 1 AD C71,C72 VCTY PU 1 E F 1 0 4 Z Capacitor O.lfiF 25V 2 AB C9O,C91 VCCCPR 1 H3 2 2 1 J Capacitor 22OpF 5ov AB CF90 RCRS-2 0 0 9YAZZ Ceramic filter (400kHz) I : 1 AF , Dl RH-DX 2 0 0 6 Y AZ Z Diode bridge (SlWBAlO) 1 ’ AE D2, D70 VHDl lESl/‘//-1 Diode (11ESl) 2 AB D3 VHDlSS133//-1 Diode(lSS133) 1 AA D80, D81 VHDUS 10 6 O//-l Diode (USlOSO) 2 AA Fl QFS-A20 1 OYAZZ Fuse 1 AF ICl RH-iX2412YAZZ LSI 1 AV IC2 RH- i X24 14YAZZ Regulator IC 1 AE IC3 RH-iX2413YAZZ Hybrid IC 1 AL IC4 Q~iCA4189KAzz HybridIC 1 AL Ll RCi LF2003YAZZ Coil (22pH) 1 / AC Ql VS 2 SA7 15-B/- 1 Transistor (2SA715B, C) 1 AD 420 VSDTA- 14 3 -A- 1 Transistor (DTA143EA) 1 AC Q3O,Q80 V S DTC- 1 14 -A- 1 Transistor (DTC114EA) 2 AC 470 V S 2 S B 9 5 3 -Q/- 1 Transistor (2SB953Q, R, P) 1 AG Rl VRD-ST2EFGR8 J Resistor 6.8a 1/4w 1 AA R2 VRD-ST2 EF 10 2 J Resistor lkfi 1/4w 1 AA 29

Resistor 82Oa 1/5w 1 AA R5 VRS-FT3AB8 2 1 J Resistor 82OQ 1W 1 AA R7,R8 VRD-ST2DF473 J Resistor 47kn 1/5w 2 AA R20,R21 VRD-ST2DF 10 3 J Resistor 1Okn 1/5w 2 AA R30,R40 VRD-ST 2 DF 3 3 2 J Resistor 3.3ka 1/5w 2 AA R50 RR-KZ 2 0 5 0 Y AZZ Resistor block 150kQX4 1 AB R70 VRN-RT2DC9 12F Resistor 9.1 kfi(F) 1/5w 1 AA R71 VRN-RT2DC474F Resistor 470kfi(F) 1/5w 1 AA R73 VRN-RT2DC3 4 2 F Resistor 3.4ka(F) 1/5w 1 AA R74 VRD-ST2HA62 0 J Resistor 62L? 1/2w 1 AA R90 VRD-ST2DF 10 5 J Resistor 1Mfi 1/5w 1 AA RYl,RY2 RRLY-2 102YAZZ / Relay (18V. D. C) 2 AD SPl RALMB2023YAZZ ’ Buzzer v 1 AG VRSl RH-VX20 19YAZZ Varistor 1 AF ZDl VHEHZ2 O-3//-1 Zener diode (HZ20-3) 1 m- AB ZD2 VH EH Z 6 A 2//‘/- 1 Zener diode (HZ6A-2) 1 1 AB ZD20 VHEHZgAl//‘/-1 , Zener diode (HZSA-1) 1 AB 3- 2 HPNLCA 14 5WR F 0 / Control panel frame 1 AK 3- 3 I GMAD i 0 0 5 9WR F 0 ! Display filter 1 AE 3- 4 1 JBTN-A158WRFO 1 Open button 1 AD 3- 5 MSPRC0066WREO Button spring 1 AA 3- 6 PCUS-A0 3 5WRP0 Cushion (T5X22X22) 1 AB 3- 7 DUNTKAO 7 9WRK 0 Key unit assembly 1 AY OVEN PARTS 4- 1 DbVN-0 2 5 1WRY 0 Oven cavity 1 BP 4- 2 GDA i -0 2 6 6WRP 0 Oven supporting plate 1 AF 4- 3 GLEGP0021WREO Foot 2 AB 4- 4 LANGQO 4 2 9WRP 0 Turntable motor mounting plate 1 AE 4- 5 GCbVH 0 2 3 3 WR P 0 Turntable motor cover 1 AE 4- 6 FHNG-0 10 2WRY 0 Upper oven hinge 1 AE 4- 7 FHNG-0 10 3WRY 0 Lower oven hinge 1 AE 4- 8 NTNT-0 0 6 7WR E 0 Turntable tray 1 AR 4- 9 FRGLPAO 0 5WRK0 Turntable roller assembly 1 AR 4- 9A NRbLPAO 0 6WRE0 Turntable roller 3 AE 4-10 NC P L-O 0 3 2 WR F 0 Turntable coupling 1 AE 4-11 PF i LWO 0 3 5WRP 0 Oven lamp filter 1 AB 4-12 PCoVP0342WREO Waveguide cover 1 AE 30

