Sharp R930cs Service Manual
Have a look at the manual Sharp R930cs Service Manual online for free. It’s possible to download the document as PDF or print. UserManuals.tech offer 615 Sharp manuals and user’s guides for free. Share the user manual or guide on Facebook, Twitter or Google+.
R-930CS In the interest of user-safety the oven should be restored to its original condition and only parts identical to those specified should be used. WARNING TO SERVICE PERSONNEL: Microwave ovens con- tain circuitry capable of producing very high voltage and current, contact with following parts may result in a severe, possibly fatal, electrical shock. (High Voltage Capacitor, High Voltage Power Transformer, Magnetron, High Voltage Recti- fier Assembly, High Voltage Harness etc..) TABLE OF CONTENTS CONVECTION MICROWAVE OVEN Page PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICE TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY ................... INSIDE FRONT COVER BEFORE SERVICING ...................................................................................................... INSIDE FRONT COVER WARNING TO SERVICE PERSONNEL ................................................................................................................ 1 MICROWAVE MEASUREMENT PROCEDURE ................................................................................................... 2 FOREWORD AND WARNING ............................................................................................................................... 3 PRODUCT SPECIFICATIONS .............................................................................................................................. 4 GENERAL INFORMATION ................................................................................................................................... 4 OPERATION .......................................................................................................................................................... 6 TROUBLESHOOTING GUIDE ............................................................................................................................ 12 TEST PROCEDURE ............................................................................................................................................ 14 TOUCH CONTROL PANEL ................................................................................................................................. 25 COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ................................................................ 31 PICTORIAL DIAGRAM ........................................................................................................................................ 38 CONTROL PANEL CIRCUIT ............................................................................................................................... 39 PRINTED WIRING BOARD ................................................................................................................................. 40 PARTS LIST ........................................................................................................................................................ 41 PACKING AND ACCESSORIES ......................................................................................................................... 44 R-930CS S9913R930CPST MODEL SERVICE MANUAL SHARP CORPORATION This document has been published to be used for after sales service only. The contents are subject to change without notice. CONVECTION Custom Help Sensor CookConvecvtionCompu BroilCompu RoastCompu Bake Sensor Reheat Popcorn Elevate PKGMinute Plus Compu Defrost Preheat Convec Broil Slow Cook Kitchen Timer Power LevelClock Low Mix Bake Stop Clear Sart Touch OnHigh Mix Roast 1 Baked potatoes 2 Frozen vegetables 3 Fresh veg-soft 4 Fresh veg-hard 5 Frozen entrees 6 Hot dogs 7 Bacon 8 Fish, seafood 1 Hamburgers 2 Chicken pieces 3 Steaks 4 Fish steaks 1 Chicken 2 Turkey 3 Turkey breast 4 Pork 1 Bundt cake 2 Cookies 3 Muffins 4 French fries Interactive 12 3 4 5 67 8 9 0100˚F 150˚F 275˚F 300˚F 325˚F 350˚F 375˚F 400˚F 425˚F 450˚F
R-930CS PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY (a) Do not operate or allow the oven to be operated with the door open. (b) Make the following safety checks on all ovens to be serviced before activating the magnetron or other microwave source, and make repairs as necessary: (1) interlock operation, (2) proper door closing, (3) seal and sealing surfaces (arcing, wear, and other damage), (4) damage to or loosening of hinges and latches, (5) evidence of dropping or abuse. (c) Before turning on microwave power for any service test or inspection within the microwave generating compartments, check the magnetron, wave guide or transmission line, and cavity for proper alignment, integrity, and connections. (d) Any defective or misadjusted components in the interlock, monitor, door seal, and microwave generation and transmission systems shall be repaired, replaced, or adjusted by procedures described in this manual before the oven is released to the owner. (e) A microwave leakage check to verify compliance with the Federal Performance Standard should be performed on each oven prior to release to the owner. BEFORE SERVICING Before servicing an operative unit, perform a microwave emission check as per the Microwave Measurement Procedure outlined in this service manual. If microwave emissions level is in excess of the specified limit, contact SHARP ELECTRONICS CORPORATION immediately @1-800-237-4277. If the unit operates with the door open, service person should 1) tell the user not to operate the oven and 2) contact SHARP ELECTRONICS CORPORATION and Food and Drug Administrations Center for Devices and Radiological Health immediately. Service personnel should inform SHARP ELECTRONICS CORPORATION of any certified unit found with emissions in excess of 4mW/cm 2. The owner of the unit should be instructed not to use the unit until the oven has been brought into compliance.
