Sharp R820jsf Service Manual
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R-820JS 9 SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. 2.MICROWAVE POWER LEVEL PAD PRESSED ONCE(100%). 3. COOKING TIME PROGRAMMED. 4. START PAD TOUCHED. Figure O-2 Oven Schematic-Microwave cooking Condition SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. 2. : OR CLOCK APPEAR ON DISPLAY.NOTE: Indicates components with potential above 250 V. Figure O-1 Oven Schematic-OFF Condition FMTTMOVEN LAMPFAN MOTOR TURNTABLE MOTOR H.V. RECTIFIER CONTROL UNIT RPIMARY INTERLOCK RELAY COM. COM.COM.N.O. COM. N.O. N.O.N.O. A1 DOOR SENSING SWITCH BRN BLU G-Y EARTH LIVE NEUTRAL RY4 RY3 RY2: RY6RY5 CMCONVECTION MOTORTHERMISTOR RY1 CAPACITOR 0.94µF AC2200VGRILL HEATER (TOP) BOTTOM HEATER MAGNETRONPOWER TRANSFORMER B2B1 A3 A5 D1 D3 SECONDARY INTERLOCK SWITCH THERMAL CUT-OUT (OVEN) THERMAL CUT-OUT (MAG.) MONITOR SWITCHFUSE 20A 120V ~ 60Hz OL FMTTMOVEN LAMPFAN MOTOR TURNTABLE MOTOR H.V. RECTIFIER CONTROL UNIT RPIMARY INTERLOCK RELAY COM. COM.COM.N.O. COM. N.O. N.O.N.O. A1 DOOR SENSING SWITCH BRN BLU G-Y EARTH LIVE NEUTRAL RY4 RY3 RY2: RY6RY5 CMCONVECTION MOTORTHERMISTOR RY1 CAPACITOR 0.94µF AC2200VGRILL HEATER (TOP) BOTTOM HEATER MAGNETRONPOWER TRANSFORMER B2B1 A3 A5 D1 D3 SECONDARY INTERLOCK SWITCH THERMAL CUT-OUT (OVEN) THERMAL CUT-OUT (MAG.) MONITOR SWITCHFUSE 20A 120V ~ 60Hz OL
R-820JS 10 SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. 2. GRILL PAD TOUCHED. 3. NUMBER 2 PAD TOUCHED. 4. COOKING TIME PROGRAMMED. 5. START PAD TOUCHED.SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. 2. GRILL PAD TOUCHED. 3. NUMBER 1 PAD TOUCHED. 4. COOKING TIME PROGRAMMED. 5. START PAD TOUCHED. Figure O-3a Oven Schematic-Grill cooking Condition (TOP AND BOTTOM HEATER mode) NOTE: Indicates components with potential above 250 V. Figure O-3b Oven Schematic-Grill cooking Condition (TOP HEATER mode) FMTTMOVEN LAMPFAN MOTOR TURNTABLE MOTOR H.V. RECTIFIER CONTROL UNIT RPIMARY INTERLOCK RELAY COM. COM.COM.N.O. COM. N.O. N.O.N.O. A1 DOOR SENSING SWITCH BRN BLU G-Y EARTH LIVE NEUTRAL RY4 RY3 RY2: RY6RY5 CMCONVECTION MOTORTHERMISTOR RY1 CAPACITOR 0.94µF AC2200VGRILL HEATER (TOP) BOTTOM HEATER MAGNETRONPOWER TRANSFORMER B2B1 A3 A5 D1 D3 SECONDARY INTERLOCK SWITCH THERMAL CUT-OUT (OVEN) THERMAL CUT-OUT (MAG.) MONITOR SWITCHFUSE 20A 120V ~ 60Hz OL FMTTMOVEN LAMPFAN MOTOR TURNTABLE MOTOR H.V. RECTIFIER CONTROL UNIT RPIMARY INTERLOCK RELAY COM. COM.COM.N.O. COM. N.O. N.O.N.O. A1 DOOR SENSING SWITCH BRN BLU G-Y EARTH LIVE NEUTRAL RY4 RY3 RY2: RY6RY5 CMCONVECTION MOTORTHERMISTOR RY1 CAPACITOR 0.94µF AC2200VGRILL HEATER (TOP) BOTTOM HEATER MAGNETRONPOWER TRANSFORMER B2B1 A3 A5 D1 D3 SECONDARY INTERLOCK SWITCH THERMAL CUT-OUT (OVEN) THERMAL CUT-OUT (MAG.) MONITOR SWITCHFUSE 20A 120V ~ 60Hz OL
R-820JS 11 Figure O-5 Oven Schematic-Roast cooking Condition Figure O-4 Oven Schematic-Convection cooking Condition (Convection with preheat mode) SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. 2. CONVECTION PAD TOUCHED. 3. NUMBER 1 PAD TOUCHED. 4. TEMPERATURE PAD TOUCHED. 5. COOKING TIME PROGRAMMED. 6. START PAD TOUCHED. SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. 2. ROAST PAD TOUCHED. 3. COOKING TIME PROGRAMMED. 