SERVICE MANUAL SHARP SHARPCORPORATION CONVECTION TAME OF CONTENTS S9706R8580J// PRECAUTIONS... INSIDE FRONT COVER

Transcription

1 SHARP SERVCE MANUAL S9706R8580J// CONVECTON MCROWAVE OVEN TAME OF CONTENTS Page PRECAUTONS... NSDE FRONT COVER FOREWORD... THUMB NDEX... PRODUCT DESCRlPTlON... 2 OPERATON... 4 SERVlClNG... TOUCH CONTROL PANEL ASSEMBLY COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE MCROWAVE MEASUREMENT PROCEDURE PCTORAL DAGRAM CONTROL PANEL CiRCUlT PRlNTED WRNG BOARD PARTS LST PACKNG AND ACCESSORES SHARPCORPORATON

2 R SERVCE MANUAL SHARP PRODUCT DESCRPTON CONVECTON MCROWAVE OVEN R-8580 FOREWORD This Manual has been prepared to provide Sharp Corp. Service Personnel with complete Operation and Service nformation for the SHARP CONVECTON MCROWAVE oven, R t is recommended that service personnel carefully study the entire text of this manual so they will be qualified to render satisfactory customer service. Check interlock switches and door seal carefully. Special attention should be given to avoid electrical shock and microwave radiation hazard. CAUTON MCROWAVE RADATON (RD3602U) 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. Note( Parts List) : The parts marked,,+ are used in voltage more than 25OV. (RD36202U) SHARPCORPORATK)N OSAKA, JAPAN (RD3720 U)

3 R-8580 PRODUCT DESCRPTON SPECFCATON TEM Power Requirements Power Consumption Power Output Convection Heater Power Output Case Dimensions Cooking Cavity Dimensions Control Complement Set Weight 240 Volts 50 Hertz Single phase, 3 wire earthed 4OOW (Microwave) 600W (Convection) DESCRPTON 700 watts normal of RF microwave energy (2 liter water load) Operating frequency of 2450M Hz.500 Watts Width 627mm Height 407mm Depth 500mm Width 395mm Height 253mm Depth 422mm Touch Control System Clock( :00-2:59 ) Timer (0-99 min. 99sec. ) Microwave Power for Variable Cooking Repetition Rate; HGH... Full power throughout the cooking time MED HGH...*... approx. 70% of Full Power MED...*...,.,... approx. 50% of Full Power MED LOW (DEFROST)... approx. 30% of Full Power LOW,...,...* approx. 0% of Full Power HOLD.,...*... No power throughout the cooking time Convection Temperature Contro i Range; 40 C C AUTO START COOKNG NSTANT COOKNG EASY DEFROST COOKNG CONVECTON COOKNG SENSOR COOKNG AUTO MATC MX COOKNG COMPU COOKNG Approx. 3.O kg

4 R-8580 Auto-TouchTM Control Panel Touch to select sensor cook mode,&&:::c::p: Touch to select Compu Cook mode - Fresh vegetables 2 - Frozen vegetables 3 - Baked potatoes 4 - Frozen dinners 5 - Bacon 6 - Chicken preces 7 - Fish fillets 6 - Rice 8 Pasta 9 - Cake 0 - Reheat -Roast beef/lamb 2 - Roast pork 3 - Roast chrcken 4 - Roast turkey 5 -Roast dmner 6 - Mixed grill 7 -Grilled chicken 6 - Bread loaves 9 -Cake layers 0 - Biscuits -..EASY DEFROST PAD Touch to defrost meat by weight only entering NSTANT COOK PAD Touch once to cook for minute at HGH or increase by minute mult :iples each time this pad is touched during HGH/VARABLE cooking. NUMBER AND TEMPERATURE PADS Touch to enter cooking times, clock time, convection temperature or to select the Sensor or Compu Cook categories. CONVECTON COOKNG FUNCTON PADS Touch to cook for each function 6 80 C i 7 200% 4 / VARABLE COOKNG CONTROL PADS Touch to select microwave power setting. f not touched, HGH is automatically selected. Touch to select food doneness setting for Compu Cook. f not touched, Med Done is automatically selected. TMER/HOLD PAD Touch to set minute timer or HOLD function -AUTO START/CLOCK PAD Touch to set clock or auto start time TMER AUTO START HOLD CLOCK,---STOP/CLEAR PAD Touch to erase during programming. Touch once to stop operation of oven during cooking;, touch twice to cancel cooking Touch to start oven after setting programme.