1 R-930CS WARNING TO SERVICE PERSONNEL Microwave ovens contain circuitry capable of pro- ducing very high voltage and current, contact with following parts may result in a severe, possibly fatal, electrical shock. (Example) High Voltage Capacitor, High Voltage Power Trans- former, Magnetron, High Voltage Rectifier Assem- bly, High Voltage Harness etc.. Read the Service Manual carefully and follow all instructions. Before Servicing 1. Disconnect the power supply cord , and then remove outer case. 2. Open the door and block it open. 3. Discharge high voltage capacitor. WARNING: RISK OF ELECTRIC SHOCK. DISCHARGE THE HIGH-VOLTAGE CAPACITOR BEFORE SERVICING. 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 the connecting lead of the high- voltage rectifier) against the chassis with the use of an insulated screwdriver. Whenever troubleshooting is performed the power supply must be disconnected. It may, in some cases, be necessary to connect the power supply after the outer case has been removed, in this event, 1. Disconnect the power supply cord, and then remove outer case. 2. Open the door and block it open. 3. Discharge high voltage capacitor. 4. Disconnect the leads to the primary of the power transformer. 5. Ensure that the leads remain isolated from other components and oven chassis by using insulation tape. 6. After that procedure, reconnect the power supply cord. When the testing is completed, 1. Disconnect the power supply cord, and then remove outer case. 2. Open the door and block it open. 3. Discharge high voltage capacitor. 4. Reconnect the leads to the primary of the power transformer. 5. Reinstall the outer case (cabinet). 6. Reconnect the power supply cord after the outer case is installed. 7. Run the oven and check all functions. After repairing 1. Reconnect all leads removed from components during testing. 2. Reinstall the outer case (cabinet). 3. Reconnect the power supply cord after the outer case is installed. 4. Run the oven and check all functions. Microwave ovens should not be run empty. To test for the presence of microwave energy within a cavity, place a cup of cold water on the oven turntable, close the door and set the power to HIGH and set the microwave timer for two (2) minutes. When the two minutes has elapsed (timer at zero) carefully check that the water is now hot. If the water remains cold carry out Before Servicing procedure and re- examine the connections to the component being tested. When all service work is completed and the oven is fully assembled, the microwave power output should be checked and a microwave leakage test should be carried out. Dont Touch ! Danger High Voltage
2 R-930CS MICROWAVE MEASUREMENT PROCEDURE A. Requirements: 1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should not exceed 1mW/cm 2 at any point 5cm or more from the external surface of the oven, measured prior to acquisition by a purchaser, and thereafter (through the useful life of the oven), 5 mW/cm2 at any point 5cm or more from the external surface of the oven. 2) Safety interlock switches Primary interlock relay and door sensing switch shall prevent microwave radiation emission in excess of the requirement as above mentioned, secondary interlock switch shall prevent microwave radiation emission in excess of 5 mW/cm 2 at any point 5cm or more from the external surface of the oven. B. Preparation for testing: Before beginning the actual measurement of leakage, proceed as follows: 1) Make sure that the actual 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, 21 CFR 1030.10(c)(3)(i), must be used for testing. 2) Place the oven tray in the oven cavity. 3) Place the load of 275±15 ml (9.8 oz) of tap water initially at 20±5ûC (68ûF) in the center of the oven cavity. The water container shall be a low form of 600 ml (20 oz) beaker with an inside diameter of approx. 8.5 cm (3-1/2 in.) and made of an electrically nonconductive 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) Set the cooking control on Full Power Cooking Mode. 5) Close the door and select a cook cycle of several minutes. If the water begins to boil before the survey is completed, replace it with 275 ml of cool water. C. Leakage test: Closed-door leakage test (microwave measurement) 1) Grasp the probe of the survey instrument and hold it perpendicular to the gap between the door and the body of the oven. 2) Move the probe slowly, not faster than 1 in./sec. (2.5 cm/sec.) along the gap, watching for the maximum indication on the meter. 3) Check for leakage at the door screen, sheet metal seams and other accessible positions where the continuity of the metal has been breached (eg., around the switches, indicator, and vents). While testing for leakage around the door pull the door away from the front of the oven as far as is permitted by the closed latch assembly. 4) Measure carefully at the point of highest leakage and make sure that the highest leakage is no greater than 4mW/cm 2, and that the secondary interlock switch does turn the oven OFF before any door movement. NOTE: After servicing, record data on service invoice and microwave leakage report.