4. START PAD TOUCHED. FMTTMOVEN LAMPFAN MOTOR TURNTABLE MOTOR H.V. RECTIFIER CONTROL UNIT RPIMARY INTERLOCK RELAY COM. COM.COM.N.O. COM. N.O. N.O.N.O. A1 DOOR SENSING SWITCH BRN BLU G-Y EARTH LIVE NEUTRAL RY4 RY3 RY2: RY6RY5 CMCONVECTION MOTORTHERMISTOR RY1 CAPACITOR 0.94µF AC2200VGRILL HEATER (TOP) BOTTOM HEATER MAGNETRONPOWER TRANSFORMER B2B1 A3 A5 D1 D3 SECONDARY INTERLOCK SWITCH THERMAL CUT-OUT (OVEN) THERMAL CUT-OUT (MAG.) MONITOR SWITCHFUSE 20A 120V ~ 60Hz OL FMTTMOVEN LAMPFAN MOTOR TURNTABLE MOTOR H.V. RECTIFIER CONTROL UNIT RPIMARY INTERLOCK RELAY COM. COM.COM.N.O. COM. N.O. N.O.N.O. A1 DOOR SENSING SWITCH BRN BLU G-Y EARTH LIVE NEUTRAL RY4 RY3 RY2: RY6RY5 CMCONVECTION MOTORTHERMISTOR RY1 CAPACITOR 0.94µF AC2200VGRILL HEATER (TOP) BOTTOM HEATER MAGNETRONPOWER TRANSFORMER B2B1 A3 A5 D1 D3 SECONDARY INTERLOCK SWITCH THERMAL CUT-OUT (OVEN) THERMAL CUT-OUT (MAG.) MONITOR SWITCHFUSE 20A 120V ~ 60Hz OL NOTE: The microwave relay (RY2) and the heater relay (RY3 or RY4) are not energized simultaneously.
R-820JS 12 DESCRIPTION AND FUNCTION OF COMPONENTS DOOR OPEN MECHANISM The door is opened by pushing the open button on the control panel, refer to Figure D-1. When the open button is pushed, the open button pushes up the switch lever, and then the switch lever pushes up the latch head. The latch heads are moved upward and re- leased from latch hook. Now the door will open.of the monitor switch contacts. CAUTION:BEFORE REPLACING A BLOWN MONITOR FUSE TEST THE DOOR SENSING SWITCH, PRIMARY INTERLOCK RELAY (RY2), RELAY (RY6), SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH FOR PROPER OP- ERATION. (REFER TO CHAPTER TEST PRO- CEDURE). NOTE: MONITOR FUSE AND MONITOR SWITCH ARE REPLACED AS AN ASSEMBLY. TURNTABLE MOTOR The turntable motor rotates the turntable located on the bottom of the oven cavity, so that the food on the turntable cook evenly during cooking. The turntable may turn in either direction. COOLING FAN MOTOR The cooling fan motor drives a blade which draws external cool air. This cool air is directed through the air vanes surrounding the magnetron and cools the magnetron. This air is channelled through the oven cavity to remove steam and vapors given off from the heating food. It is then exhausted through the exhausting air vents at the oven cavity. MONITOR FUSE 1.The monitor fuse blows when the contacts (COM-NO) of the primary interlock relay (RY2) and secondary interlock switch remain closed with the oven door open and when the monitor switch closes. 2. If the wire harness or electrical components are short- circuited, this monitor fuse blows to prevent an electric shock or fire hazard. THERMAL CUT-OUT 125˚C (MAGNETRON) This thermal cut-out protects the magnetron against over- heating. If the temperature goes up higher than 257˚F (125˚C) because the fan motor is interrupted or the ventila- tion openings are blocked, the thermal cut-out will open and line voltages to the high voltage transformer will be cut off and the operation of the magnetron will be stopped. The thermal cut-out will not resume. THERMAL CUT-OUT 170˚C (OVEN) The thermal cut-out located on the top of the oven cavity is designed to prevent damage to the oven if the food in the oven catch fire due to over heating produced by improper setting of the cooking time or failure of control unit. Under the normal operation, the oven thermal cut-out remains closed. However, when abnormally high temperatures are reached within the oven cavity, the oven thermal cut-out will open at 338˚F(170˚C) causing the oven to shut down. The thermal cut-out will close in at 311˚F(155˚C). TOP HEATERS The top heaters are located on the top of the oven cavity assembly. The top heaters send out heat to grill foods. Figure D-1. Door Open Mechanism DOOR SENSING AND SECONDARY INTERLOCK SWITCHES The secondary interlock switch is mounted in the lower position of the latch hook and the door sensing switch in the primary interlock system is mounted in the