5 OPERATON DESCRPTON OF OPERATNG SEQUENCE The following is a description of component functions during oven operation. (RD70 U) OFF CONDTON Closing the door activates both door interlock switches: upper latch switch, lower latch switch and stop switch. (n this condition, the monitor switch contacts are opened.) When oven is plugged in, 240 volts A.C. is supplied to the relay unit. (Figure O-l).. The display will show flashing 88:88. To set any program or set the clock;- you must first touch the STOP/CLEAR pad. The display will clear, and :00 will appear and count up every minute. Note: When the door is opened, the oven lamp comes 2. A si;al is input to the control unit, energizing the coil of shut-off relay (RY6). RY6 contacts close, completing a circuit to the damper motor. The damper motor now operates moving the damper to the open position, thereby closing the contacts of the damper switch inputs a signal to the control unit. The coil of relay RY6 is de-energized, opening its contacts, thereby turning off the damper motor. (RD7207U) COOKNG CONDTON HGH COOKNG Program desired cooking time and Variable Cooking Control by touching the NUMBER pads and the HGH pad of the Variable Cooking Control. When the START pad is touched, the following operations occur:. The contacts of relays are closed and components connected to the relays are turned on as follows. (For details, refer to Figure O-2) RELAY CONNECTED COMPONENTS RY- power transformer RY-2 oven lamp/turntable motor RY-3 convection motor RY-4 convection heater RY-5 RY-6 fan motor damper motor 240 volts A.C. is supplied to the primary winding of the power transformer and is converted to about 3.3 volts A.C. output on the filament winding, and approximately 2043 volts A.C. on the high voltage winding. The filament winding voltage heats the magnetron filament and the H.V. winding voltage is sent to a voltage doubler circuit. The microwave energy produced by the magnetron is channeled through the waveguide into the cavity feed-box, and then into the cavity where the food is placed to be cooked. 5. Upon completion of the cooking time, the power transformer, oven lamp, etc. are turned off, and the generation of microwave energy is stopped. The oven will revert to the OFF condition. 6. When the door is opened during a cook cycle, monitor switch, upper latch switch, lower latch switch and stop switch. are activated with the following results. The circuits to the turntable motor, the cooling fan motor, and the high voltage components are deenergized, the oven lamp remains on, and the digital readout displays the time still remaining in the cook cycle when the door was opened. 7. The monitor switch is electrically monitoring the operation of the upper latch switch and is mechanically associated with the door so that it will function in the following sequence. () When the door opens from a closed position, the upper latch switch and lower latch switch open their contacts, and then the monitor switch contacts close. (2) When the door is closed from the open position, the monitor switch contacts first open, and then the contacts of the upper latch switch and lower latch switch close. f the common and normal open contacts of upper latch switch fail with their contacts closed when the door is opened, the closing of the monitor switch contacts will form a short circuit through the fuse and upper latch switch, causing the monitor fuse to blow. MED HGH, MED, MED LOW (DEFROST), LOW, HOLD COOKNG When Variable Cooking Power is programed, the 240 volts A.C. is supplied to the power transformer intermittently through the contacts of relay( RY-2) which is operated by the control unit within a 32 second time base. Microwave power operation is as follows: VAR-MODE ON TME OFF TME HGH 32 sec. 0 sec. (00% power) MED HGH 24 sec. 8 sec. (approx. 70% power) MED 8 sec. 4 sec. (approx. 50% power) MED LOW (DEFROST) 2 sec. 20 sec. (approx. 30% power) LOW 6 sec. 26 sec. (approx. 0% power) HOLD 0 sec. 32 sec. (0% power) Note: The ON/OFF time ratio does not correspond with the percentage of microwave power, because approx. 2 seconds are needed for heating of the magnetron filament. (RD740 U)

6 R CONVECTON COOKNG CONDTON PREHEATNG CONDTON Program desired convection temperature by touching the CONVECTON pad and the temp. pad. When the START pad is touched, the following operations occur:. The coil of shut-off relays (RY2, RY3 and RY5) are energized, the oven lamp, cooling fan motor, turntable motor and convection motor are turned 2. y:k coil of relay (RY6) is energized by the CPU unit, The damper is moved to the closed position, opening the damper switch contacts. The opening of the damper switch contacts sends a signal to the LS on the CPU unit de-energizing the relay (RY6) and opening the circuit to the damper motor. 3. The coil of heater relay (RY4) is energized by the CPU unit and the main supply voltage is added to the convection heater. 4. When the oven temperature reaches the selected preheat temperature, the following operations occur: 4-l. The heater relay (RY4) is de-energized by the CPU unit temperature circuit and thermistor, opening the circuit to the convection heater The oven will continue to function for 5 minutes, turning the convection heater on and off, as needed to maintain the selected preheat temperature. The oven will shut-down completely after 5 minutes. CONVECTON COOKNG CONDTON When the preheat temperature is reached, a beep signal will sound indicating that the holding temperature has been reached in the oven cavity. Open the door and place the food to be cooked in the oven. Program desired cooking time and convection temperature by touching the NUMBER pad, CONVECTON pad and Temperature pad. When the START pad is touched, the following operations occur:. The numbers of the digital readout. start the count down to zero. 2. The oven lamp, turntable motor, cooling fan motor and convection motor are energized. 3. Heater relay (RY4) is energized (if the cavity temperature is lower than the selected temperature) and the main supply voltage is applied to the convection heater to return to the selected cooking 4. temperature. Upon completion of the cooking time, the audible signal will sound, and oven lamp, turntable motor, cooling fan motor and convection motor are de-energized. At the end of the convection cycle, if the cavity air temperature is above 8 OC., the circuit to RY5 will be maintained (by the thermistor circuit) to continue operation of the cooling fan motor until the temperature drops below 8 OC., at which time the relay will be de-energized, turning off the fan motor. Relay RY3 will however, open as soon as the convection cycle has ended, turning off the convection fan motor.this will now cool and allow the damper door to open. 5. At the end of the convection cook cycle, shut-off relay (RY6) is energized turning on- the damper motor. The damper is returned to the open position, closing the damper switch contacts which send a signal to the control unit, de-energizing shut-off relay (RY6). AUTOMATC MX COOKNG CONDTON Program desired cooking time and temperature by touching the number pads and the LOW MX/BAKE or HGH MX/ROAST pad When the START pad is touched, the following operations occur:. The numbers of the digital readout start the count down to zero. 2. The shut-off relay (RY2, RY3 and RY5) are energized, turning on the oven lamp, turntable motor, and cooling fan motor. 3. The shut-off relay (RY6) is energized. The damper door is closed from the open position. 4. The heater relay (RY4) is energized, adding the mains supply voltage to the convection heater. 5. Now, the oven is in the convection cooking condition. 6. When the oven temperature reaches the selected temperature, the following operations occur: 6-l. The power supply voltages is added to the convection heater and power transformer alternately The convection heater operates through the heater relay (RY4) contacts and the power transformer operates through the cook relay (RY ) contacts These are operated by the CPU unit to supply alternately within a 32 second time base, convection heat and microwave energy. The relationship between the convection wave power operations are as follows. and micro- Note: The ON and OFF time ratio does not correspond with the percentage of microwave power, because approx. 2 seconds are needed for heating of the magnetron filament. CONVECJ ON t im OFF &gjggg& r 32~ HGH MX -ROAST i MCROWAVE POWER - Appmx. 0% CONVECTON TEMPERATURE - leo C MCROWAVE POWER - A6wrcuc. 30% CONVECTON TEMPERATURE -200%