3 R-930CS PRODUCT DESCRIPTION GENERAL INFORMATION OPERATION TROUBLESHOOTING GUIDE AND TEST PROCEDURE TOUCH CONTROL PANEL COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE WIRING DIAGRAM PARTS LIST SHARP ELECTRONICS CORPORATION SHARP PLAZA, MAHWAH, NEW JERSEY 07430-2135 SERVICE MANUAL CONVECTION MICROWAVE OVEN R-930CS FOREWORD This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with Operation and Service Information for the SHARP CONVECTION MICROWAVE OVEN, R-930CS. It is recommended that service personnel carefully study the entire text of this manual so that they will be qualified to render satisfactory customer service. Check the interlock switches and the door seal carefully. Special attention should be given to avoid electrical shock and microwave radiation hazard. WARNING Never operate the oven until the following points are ensured. (A) The door is tightly closed. (B) The door brackets and hinges are not defective. (C) The door packing is not damaged. (D) The door is not deformed or warped. (E) There is no other visible damage with the oven. Servicing and repair work must be carried out only by trained service personnel. DANGER Certain initial parts are intentionally not grounded and present a risk of electrical shock only during servicing. Service personnel - Do not contact the following parts while the appliance is energized; High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness; If provided, Vent Hood, Fan assembly, Cooling Fan Motor. All the parts marked Ò*Ó on parts list are used at voltages more than 250V. Removal of the outer wrap gives access to voltage above 250V. All the parts marked ÒDÓ on parts list may cause undue microwave exposure, by themselves, or when they are damaged, loosened or removed.
4 R-930CS SPECIFICATION ITEM DESCRIPTION Power Requirements 120 Volts 13.0 Amperes (Microwave) / 13.0 Amperes (Convection) 60 Hertz / Single phase, 3 wire grounded Power Output 900 watts (IEC 705 Test Procedure) Operating frequency of 2450MHz Convection Power Output 1450 Watts Case Dimensions Width 24-5/8 Height 14-7/8 Depth 19 Cooking Cavity Dimensions (1.5 Cubic Feet ) Width 16-1/8 Height 9-5/8 Depth 16-1/8 Control Complement Touch Control System Timer (0 - 99 min. 99 seconds) Microwave Power for Variable Cooking Repetition Rate; P-HI ........................................... Full power throughout the cooking time P-90 ............................................................. approx. 90% of Full Power P-80 ............................................................. approx. 80% of Full Power P-70 ............................................................. approx. 70% of Full Power P-60 ............................................................. approx. 60% of Full Power P-50 ............................................................. approx. 50% of Full Power P-40 .............................................................. approx. 40% of Full Power P-30 .............................................................. approx. 30% of Full Power P-20 ............................................................. approx. 20% of Full Power P-10 .............................................................. approx. 10% of Full Power P-0 ............................................. No power throughout the cooking time Convection Temperature for Variable Cooking CONVECTION .............................................. 100 - 450ûF Temp. control LOW MIX. BAKE ............................... 350ûF with 10% microwave power HIGH MIX. ROAST ........................... 300ûF with 30% microwave power SLOW COOK .......................................... 300ûF for 4 hours (no preheat) BROIL ............................................................................ 450ûF (preheat) CUSTOM HELP pad, SENSOR REHEAT pad, MINUTE PLUS pad, POPCORN pad COMPU DEFROST pad, SENSOR COOK pad, COMPU BROIL pad COMPU ROAST pad, COMPU BAKE pad, REHEAT pad, CONVEC pad BROIL pad, SLOW COOK pad, HIGH MIX / ROAST pad, LOW MIX / BAKE pad Number and temperature selection pads, KITCHEN TIMER pad, CLOCK pad STOP/CLEAR pad, POWER LEVEL pad, START / TOUCH ON pad Oven Cavity Light Yes Safety Standard UL Listed FCC Authorized DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J GENERAL INFORMATION GROUNDING INSTRUCTIONS This oven is equipped with a three prong grounding plug. It must be plugged into a wall receptacle that is properly installed and grounded in accordance with the National Electrical Code and local codes and ordinances. In the event of an electrical short circuit, grounding reduces the risk of electric shock by providing an escape wire for the electric current. WARNING: Improper use of the grounding plug can result in a risk of electric shock.