upper position of the latch hook. They are activated by the latch heads on the door. When the door is opened, the switches interrupt the power to all high voltage components. A cook cycle cannot take place until the door is firmly closed thereby activating both interlock switches. The primary interlock system con- sists of the door sensing switch and primary interlock relay located on the control circuit board. MONITOR SWITCH The monitor switch is activated (the contacts opened) by the latch head on the door while the door is closed. The switch is intended to render the oven inoperative, by means of blowing the monitor fuse, when the contacts of the primary interlock relay (RY2) and secondary interlock switch fail to open when the door is opened. Functions: 1. When the door is opened, the monitor switch contacts close (to the ON condition) due to their being normally closed. At this time the primary interlock relay (RY2) and secondary interlock switch are in the OFF condition (contacts open) due to their being normally open contact switches. 2.As the door goes to a closed position, the monitor switch contacts are first opened and then the door sensing switch and the secondary interlock switch contacts close. (On opening the door, each of these switches operate inversely.) 3.If the door is opened, and the primary interlock relay (RY2) and secondary interlock switch contacts fail to open, the monitor fuse blows simultaneously with closing Latch Hook Door Sensing Switch Monitor Switch Secondary Interlock Switch Switch Lever Latch Heads Door
R-820JS 13 TROUBLESHOOTING GUIDE Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected. When troubleshooting the microwave oven, it is helpful 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. IMPORTANT:If the oven becomes inoperative because of a blown monitor fuse, check the monitor switch, relay (RY6), primary interlock relay (RY2), door sensing switch and secondary interlock switch before replacing the monitor fuse. If monitor fuse is replaced, the monitor switch must also be replaced. Use part FFS- BA021WRK0 as an assembly. IMPORTANT:Whenever troubleshooting is performed with the power supply cord disconnected. It may in, some cases, be necessary to connect the power supply cord 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. BOTTOM HEATER The bottom heater is located on the floor of the oven cavity assembly. The bottom heater sends out heat to grill foods. CONVECTION COOKING SYSTEM This oven is designed with a hot air heating system where food is not directly heated by the top heaters and the bottom heater, but is heated by forced circulation of the hot air produced by the top heaters and the bottom heater. The air heated by the top heaters and the bottom 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. It 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 center of the oven cavity rear wall.Most of this hot air is reheated by the top heaters and the bottom heater and passes through the convection passage and enters the inside of the oven cavity again, in a continu- ing cycle. In 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 top heaters and the bottom heater are de-energized. When the temperature inside the oven cavity drops below the selected temperature, the top heat- ers and the bottom heater are energized again. In this way, the inside of the oven cavity is maintained at approximately the selected temperature. When the convection time reaches 0, the top heaters and the bottom heater are de-energized and the convection fan stops operating and the oven shuts off.