7 R-8580 Note: During alternate Microwave/Convection operation, the convection heater is energized only if the cavity temperature drops below the set temperature. SENSOR COOKNG CONDTON Using the SENSOR COOK function, the foods are cooked without figuring time, power level or quantity. When the oven senses enough steam from the food, it relays the information to its microprocessor which will calculate the remaining cooking time and power level needed for best results. When the food is cooked, water vapor is developed. The sensor senses the vapor and its resistance increases gradually. When the resistance reaches the value set according to the menu, supplementary cooking is started. The time of supplementary cooking is.determined by experiment with each food category and inputted into the LS. An example of how sensor works:. Broccoli at room temperature. Vapor is emitted very slowly. 2. Heat broccoli. Moisture and humidity is emitted rapidly. You can smell the aroma as it cooks. 3. Sensor detects moisture and humidity and calculates cooking time and variable power. Cooking Sequence.. Touch SENSOR COOK pad. NOTE:The oven should not be operated on SEN- SOR COOK immediately after plugging in the unit. Wait five minutes before cooking on SENSOR COOK. 2. Select desired Sensor setting. 3. Touch START pad. The coil of shut-off relays(ry2,ry5) are energized, the oven lamp and cooling fan motor are turned on, but the power transformer is not turned on, 4. After about 6 seconds, the cook relay (RY) is energized. The power transformer is turned on, microwave energy is produced and first stage is started. The 6 seconds is the cooling time required to remove any vapor from the oven cavity and sensor. NOTE: During this first stage, do not open the door or touch STOP/CLEAR pad. 5. When the sensor detects the vapor emitted from the food, the display switches over to the remaining cooking time and the timer counts down to zero. At this time, the door may be opened to stir food, turn it or season, etc. 6. When the timer reaches zero, an audible signal sounds. The shut-off relay and cook relay are de-energized and the power transformer, oven lamp, etc. are turned off, 7. Opening the door or touching the STOP/CLEAR pad, the time of day will reappear on the display and the oven will revert to an OFF condition. COMPU COOK COMPU COOK will automatically compute the oven temperature, microwave power and cooking time for baking, roasting and broiling. Set the desired program by touching the COMPU COOK pad, and number pad. Enter the weight by touching the Number pads When the START pad is touched, the following operations occur:. The COOK indicator will light and the Convection Fan Symbol will rotate. 2. The cooking time will appear on the display and start counting down to zero. The cooking time is adjusted automatically according to the weight of the food. 3. The shut-off relays (RY2, RY3, RY4 and RY5) are energized, turning on the oven lamp, turntable motor, cooling fan motor and convection motor. The power supply voltage is added to the convection heater. 4. Now, the oven is in the convection cooking mode. 5. When the oven temperature has reached the programmed convection temperature, the oven goes into the programmed cooking mode. 6. At the end of the COMPU COOK cycle, the damper is returned to the open position and the oven will go to the off condition. The cooling fan will remain on until the oven has cooled. EASY DEFROST COOKNG The EASY DEFROST key is a special function key to defrost meats and poultry faster and better. EASY DEFROST key has 4 defrost stages. EASY DEFROST automatically defrosts roast beef, etc. When EASY DEFROST is selected and the food weight is entered by using the number pads, the oven will cook according to the special cooking sequence.

8 240V-50Hz G-4 MBA AC CORD CONNECTON BRN BROWN BLU : BLUE G-Y GREEN AND YELLOW STRPE 7 : SECTONAL AREA OF l.omm MN. MONTOR RESSTOR O.B/2OW MON,TOR SW,TCH OVEN LAMP FAN MOTOR n RELAY-UNT A-3 - TEMP. FUSE 42 C AC CORD CONNECTON BRN BROWN BLU BLUE G-Y GREEN AND YELLOW STRPE /7 SECTONAL AREA OF l.omm MN, RELAY-UNT OVEN MONTOR RESSTOR D.B/2DW MONTOR SWTCH LAMP -_- i TEMP. FUSE 42 C DOOR CLOSE0 LOWER LATCH SWTCH UPPER LATCH SWTCH NC? SENSOR COOKNG NOTE CONDTON DOOR CLOSED 2 SENSOR COOK PAD TOUCHED 3 START PAD LOWER -. AT -.. SWTCH d ^-^^ w. +A-7 RW A-5 l-6 A RV6 c UPPER LATCH SWTCH NC HGH COOKNG DAMPER MOTOR - CONVECTON HEATER TURNTABLE MOTOR DOOR CLOSED 2 COOKNG TME PROGRAMMED 3 VARABLE COOKNG CONVECTON%EATER - ; POWER TRANSFORMER POWER TRANSFORMER t MAGNETRON A MAGNETRON RECTFER, HGH VOLTAGE RECTFER HGH VOLTAGE RECTFER Figure O-l. Oven Schematic-OFF Condition Figure O-2. Oven Schematic-High and Sensor Cooking Condition

9 R V-50Hz MONTOR RESSTOR 0.8/20W MONTOR SWTCH a//o OVEN LAMP TEMP. FUSE 42 C FAN MOTOR AC CORD BRN BLU : BROWN : BLUE CONNECTON G-Y : GREEN AND YELLOW STRPE 7 : SECTONAL AREA OF l.omm MN. LOWER LATCH SWTCH UPPER LATCH SWTCH NC SCHEMATC NOTE: CONDTON OF OVEN. DOOR CLOSED 2. CONVECTON PAD TOUCHED 3. DESRED TEMP. PAD TOUCHED 4. START PAD TOUCHED 4 B CON ECTlON%ATER POWER TRANSFORMER RECTFER j! L i CAPACTOR.3/i AC2200V MAGNETRON 4 HGH VOLTAGE RECTFER Figure O-3. Oven Schematic-Convection Cooking Condition 8