5 R-930CS Electrical Requirements The electrical requirements are a 115 -120 volt 60 Hz, AC only, 15 or 20 amp. fused electrical supply. It is recommended that a separate circuit serving only this appliance be provided. When installing this appliance, observe all applicable codes and ordinances. A short power-supply cord is provided to reduce risks of becoming entangled in or tripping over a longer cord. Where a two-pronged wall-receptacle is encountered, it is the personal responsibility and obligation of the customer to contact a qualified electrician and have it replaced with a properly grounded three-pronged wall receptacle or have a grounding adapter properly grounded and polarized. If an extension cord must be used, it should be a 3-wire, 15 amp. or more cord. Do not drape over a countertop or table where it can be pulled on by children or tripped over accidentally. 3-Pronged PlugGrounded Receptacle Box Grounding Pin 3-Pronged Receptacle CAUTION: DO NOT UNDER ANY CIRCUMSTANCES CUT OR REMOVE THE ROUND GROUNDING PRONG FROM THIS PLUG. OVEN DIAGRAM 1. Ventilation openings. (Rear side) 2. Oven door with see-through window. 3. Oven lamp. 4. Turntable support. 5. Removable turntable. The turntable will rotate clockwise or counterclockwise. 6. Safety door latches. The oven will not operate unless the door is securely closed. 7. Wave guide cover. 8. Door open button. 9. Auto-Touch control panel. 10. Lighted digital display. 11. Convection air openings. 12. Removable low rack. (Broiling trivet) 13. Removable low rack. (Baking rack) 14. Power supply cord. 15. Turntable motor shaft. TOUCH CONTROL PANEL MIX CONV DEFROST SENSOR COOK LBS OZ KG HELP Sensor Cook Convection Sensor Reheat Popcorn Elevate PKG Minute Plus Compu Defrost Preheat Convec Broil Slow Cook Kitchen Timer Power LevelClock Low Mix Bake Stop Clear Start Touch OnHigh Mix Roast 1 Baked potatoes 2 Frozen vegetables 3 Fresh veg-soft 4 Fresh veg-hard 5 Frozen entrees 6 Hot dogs 7 Bacon 8 Fish, seafood 1 Hamburgers 2 Chicken pieces 3 Steaks 4 Fish steaks 1 Chicken 2 Turkey 3 Turkey breast 4 Pork 1 Bundt cake 2 Cookies 3 Muffins 4 French fries Interactive 12 3 4 5 67 8 9 0100˚F 150˚F 275˚F 300˚F 325˚F 350˚F 375˚F 400˚F 425˚F 450˚F Compu Broil Compu Roast Compu Bake Custom Help 173 10 9 8 2 5 4 12 13 1415116 6
6 R-930CS OPERATION DESCRIPTION OF OPERATING SEQUENCE The following is a description of component functions during oven operation. OFF CONDITION Closing the door activates the door sensing switch and secondary interlock switch. (In this condition, the monitor switch contacts are opened.) When oven is plugged in, 120 volts A.C. is supplied to the control unit. (Figure O-1). 1. The display will show SHARP SIMPLY THE BEST PRESS CLEAR AND PRESS CLOCK. To set any program or set the clock, you must first touch the STOP/CLEAR pad. The display will clear, and : will appear. NOTE: When the door is opened, the oven lamp comes on. 2. A signal is input to the control unit, energizing the coil of shut-off relay (RY-4). RY4 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 RY-4 is de-energized, opening its contacts, thereby turning off the damper motor. COOKING CONDITION Program desired cooking time Variable Cooking Control by touching the NUMBER pads and the power level pad. When the START pad is touched, the following operations occur: 1. 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-1 Oven lamp/Turntable motor RY-2 Power transformer RY-3 Heating element RY-4 Damper motor RY-5 Convection motor RY-6 Fan motor 2. 120 volts A.C. is supplied to the primary winding of the power transformer and is converted to about 3 volts A.C. output on the filament winding, and approximately 2360 volts A.C. on the high voltage winding. 3. The filament winding voltage heats the magnetron filament and the H.V. winding voltage is sent to a voltage doubler circuit. 4. The microwave energy produced by the magnetron is channelled 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, door sensing switch, the primary interlock relayand the secondary interlock switch are activated with the following results. The circuits to the turntable motor, the cooling fan motor, and the high voltage components are de-energized, the oven lamp remains on, and the digital read-out 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 primary interlock relay and the secondary interlock switch and is mechanically associated with the door so that it will function in the following sequence. (1) When the door opens from a closed position, the primary interlock relay and the secondary interlock 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 primary interlock relay and the secondary interlock switch close. If the primary interlock relay and the secondary interlock 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 monitor fuse, primary interlock relay and the secondary interlock switch, causing the moni- tor fuse to blow. POWER LEVEL P-0 TO P-90 COOKING When Variable Cooking Power is programmed, the 120 volts A.C. is supplied to the power transformer intermittently through the contacts of relay (RY-2). RY-2 is operated by the control unit within an varying time base. Microwave power operation is as follows: VARI-MODE ON TIME OFF TIME Power 10(P-HI) (100% power) 32 sec. 0 sec. Power 9(P-90) (approx. 