R-820JS 14 CK = Check / RE = Replace ABCDE E F FGH I I J LMNNNNNNOPRE RE RE RE RECK CK CKTEST PROCEDURE MAGNETRON POWER TRANSFORMER H.V. RECTIFIER ASSEMBLY HIGH VOLTAGE CAPACITOR THERMAL CUT-OUT 170˚C THERMAL CUT-OUT 125˚CSECONDARY INTERLOCK SWITCHPRIMARY INTERLOCK SYSTEM MONITOR SWITCH MONITOR FUSE TOP HEATERS BOTTOM HEATER THERMISTOR TOUCH CONTROL PANEL KEY UNIT RELAY RY1 RELAY RY2 RELAY RY3 RELAY RY4 RELAY RY5 RELAY RY6 AUTO DEFROST FOIL PATTURN ON P.W.B. FAN MOTOR CONVECTION MOTOR TURNTABLE MOTOR POWER SUPPLY CORD OVEN LAMP OR SOCKET SHORTED WIRE HARNESS OPENED WIRE HARNESSMIS-ADJUSTMENT OF SWITCHESCONDITIONPROBLEMPOSSIBLE CASE AND DEFECTIVE PARTS Monitor fuse blows when power cord is plugged into wall outlet. Monitor fuse blows when the door is opened. Oven lamp does not light when door is opened. (Display operates.) Home fuse blows when power cord is plugged into wall outlet. SHARP SIMPLY ..... PRESS CLOCK does not appear in display when power cord is plugged into wall outlet. Display does not operate properly when STOP/CLEAR pad is pressed. Oven does not start when the START pad is pressed. (Display operates.) Oven lamp does not light. (Turntable motor operates.) Fan motor does not operate. (Oven lamp lights.) Turntable motor does not operate. (Oven lamp lights.) Oven or electrical parts does not stop when cooking time is 0 or STOP/CLEAR pad is pressed. Oven goes into cook cycle but shuts down before end of cooking cycle. Oven seems to be operating but little or no heat is produced in oven load. Oven does not operate properly during variable cooking condition except 100% cooking condition. Function of AUTO DEFROST does not operate properly. Top heaters do not operate. Bottom heater does not operate. Oven seems to be operating but little or no heat is produced in oven load. (Microwave power does not seem to be generated properly.) Top heaters do not operate. Bottom heater does not operate. Temperature is lower or higher than preset. Convection motor does not operate. Oven stops after 4 minutes 15 sec.. OFF CONDITION COOKING CONDITION (COMMON MODE) MICROWAVE COOKING CONDITION GRILL COOKING CONDITION ROAST COOKING CONDITION CONVECTION COOKING CONDITION
R-820JS 15 BPOWER TRANSFORMER TEST 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 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 1 scale, the resistance of the primary coil should be less than 1 ohm and the resistance of the high voltage coil should be approximately 73 ohms; the resistance of the filament coil should be less than 1 ohm. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. AMAGNETRON ASSEMBLY TEST TEST PROCEDURES PROCEDURE LETTERCOMPONENT TEST 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. 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 1 ohm. 5.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. If there is little or no resistance the magnetron is grounded and must be replaced. 6. Reconnect all leads removed from components during testing. 7. Reinstall the outer case (cabinet). 8. Reconnect the power supply cord after the outer case is installed. 9. Run the oven and check all functions. MICROWAVE OUTPUT POWER The following test procedure should be carried out with the microwave oven in a fully assembled condition (outer case fitted). HIGH VOLTAGES ARE PRESENT DURING THE COOK CYCLE, SO EXTREME CAUTION SHOULD BE OBSERVED. Power output of the magnetron can be measured by performing a water temperature rise test. This test should only be used if above tests do not indicate a faulty magnetron and there is no defect in the following components or wiring: silicon rectifier, high voltage capacitor and power transformer. This test will require a 16 ounce (453cc) measuring cup and an accurate mercury thermometer or thermocouple type temperature tester. For accurate results, the following procedure must be followed carefully: 1.Fill the measuring cup with 16 oz. (453cc) of tap water and measure the temperature of the water with a thermometer or thermocouple temperature tester. Stir the thermometer or thermocouple through the water until the temperature stabilizes. Record the temperature of the water. 2.Place the cup of water in the oven. Operate oven at POWER 10(HIGH) selecting more than 60 seconds cook time. Allow the water to heat for 60 seconds, measuring with a stop watch, second hand of a watch or the digital read-out countdown. 3.Remove the cup from the oven and again measure the temperature, making sure to stir the thermometer or thermocouple through the water until the maximum temperature is recorded. 4.Subtract the cold water temperature from the hot water temperature. The normal result should be 22 to 43˚F(12.2 to 23.9˚C) rise in temperature. If the water temperatures are accurately measured and tested for the required time period the test results will indicate if the magnetron tube has low power output (low rise in water temperature) which would extend cooking time or high power output (high rise in water temperature) which would reduce cooking time. Because cooking time can be adjusted to compensate for power output, the magnetron tube assembly should be replaced only if the water temperature rise test indicates a power output well beyond the normal limits. The test is only accurate if the power supply line voltage is 120 volts and the oven cavity is clean.