10 R DESCRPTON AND FUNCTON OF COMPONENTS THERMSTOR The thermistor is a negative temperature coefficient type. The temperature in the oven cavity is detected through the resistance of the thermistor, and then the CPU unit causes the heater relay to operate, thus the current to the convection heater is turned ON/OFF. OVEN THERMAL CUT-OUT The oven thermal cut-out located on the bottom side of the thermal protection plate is designed to prevent damage to the convection heater unit if an overheated condition develops in the tube due to cooling fan failure, obstructed air ducts, dirty or blocked air intake, etc. Under normal operation, the oven thermal cut-out remains closed. However, when abnormally high temperatures are reached within the heater unit, the oven thermal cut-out will open, causing the oven to shut down. When the oven has cooled temperature, the oven thermal cut-out closes. MONTOR SWTCH The monitor switch is mounted on the upper latch hook. t is activated (the contacts opened) by the upper latch head when the door is closed. The switch is intended to render the oven inoperative by means of blowning the fuse when the contacts of the common and normal open contacts of upper latch switch fail to open when the door is opened. Functions:. When the door is opened, the monitor switch contacts close (to the ON condition) due to their being normally closed. At this time the the common and normal open contacts of upper latch switch are in the OFF condition (contacts open) due to their being normally open contacts switch. 2. As the door goes to a closed position, the monitor switch contacts are first opened and then the common and normal open contacts of upper latch switch close. (On opening the door, each of these switches operate inversely.) 3. f the door is opened during cooking, and the common and normal open contacts of upper latch switch fail to open, the monitor fuse blows simultaneously with closing of the monitor switch contacts. CAUTON:BEFORE REPLACNG A BLOWN FUSE TEST THE UPPER LATCH SWTCH AND MONTOR SWTCH FOR PROPER OPERATON.(REFER TO CHAPTER TEST PROCEDURE ). AFTER REPLACNG FUSE ALSO REPLACE MONTOR SWTCH. STOP SWTCH The stop switch is activated by the lower latch head. When the door is opened while the oven is in cook cycle, the stop switch contacts open to de-energize the relay(ry-l,ry-2,ry-3,ry-4,ry-5). Then the cook cycle is stopped. UPPER AND LOWER LATCH SWTCHES The lower latch switch is mounted in the lower latch hook and the upper latch switch is mounted in the upper latch hook. They are activated by the latch heads on the door. When the door is opened, the switches interrupt the crrcuit to all components except CPU unit and relay unit and oven lamp. A cook cycle cannot take place until the door is firmly closed thereby activating both interlock switches. A P UPPER LATCH HOOK Figure D-l. Upper Latch Switch, Lower Latch Switch, Monitor Switch and Stop Switch

11 R-8580 CONVECTON HEATER Microwave Cooking: The convection heater is located at the left side of the Damper is in the open position, because a portion of oven cavity. t is intended to heat air driven by the cooling air is channeled through the cavity to remove convection fan. The heated air is kept in the oven and steam and vapors given off from the heating foods. force-circulated and reheated by the convection heater. t is then exhausted at the top of the oven cavity into a condensation compartment. CONVECTON COOKNG SYSTEM This oven is designed with a hot air heating system where food is not directly heated by the convection heater, but is heated by forced circulation of the hot air produced by the convection heater. The air heated by the convection heater is circulated through the convection passage provided on the outer casing of the oven cavity by means of the convection fan which is driven by the convection motor. t then enters the inside of the oven through the vent holes provided on the left side of the oven. Next,the hot air heats the food on the turntable and leaves the oven cavity through the vent in the oven cavity left side wall. Without leaving the oven, this hot air is reheated by the convection heater, passes through the convection passage and enters the inside of the oven cavity again, in a continuing cycle. n this way, the hot air circulates inside the oven cavity to raise its temperature and, at the same time, comes into contact with the food being cooked. When the temperature inside the oven cavity reaches the selected temperature, the convection heater is de-energized. When the temperature inside the oven cavity drops below the selected temperature, the convection heater is energized again. n this way, the inside of the oven cavity is maintained at approximately the selected temperature. When the convection time reaches 0, the convection heater is deenergzed and the convection fan stops operating and the oven shutts off. Upon completion of the cooking time, the audible signal will sound, and oven lamp, turntable motor, cooling fan motor and convection motor are de-energized. At the end of the convection cycle, if the cavity air temperature is above 8 OC., the circuit to RY5 will be maintained (by the thermistor circuit) to continue operation of the cooling fan motor until the temperature drops below 8 OC., at which time the relay will be de-energized, turning off the fan motor. Relay RY3 will however, open as soon as the convection cycle has ended, turning off the convection fan motor.this will now cool and allow the damper door to open. Convection Cooking: Damper is in the closed position, so that no hot air will be allowed to leak out the oven cavity. Damper Operation, When power supply cord is plugged in: l-l. When power supply cord is plugged in, a signal is sensed in the control unit, and operates shut-off relay (RY6). -2. Contacts of shut-off relay (RY6) close, the damper motor is energized, opening the damper door. -3. When the damper is moved to the open position by the damper cam dampe switch is closed (ON position). -4. The signal of damper switch is re-sensed in the control unit and shut-off relay (RY6) is turned off. -5. The 240 volts A.C. to the damper motor is stopped and the motor turns off. 2. When oven is microwave cooking: Damper is in the open position. 3. When oven is convection cooking: 3-l. Damper motor is energized by touching the convection, temperature and START pads When damper is in the closed position (damper switch is OFF), its signal is sensed by the control unit, and shut-off relay (RY6) is de-energized The damper is held in the closed position during the convection cooking operation At the end of the convection cooking, shut-off relay (RY6) is energized, and the damper is returned to the open position. NOTE: f the damper door is not in the proper position, closed durin convection or open durning microwave, the control unit will stop oven operation after minute. DAMPER OPEN-CLOSE MECHANSM Usually, the damper is in the open position except during convection cooking. Damper position is set automatically by damper motor, damper switch, motor cam and damper shaft. These components are operated by a signal that judges if microwave cooking or convection cooking operation is selected by the CPU unit. Cooking Mode Operation of Damper Microwave cooking OPEN Convection cooking CLOSE Sensor cooking OPEN Automatic mix cooking CLOSE Grill cooking CLOSE Slow cooking CLOSE 0