4-17 PSPAY0017WRPO Thermo-spacer 4-18 PCUSUO189YBPO Shading cushion 4-19 PCUSU0506WRPO Magnetron cushion 4-20 PC@iPA051WRFO Sensor cover 3 AA 1 AG 1 AF 1 AC 1 AA 1 AA 1 AB 1 AC DOOR PARTS 5 C Db R F A 0 8 8 WR K 0 ’ Door assembly, complete 1 5- 1 FCOVAA 0 18WRY 0 Door screen 1 5- 2 DDoRF0476WRYO Doorpanel 1 5- 3 PSLDM0359WREO Ferrite 1 5- 4 MS P R T 0 0 5 9 WR E 0 Latch spring 1 5- 5 MLEVF0288WRPO Joint lever 1 5- 6 LSTPPO 0 6 7WRF 0 Upper latch head 1 5- 7 LSTPPO 0 6 8WRF 0 Lower latch head 1 5- 8 MLEVP0095WRFO Door lever 1 5- 9 LP iN-0003YBM0 Latch shaft 3 5-10 5-11 _-- ~ PSHEKA002WREO Door sheet PTPEHAOO lWRE0 , Door tape 7 24 6-l % 6-2 6- 3 6- 4 6- 5 6- 6 6- 7 6- 8 6- 9 6-10 - L QW-QZA004WREO High voltage wire A QW-QZO 13 lWRE0 High voltage wire B FW-VZA173WREO Main wire harness LHLDWQ004YBEO Wire holder (Puree lock “L”) TCADC0253WRRO Cook book TiNSEA164WRRO Operation manual TLABS0057WRRO Fuse label TCAUH0114WRRO Caution label TSPCNA295WRRO Name plate FW-VZA135WREO Sensor harness MISCELLANEOUS 1 AG 1 AB BL AZ BB AT AC AB AB AC AB AA AE AE AU AA AR AF AA AC AB AG SCREWS, NUTS, WASHERS AND RINGS 7- 1 LX-B Z 0 14 1 WR E 0 Screw I monitor switch lever mtg 1 AA Note : The parts marked “%” are used in voltage more than 250V. 31

0 1 8 6WR E 0 Screw ; rectifier, capacitor holder, earth wire (for control 6 AA unit), transformer (for control unit), monitor resistor and turntable motor cover mtg I 7- 3 j LX-BZ0194WREO Screw; open plate mtg 1 1 AB 7- 4 ‘XOTSC40P12000 Screw;outercasecabinet mtg 6 I AA / 7- 5 ; L X-CZ 0 0 4 7WR E 0 Screw ; control panel back plate and unit chassis mtg / LX-EZA 0 0 4WR E 0 1 8 AA 7- 6 Screw ; upper and lower latch hook mtg ) 2 AA 7- 7 LX-E Z 0 0 4 6WR E 0 Screw ; outer case cabinet mtg 2 AB 7- 8 XB P SD 4 0 P 0 4 0 0 0 Screw ; turntable motor mounting plate mtg / 3 AA 7- 9 1 XBPSD40P25000 Screw; fan motor mtg 2 AA 7-10 ~XBPSD5OPlOKOO Screw;magnetronmtg I 7-11 j X B P SD 6 0 P 1 2 K S 0 Screw ; power transformer mtg ! : 1:: / 7-12 j X BT SD4 0 P 2 5 0 0 0 Screw ; cord anchorage mtg / l ’ AA 1 7-13 I XC P SD 5 0 P 1 6 K S 0 Screw ; upper and lower oven hinge mtg ’ 4 AA I 7-14 1 XCT SD 4 0 P 1 2 0 0 0 Screw ; oven supporting plate, unit chassis and latch hook 1 4 AA I ! (wper) mtg 7-15 i XFPSD4 OPO 8 0 0 0 Screw ; turntable motor mtg 2 j AA 7-16 ’ XHPSD30P12XSO Screw; control unit mtg 3 1 AA 7-17 ; XTPSD4 0 P 12 0 0 0 Screw ; key unit assembly mtg 2 / AA 7-18 jXFTSD40P08000, Screw;magnetronairductmtg 1 I 7-19 XTTSD4 0 P 12 0 0 0 1 AA 1 Screw ; chassis support mtg 1 j AA 7-20 ; XTTSD4 0 P 12TVO Screw ; chassis support mtg f 1 AA i I 7-21 XTT SD4 0 P 1 6 0 0 0 Screw ; control panel frame mtg / 1 I AA 7-22 I XFPSD3OPlOOOO Screw; fuse holder 1 AA 7-23 / XN E SD 4 0 -3 2 0 0 0 Nut ; fan motor, cord anchorage and transformer (for 4 AA I I I control unit) mtg 7-24 i XWWS D 6 0 - 0 8 0 0 0 Washer ; transformer power mtg 1 / AA 7-25 / X R S S P 1 2- 0 4 0 0 0 s Ring ; turntable coupling mtg 1 AA 7-26 XWH E Z 1 2 - 0 5 3 0 0 Ring ; turntable coupling mtg / 1 AA 7-27 i XFPSD4 OPO 8K0 0 Screw ; earthing i 1 BAA 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 32

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R-7370 1 2 3 4 I 5 I 6 DOOR PARTS MISCELLANEOUS (6-lJl n rl I, 1 IJ 1) F 6-l P 0 6-3 I 0 6-4 I ;1; G 11.5$ c C D E H 1 1 I 2 I 3 4 5 I 6 35