90% power) 30 sec. 2 sec. Power 8(P-80) (approx. 80% power) 26 sec. 6 sec. Power 7(P-70) (approx. 70% power) 24 sec. 8 sec. Power 6(P-60) (approx. 60% power) 22 sec. 10 sec. Power 5(P-50) (approx. 50% power) 18 sec. 14 sec. Power 4(P-40) (approx. 40% power) 16 sec. 16 sec. Power 3(P-30) (approx. 30% power) 12 sec. 20 sec. Power 2(P-20) (approx. 20% power) 8 sec. 24 sec. Power 1(P-10)(approx. 10% power) 6 sec. 26 sec. Power 0(P-0) (0% power) 0 sec. 32 sec. 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. CONVECTION COOKING CONDITION PREHEATING CONDITION Program desired convection temperature by touching the CONVECTION pad and the Temperature pad. When the START pad is touched, the following operations occur: 1. The coil of shut-off relays (RY1, RY3,RY5 and RY6) are energized, the oven lamp, cooling fan motor, turntable
7 R-930CS motor and convection motor are turned on. 2. The coil of relay (RY4) is energized by the control 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 LSI on the control unit de-energizing the relay (RY4) and opening the circuit to the damper motor. 3. The coil of heater relay (RY3) is energized by the control unit and the main supply voltage is applied to the heating element. 4. When the oven temperature reaches the selected preheat temperature, the following operations occur: 4-1 The heater relay is de-energized by the control unit temperature circuit and thermistor, opening the circuit to the heating element. 4-2. The oven will continue to function for 30 minutes, turning the heater on and off, as needed to maintain the selected preheat temperature. The oven will shut-down completely after 30 minutes CONVECTION COOKING CONDITION 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. Touch the CONVEC pad first and then touch the Temperature pad. And program desired cooking time by touching the Number pads. When the START pad is touched, the following operations occur: 1. The numbers on the digital read-out start to count down to zero. 2. The oven lamp, turntable motor, cooling fan motor and convection motor are energized. 3. Heater relay (RY3) is energized (if the cavity temperature is lower than the selected temperature) and the main supply voltage is applied to the heating element to return to the selected cooking temperature. 4. 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 275ûF, the circuit to RY6 will be maintained (by the thermistor circuit) to continue operation of the cooling fan motor until the temperature drops below 245ûF, at which time the relay will be de-energized, turning off the fan motor. Relay RY5 will however, open as soon as the convection cycle has ended, turning off the convection fan motor. 5. At the end of the convection cook cycle, shut-off relay (RY4) 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 (RY4). AUTOMATIC MIX COOKING CONDITION Touch the HIGH MIX/ROAST or the LOW MIX/BAKE pad first. And then program desired cooking time by touching the Number pads. The LOW MIX/BAKE pad is preprogrammed for 350ûF with 10% microwave power, while the HIGH MIX/ ROAST pad is preprogrammed for 300ûF with 30% micro- wave power. When the START pad is touched, the following operations occur: 1. The numbers on the digital read-out start to count downto zero. 2. The shut-off relays (RY1,RY2,RY3,RY5 and RY6) are energized, turning on the oven lamp, turntable motor, cooling fan motor and convection fan motor. 3. The shut-off relay (RY4) is energized. The damper door is closed from the open position. 4. The heater relay (RY3) is energized, applying the main supply voltage to the heating element. 5. Now, the oven is in the convection cooking condition. 6. When the oven temperature reaches the selected temperature, the following operations occur: 6-1. The power supply voltage is alternated to the heating element and power transformer. 6-2. The heating element operates through the heater relay (RY3) contacts and the power transformer operates through the primary interlock relay (RY2) contacts. 6-3. These are operated by the control unit to supply alternately within a 32 second time base, convection heat and microwave energy. The relationship between the convection and microwave power operations are as follows. 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. Note: During alternate Microwave/Convection operation, the convection heater is energized only if the cavity temperature drops below the set temperature. SENSOR COOKING CONDITION 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 informa- tion 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 ÒsensesÓ 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 experi- ment with each food category and inputted into the LSI. 12 SEC. 20 SEC. 32 SEC. LOW MIX BAKE HIGH MIX ROAST MICROWAVE POWER = APPROX. 30% CONVECTION TEMPERATUE = 300˚F MICROWAVE POWER = APPROX. 10% CONVECTION TEMPERATUE = 350˚F (180˚C) 26 SEC. 6 SEC. ON ON OFFOFF OFF ON (MICRO.) (CONVEC.)(MICRO.) (CONVEC.)