12 SERVCNG TROUBLESHOOTNG GUDE When troubleshooting the microwave oven, it is helpfull 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. MPORTANT: lf the oven becomes inoperative because of a blown fuse in the monitor switch and upper latch switch circuit, check the monitor switch and upper latch switch before replacing the fuse. f the fuse is replaced, the monitor switch should be replaced at same time. (RD8 ll OZU) PROBLEM POSSBLE CAUSE TEST PROCEDURE OR CORRECTON OFF CONDJTON Home fuse blows when power cord is plugged into wall receptacle. Fuse blows when power cord is plugged into wall receptacle. Shorted wire in power cord or wire harness. Shorted wire in power cord or wire harness. Defective monitor switch. Procedure F. Replace cord or check wiring. Replace power cord or check and repair harness. 88:88 do not appear in display No power at outlet. Check home fuse. when power cord is first plugged Blown fuse. Procedure G. into wall outlet. Blown magnetron temp. fuse. Procedure H. Defective thermal cut-out. Procedure. Open wire in power cord, wiring harness, or wrrrng between control panel assembly units. Replace or repair wiring. Defective CPU unit. Procedure 0. Defective relay unit. Procedure N. Display does not operate properly Defective key unit. Procedure P. when STOP/CLEAR key is Defective CPU unit. Procedure 0. touched. (B uzzer should sound and time of day should appear in Defective relay unit. Procedure N. display.) Defective stop switch. Procedure E. Oven lamp does not light with No power in home. Check wall outlet. door opened., Open wire in power cord or wire harness., Replace same or repair wir- rng. Defective oven lamp. Replace. Defective upper latch switch. -* Procedure E. Blow fuse. Procedure G. Defective thermal cut-out. Procedure. Defective magnetron temp. fuse. Procedure H. Open or loose wire connection to the Check wiring. above components.

13 R PROBLEM POSSBLE CAUSE TEST PROCEDURE OR CORRECTON COOKNG CONDTON Oven lamp does not light in cook Defective shut-off relay (RY2) on relay Procedure N. cycle. unit. (Does light when door is opened) Defective CPU unit. Procedure 0. Oven lamp does not light at all. Burned out bulb. Replace Open wiring of oven lamp. Check and repair wiring Oven lamp lights, but turntable Open or loose wiring to turntable motor. Check and repair wiring motor does not operate. Defective turntable motor. Replace Turntable motor operates normally Defective cooling fan motor. Replace. but cooling fan motor does not Defective shut-off relay (RY5) on relay Procedure N. operate unit. Open or loose wiring to fan motor Check and repair wiring MCROWAVE Oven does not go into a cook cy- Upper latch switch and/or lower latch Procedure E. cle when START pad is touched. switch defective or out adjustment. Defective cook relay (RY ) on relay unit. Procedure N. Defective CPU unit. Procedure 0. Defective key unit. Procedure P. Open or loose wiring to above compo- Check and repair wiring nents. Oven seems to be operating but Defective magnetron. Procedure A. little or no heat is produced in Defective cook relay (RY ) on relay unit. Procedure N. oven load.( Food incompletely Defective power transformer. Procedure B. cooked or not cooked at all at end Defective high voltage rectifier. Procedure C. of cook cycle.) Defective high voltage capacitor. Procedure 0. Defective CPU unit. Procedure 0. Open or loose wiring to above compo- Check and repair wiring nents. Oven goes into a cook cycle but Turntable motor does not operate. Replace turntable motor or extremely uneven heating is check and repair wiring. produced in oven load(food). Oven does not cook properly Defective CPU unit. Procedure 0. when programed for MEDUM Defective key unit. Procedure P. etc. cooking powers. Open or loose wiring to above compo- Check and repair wiring (Operates properly on HGH) nents. Oven does not cook properly Defective EASY DEFROST function. Refer to EASY DEFROST when programed in EASY DE- section in operation manual FROST cooking mode. and check CPU unit. 2

14 R PROBLEM POSSBLE CAUSE TEST PROCEDURE OR CORRECTON CONVECTON r CONV indicator light but oven does not go into a cook cycle when START pad is touched. CONV indicator lights, but heating element does not heat. Temperature in the oven cavity is lower or higher than preset. Lower than preset temperature. Cooling fan motor, turntable motor and oven lamp run intermitantly or all the time. Convection cycle runs 3 minutes then shuts down. Defective heater relay(ry4) on relay unit. Procedure N. Defective key unit. Procedure P. Defective thermistor. procedure K. Open wiring in circuit to above components. Check and repair wiring. Defective convection heater. Procedure J. Defective heater relay(ry4) on relay unit. Procedure N. Defective CPU unit. Procedure 0. Open or loose wire connection to the Check and repair wiring. above components. Defective convection heater. Procedure J. Defective CPU unit. Procedure 0. Defective convection motor. Replace motor. Defective thermistor. Procedure K. Defective cooling fan motor. Replace fan motor. Defective dumper motor. Procedure L. Defective drive mechanism of convection Check. fan. Low power supply voltage. Check voltage. Thermistor shorted. Procedure K. Thermistor open. Procedure K. SENSOR Oven is in the sensor cooking AH sensor open and/or short. Procedure 0. condition but AH sensor does not Defective CPU unit. Procedure 0. end stage or does not stop 0 pen or loose wire connection to the Check and repair wiring. cooking cycle or the oven stops above components. soon. AH sensor assembly and/or steam duct Check and repair them. are not re-installed correctry. 3

15 R-8580 TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST MAGNETRON ASSEMBLY TEST DSCHARGE THE HGH VOLTAGE CAPACTOR BEFORE TOUCHNG ANY OVEN COMPO- NENTS OR WRNG. To test for an open filament, isolate the magnetron from the high voltage circuit. A continuity check across the magnetron filament leads should indicate less than ohm. To test for a shorted magnetron, connect the ohmmeter leads between the magnetron filament leads and chassis ground. This test should indicate an infinite resistance. f there is little or no resistance, the magnetron is grounded and must be replaced. Power output of the magnetron can be measured by performing a water temperature rise test. This test should only be used if above rests do not indicate a faulty magnetron and there is no defect in the following components or wiring: high voltage rectifier, rectifier, high voltage capacitor, and power transformer. MCROWAVE OUTPUT POWER Microwave output power from the magnetron can be measured by way of substitution, i.e. it can be measured by using water load how much it can be absorbed by the water load. To measure the microwave output power in the microwave oven, the relation of calorie and watt is used. When P(W) heating works for t(second), approximately P x t/4.2 calorie is generated. On the other hand, if the temperature of the water with V(ml) rises AT ( C) during this microwave heating period, the calorie of the water is V x AT. The formular is as follows; Pxt/4.2=Vx P(W)=4.2xVx AT AT/t Our condition for the water load is as follows: Water load ml, Heating time seconds P=7Ox AT Measuring method;. Put the water load of two (2) litres on the center of the oven shelf. The water load should be arranged in two (2) Pyrex beakers, the size of which is one () litre, and be placed at right and left, side by side, on the oven shelf. 2. Measure the temperature of water before heating and also after heating during 20 seconds by microwave, and calculate the temperature rise. The temperature rise should be the average of temperature differences measured in each beaker. 3. The output power should be calculated as follows. n case the measuring result is not satisfactory, execute the measurement several times and judge the result from the synthetic point of view. Microwave output power should be within + 5% of the nominal one. Calculation of output power; Microwave output power...p(w)=7ox AT(%) AT = ( ATL + ATR) / 2 : average temperature rise ATL = (TL2 - TL), ATR = (TR2 - TR) TL2 : water temperature after heating in left beaker TL : water temperature before heating in left beaker TR2 : water temperature after heating in right beaker TR : water temperature before heating in right beaker Measuring condition; As the microwave output is affected by several conditions, the measurement should be made carefully with following attentions.. nitial temperature of salt water should be 0 + C. Well and quickly stir the water and the temperature measurement should be done immediately after heating. 2. The graduation of thermometer should be scaled by 0. C at minimum and an accurate mercury thermometer is recommended. 4

16 R-8680 TEST PROCEDURES (CONT D) PROCEDURE LETTER COMPONENT TEST 3. Water container should be one () litre beaker made of Pyrex glass and its diameter approximately 2 cm. 4. Room temperature should be around 20 C. 5. Power supply voltage should be specification voltage. POWER TRANSFORMER TEST DSCHARGE THE HGH VOLTAGE CAPACTOR BEFORE TOUCHNG ANY OVEN COMPO- NENTS OR WRNG. Disconnect the primary input terminals and measure the resistance of the transformer with an ohmmeter. Check for continuity of the coils with an ohmmeter. On the R x scale, the resistance of the primary coil should be approx..6 ohm and the resistance of the high voltage coil should be approximately 74 ohms; the resistance of the filament coil should be less than ohm. (HGH VOLTAGES ARE PRESENT TO HGH VOLTAGE TERMNAL, SO DO NOT ATTEMPT TO MEASURE THE FLAMENT AND HGH VOLTAGE.) C HGH VOLTAGE RECTFER AND RECTFER TEST DSCHARGE THE HGH VOLTAGE CAPACTOR BEFORE TOUCHNG ANY OVEN COMPO- NENTS OR WRNG. HGH VOLTAGE RECTFER TEST solate the high voltage rectifier from the circuit. Using the highest ohm scale of the meter read the resistance across the terminals and observe, reverse the leads to the high voltage rectifier terminals and observe meter reading. f a short is indicated in both directions, or if an infinite resistance is read in both directions, the high voltage rectifier is probably defective and should be replaced. D RECTFER TEST solate the rectifier from the circuit. Using the highest ohm scale of the meter, read the resistance across the terminals, reverse the leads to the rectifier terminals and observe meter reading. f an infinite resistance is read in both directions, the rectifier is good. f a short is indicated in either direction, the one is probably defective and should be replaced. HGH VOLTAGE CAPACTOR TEST DSCHARGE THE HGH VOLTAGE CAPACTOR BEFORE TOUCHNG ANY OVEN COMPO- NENTS OR WRNG. E f the capacitor is open, no high voltage will be available to the magnetron. Disconnect input leads and check for short or open, between the terminals using an ohmmeter. Checking with a high ohm scale, if the high voltage capacitor is normal, the meter will indicate continuity for a short time and should indicate approximately OM R once the capacitor is charged. f the above is not the case, check the capacitoi with an ohmmeter to see if it is shorted between the terminals. f it is shorted, replace the capacitor. SWTCH TEST (RD82603U) solate the switch and check the contacts by using an ohmmeter using the following table. f improper operation is indicated, make the necessary switch adjustment or replacement. Table: Switch Connection Connection Common Terminal-Normally Open Terminal Operation (COM) (NO) Plunger released Open circuit Close circuit Plunger pushed Closed circuit Open circuit Common Terminal-Normally Close Terminal (COW (NC) (RD8270U) 5