8 R-930CS CONVECTION MOTOR THERMISTOR Sensing VoltageON OFF ON OFF ON OFF 0 2 24 30 64 (sec.) 3 sec. Sensing the voltage across the temperature measurement circuit. 6 sec. 332 (sec.) An example of how sensor works: 1. Potatoes at room temperature. Vapor is emitted very slowly. 2. Heat potatoes. 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. 1. Touch SENSOR COOK pad. NOTE: The oven should not be operated on SENSOR COOK immediately after plugging in the unit. Wait two minutes before cooking on SENSOR COOK. 2. Select desired Sensor setting. 3. Touch START pad. The coil of shut-off relay (RY1, RY6) is energized, the oven lamp and cooling fan motor are turned on, but the power transformer is not turned on. 4. After about 16 seconds, the cook relay (RY-2) is energized. The power transformer is turned on, microwave energy is produced and first stage is started. The 16 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 BROIL/ COMPU ROAST/ COMPU BAKE COMPU BROIL/ ROAST/ BAKE will automatically compute the oven temperature, microwave power and cooking time for baking, roasting and broiling. Set the desired program by touching the COMPU BROIL/ ROAST/ BAKE pad, and number pad. Enter the weight by touching the Number pads. When the START pad is touched, the following operations occur: 1. 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 (RY1, RY5 and RY6) are energized, turning on the oven lamp, turntable motor, cooling fan motor and convection motor. The power supply voltage is applied to the heating element. 4. Now, the oven is in the convection cooking mode. 5. When the oven temperature has reached the programmedconvection temperature, the oven goes into the programmed cooking mode. 6. At the end of the COMPU BROIL/ ROAST/ BAKE 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. COMPU DEFROST COOKING The COMPU DEFROST key is a special function key to defrost meats and poultry faster and better. COMPU DE- FROST automatically defrosts roast beef, etc.. When the COMPU DEFROST is selected and the food weight is entered by using the COMPU DEFROST pad, the oven will cook according to the special cooking sequence. FIRE SENSING FEATURE (MICROWAVE MODE) This model incorporates a sensing feature which will stop the ovens operation if there is a fire in the oven cavity during microwave cooking. This is accomplished by the LSI repeat- edly measuring the voltage across the temperature meas- urement circuit (thermistor) during its 32-seconds time base comparing the obtained voltage measurements. If the most recent voltage measured is 300mV greater than the previous voltage measured, the LSI judges it as a fire in the oven cavity and switches off the relays to the power trans- former, fan motor and convection motor. The LSI also stops counting down and closes the damper door so that no fresh air will enter the oven cavity. Please refer to the following section for a more detailed description. Operation Please refer to the timing diagrams below. 1. The thermistor operates within a 32-seconds time base and it is energized for three (3) seconds and off for 29 seconds. Two (2) seconds after the thermistor is energized, the voltage across the temperature measurement circuit is sampled by the LSI and twenty one (21) seconds after the thermistor is cut off the LSI turns on the cooling fan for six (6) seconds. 2. The above procedure is repeated. If the difference between the first voltage measured (in step 1) and the voltage measured when the procedure is repeated (step 2) is greater than 300mV the LSI makes the judgment that there is a fire in the oven cavity and will switch off the relays to the power transformer, fan motor and convection motor. The LSI also stops counting down and closes the damper door so that no fresh air will enter the oven cavity. 3. Once the fire sensor feature has shut the unit down, the programmed cooking cycle may be resumed by pressing the START pad or the unit may be reset by pressing the CLEAR pad. MICROWAVE MICROWAVEAH SENSOR