17 R-8580 TEST PROCEDURES (CONT D) PROCEDURE LETTER COMPONENT TEST MONTOR SWTCH TEST Before performing this test, disconnect oven from power supply and make sure that the upper latch switch is operating properly referring to the above Switch Test Procedure. Disconnect the wire lead from the monitor switch (NC) terminal. Check the monitor switch operation by using the ohmmeter as follows. When the door is open, the meter should indicate a closed circuit. When the monitor switch actuater is pushed by a screw driver through the upper latch hole on the front plate of the oven cavity with the door opened (in this condition the plunger of the monitor switch is pushed in), the meter should indicate an open circuit. f improper operation is indicated, replace the defective switch.. After testing the monitor switch, re-connect the wire lead to the monitor switch (NC) terminal. SCREW. \ UPPER LACCH HOLE G BLOWN FUSE f the fuse in the upper latch-monitor switch circuit is blown when the door is opened, check the upper latch switch and monitor switch according to the Test Procedure for those switches, before replacing the blown fuse. f the fuse is replaced, the monitor switch should be replaced at the same time. f the fuse is blown by improper switch operation, adjust or replace the defective switch, fuse at the same time. Replace the fuse and monitor switch, even if the switches operate normally CAUTON; REPLACEMENT FUSE MUST BE THE LSTED FUSE N PARTS LST. H TEMP. FUSE TEST A continuity check across the temp. fuse terminals should indicate a closed circuit. f the temperature of the magnetron reaches 42 C, the temp. fuse opens. f the temp. fuse has opened, replace the fuse. An open temp. fuse indicates overheating of the magnetron assembly. Check for restricted air flow to the magnetron through the opening in the chassis, especially the cooling duct and tolling fan. THERMAL CUT-OUT. A continuity check across the thermal cut-out terminals should indicate a closed circuit unless the temperature of the thermal cut-out reaches approximately 40 C. The termal cut-out resets automatically at approximately 5 C. f the thermal cut-out has opened under the normal condition, replace the same one is parts list. An open thermal cut-out indicates overheating of the heater unit. Check for restricted air flow to the heater unit through the vent holes of the oven cavity, especially the heater duct and convection fan 6

18 R TEST PROCEDURES (CONT D) \ PROCEDURE LETTER COMPONENT TEST CONVECTON HEATER TEST Make sure the convection heater is fully cooled and test as follows; a. Disconnect wire leads and measure the resistance with an ohmmeter. On the R x scale, the resistance between the convection heater terminals should be approximately 38 ohms. b. Disconnect wire leads and measure the insulation resistance with 500V - OOM R insulation resistance meter. The insulation resistance between convection heater terminal and cavity should be more than 0.5M R. K THERMSTOR TEST Disconnect connector-e from the control unit. Measure the resistance of the thermistor with an ohmmeter. Connect the ohmmeter leads to Pin No s E-3 and E-4. Room Temp. Resistance 20 C - 30 C Approx. 350 n - 55 S2 f the meter does not indicate above resistance, replace the thermistor. L DAMPER MOTOR TEST When the power cord is plugged into the wall receptacle, and 240 volts A.C. is supplied to the damper motor the motor operates until the damper is opened and the damper switch closes. Then the damper motor stops operation. f the damper motor does not operate, check for input voltage by A.C. volt-meter at the motor.. Disconnect the power cord from the wall receptacle. 2. Disconnect the wire leads of motor and connect the meter leads to the wire leads of main wire harness. 3. Reconnect the power cord into the wall receptacle. f 240 volts A.C. is indicated at the wire leads, replace the motor. Not indicated, check the wire harness and the relay unit. M DAMPER SWTCH TEST (RD82EOl U) Disconnect the wire leads from the switch terminals and connect ohmmeter leads to the common (COM) and normally open (NO) terminals of the switch.. When switch actuator is pushed by the damper motor cam, the meter should indicate a closed circuit. 2. When the power cord is plugged into the wall receptacle, the damper motor operates and damper cam starts to rotate. The switch actuator is released the meter should indicate an open circuit. f improper operation is indicated, replace the damper switch. (RD82702U) 7

19 R-8580 TEST PROCEDURES (CONT O) PROCEDURE LETTER COMPONENT TEST N RELAY UNT TEST The relay unit consists of circuits including the shut-off relays, buzzer, transformer, etc. Plug power cord into wall receptacle 88:88 will be flashing in the display. Remove the outer case and check voltage between Pin Nos. and 3 of the 6-pin connector (A) on the relay unit with an A.C. voltmeter. The meter should indicate 240 volts, if not check oven circuit. Shut-off, Cook and Heater Relay Test These relays are operated by D.C. voltage. Check voltage at the relay coil with a D.C. voltmeter during the microwave or convection cooking operation. DC. voltage indicated.,... Defective relay. DC. voltage not indicated...check diode which is connected to the relay coil. f diode is good, control unit is defective. RELAY SYMBOL RYl (COOK) Approx. 4 V. D. C. RY2 Approx. 4 V.D.C. RY3 Approx. 4 V.D.C. RY4 (HEATER) Approx. 4 V.D.C. RY5 Approx. 4 V. D. C. RY6 Aoorox. 4 V.D.C. OPERATONAL CONNECTED COMPONENTS VOLTAGE Power transformer Oven lamp/turntable Convection motor Heating element Cooling fan motor DamDer motor motor (RD82R02U) 8

20 TEST PROCEDURES (CONT O) PROCEDURE LETTER COMPONENT TEST TOUCH CONTROL PANEL ASSEMBLY TEST The touch control panel consists of circuits including semiconductors such as LS, Cs, etc. Therefore, unlike conventional microwave ovens, proper maintenance cannot be performed with only a voltmeter and ohmmeter. n this service manual, the touch control panel assembly is divided into three units Control Unit, Key Unit and Relay Unit and troubleshooting by unit replacement is described according to the symptoms indicated.. Key Unit. The following symptoms indicate a defective key unit. Replace the key unit. a) When touching the pads, a certain pad produces no signal dt all. b) When touching a number pad, two figures or more are displayed. c) When touching the pads, sometimes a pad produces no signal. 2. Control Unit The following symptoms indicate a defective control unit. Replace the control unit. 2- n connection with pads. a) When touching the pads;a certain group of pads do not produce a signal. b) When touching the pads, no pads produce a signal. 2-2 n connection with indicators a) At a certain digit, all or some segments do not light up. b) At a certain digit, brightness is low. c) Only one indicator does not light up. d) The corresponding segments of all digits do not light up; or they continue to light up. e) Wrong figure appears. f) A certain group of indicators do not light up. g) The figure of all digits flicker. 2-3 Other possible troubles caused by defective control unit. a) Buzzer does not sound or continues to sound. b) Clock does not operate properly. c) Cooking is not possible. d) Proper temperature measurement is not obtained. Note: When defective components, the Control Unit, Key Unit or Relay Unit are replaced, the defective part or parts must be properly packed for return in the shipping carton, with its cushion material, in which the new replacement part was shipped to you. (RD82SOl U) P KEY UNT TEST f the indicator does not respond to touching a key Pad use the following matrix and place a jumper wire between the proper pin connections making momentary contact with the cable connector disconnected from the control unit. f the indicator responds and oven goes into operation, the key unit was faulty. f there is no response, replace the control unit, -9 5-l 3 60 C 4 50 C 3 3o c 2 70 C 40% C C C 7 200% 6 80% LowM HGH MED HGH MED MU) Low LOW F CLOCK CLEAR COOK HOU) D KEY UNT ] 9

21 TEST PROCEDURES (CONT O) PROCEDURE LETTER COMPONENT TEST 0 AH SENSOR TEST Checking the initial sensor cooking condition () The oven should be plugged in at least five minutes befor sensor cooking. (2) Room temperature should not exceed 35 C. (3) The unit should not be installed in any area where heart and steam are generated. The unit should not be installed, for example, next to a conventional surface unit. Refer to the NSTALLATON nstruction. (4) Exhaust vents are providend on the back of the unit for proper cooling and air flow in the cavity.to permit adequate ventilation, be sure to install so as not to block these vents, There should besome space for air circulation. (5) 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. (6) The Sensor works with food at normal storage temperature.for example, chicken pieces would be at refrigerator temperature and canned soup at room temperature. (7) Avoid using aerosol sprays or cleaning solvents near the oven while using Sensor settings. The sensor will detect the vapor given of by the spray and turn off befor food is properly cooked. (8) After 30 minutes if the sensor has not detected the vapor of the food, ERROR will appear and the oven will shut off. Water load cooking test Make sure the oven has been plugged in at least five minutes before checking sensor cook operation The cabinet should be installed and screws tightened. () Fill approximately 200 milliliters (7.2 oz) of tap water in a 000 milliliter measuring cup. (2) Place the container on the center of tray in the oven cavity. (3) Close the door. (4) Touch SENSOR COOK pad and number pad. Now, the oven is in the sensor cooking condition and SC-l will appear in the display. (5) Touch Start pad.the oven will operate for the first 6 seconds, without generating microwave energy. When the AH sensor is defective (open or short), ERROR will appear in the display after 6 seconds cooling time. f ERROR appears check sensor wire connections and/or AH sensor. NOTE: ERROR will appear if the door is opend or STOP/CLEAR pad is touched during first stage of sensor cooking. (6) After approximately 6 seconds, microwave energy is produced, oven should turn off when water is boiling (bubling). f the oven does not turn off, replace the AH sensor or check the control nation below: unit, refer to expla- TESTNG METHOD FOR AH SENSOR AND/OR CONTROL UNT To determine if the sensor is defective, the simplest method is to replace it with a new replacement sensor. () Disconnect oven from power supply and remove outer case. (2) Discharge the high voltage capacitor. (3) Remove the AH sensor. (4) nstall the new AH sensor. (5) Re-install the outer case. (6) Reconnect the oven to the power supply andcheck the sensor cook operation proceed as follows: 6-. Touch SENSOR COOK pad and number 0 pad Touch Start pad. The control panel is in automatic Sensor operation The oven will turn off automatically when the water is boiling (bubling). f new sensor dose not operate properly, the problem is with the control unit. 20

22 R-8580 TEST PROCEDURES (CONT D) PROCEDURE LETTER COMPONENT TEST CHECKNG CONTROL UNT () Disconnect oven from power supply and remove outer case. (2) Discharge the high voltage capacitor. (3) Disconnect the wire leads from the cook relay. (4) Disconnect the sensor connector that is mounted to lower position of control panel. (5) Then connect the dummy resistor circuit (see fig.) to the sensor connector of control panel. (6) Reconnect the oven to the power supply and check the sensor cook operation proceed as follows: 6-. Touch SENSOR COOK pad and number 0 pad The control panel is in the sensor cooking operation After approximately 20 seconds, push plunger of select switch. This condition is same as judgement by AH sensor After approximately 3 seconds, cooking operation turns off, an audible signal will sound, and the display will then revert to the time of day. f the above is not the case, the control unit is probably defective. f the above is proper, the AH sensor is probably defective. Plunger 0-J To Connector (F) on Control Untt CONNECTOR NC NO Rl, R2 : loon t % /2w R3 : 0kR? 5% /4W R4 : 2kR * 5% /4W F-l - F F-3 rc- R2 R4 ino. -2 Switch Sensor Dummy Resistor Circuit R PROCEDURES TO BE TAKEN WHEN THE FOL PATTERN ON THE PRNTED WRNG BOARD(PWB) S OPEN. To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary on the PWB, and this fine pattern service as a substitute coil. f the foil pattern is open, follow the troubleshooting guide given below for repair. Problem: _.-- POWER C JN, indicator does not light up. STEPS OCCURANCE CAUSE OR CORRECTON The rated voltage is not applied to POWER terminal Check supply voltage and oven main unit. of CPU connector (CN-A) 2 The rated voltage is applied to primarv side of Dower Power transformer or secondarv circuit defective. NOTE:* At the time of these repairs, make 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). f any abnormal condition is detected, replace the defective parts. 2