R-820JS 16 TEST PROCEDURES PROCEDURE LETTERCOMPONENT TEST 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. If the capacitor is open, no high voltage will be available to the magnetron. Disconnect input leads and check for a 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 an open circuit once the capacitor is charged. If the above is not the case, check the capacitor with an ohmmeter to see if it is shorted between either of the terminals and case. If it is shorted, replace the capacitor. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. DHIGH VOLTAGE CAPACITOR TEST ETHERMAL CUT-OUT TEST 170˚C (OVEN) 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. A continuity check across the thermal cut-out terminals should indicate a closed circuit unless the temperature of the thermal cut-out reaches approximately 338˚F(170˚C). The thermal cut-out resets automatically below approximately 311˚F(155˚C). An open thermal cut-out indicates overheating of the oven, check inside of oven cavity for improper setting of cooking time or operation of control unit. Check for restricted air flow through the vent holes of the oven cavity, especially the cooling fan and air guide. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. THERMAL CUT-OUT TEST 125˚C (MAGNETRON) 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.A continuity check across the thermal cut-out terminals should indicate a closed circuit. If the temperature of the magnetron reaches approximately 257˚F(125˚C), the thermal cut-out opens. An open thermal cut-out indicates overheating of the magnetron, exchange the thermal cut-out. Check for restricted air flow to the magnetron, especially the cooling fan air guide. CHIGH VOLTAGE RECTIFIER TEST 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. Isolate the 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 rectifier terminals and observe meter reading. If a short is indicated in both directions, or if an infinite resistance is read in both directions, the rectifier is probably defective and should be replaced. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. NOTE: Be sure to use an ohmmeter that will supply a forward bias voltage of more than 6.3 volts. (HIGH VOLTAGES ARE PRESENT AT THE HIGH VOLTAGE TERMINAL, SO DO NOT ATTEMPT TO MEASURE THE FILAMENT AND HIGH VOLTAGE.)
R-820JS 17 TEST PROCEDURES PROCEDURE LETTERCOMPONENT TEST 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.Before performing this test, make sure that the secondary interlock switch and the primary interlock relay are operating properly, according to the above Switch Test Procedure. Disconnect the wire lead from the monitor switch (COM) 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 actuator is pushed by a screw driver through the lower latch hole on the front plate of the oven cavity 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. CAUTION: IF THE THERMAL CUT-OUT INDICATES AN OPEN CIRCUIT AT ROOM TEMPERATURE, REPLACE THERMAL CUT-OUT. 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.Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) terminal of the switch. The meter should indicate an open circuit with the door open and a closed circuit with the door closed. If improper operation is indicated, replace the secondary interlock switch. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. PRIMARY INTERLOCK SYSTEM TEST DOOR SENSING SWITCH 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.Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) terminal of the switch. The meter should indicate an open circuit with the door open and a closed circuit with the door closed. If improper operation is indicated, replace the door sensing switch. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. NOTE: If the door sensing switch contacts fail in the open position and the door is closed, the cooling fan, turntable and oven light will be activated by relay(RY6). PRIMARY INTERLOCK RELAY (RY2) 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 two (2) wire leads from the male tab terminals of the Primary Interlock Relay. Check the state of the relay contacts using a ohmmeter. The relay contacts should be open. If the relay contacts are closed, replace the circuit board entirely or the relay itself. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. FSECONDARY INTERLOCK SWITCH TEST GMONITOR SWITCH TEST
R-820JS 18 HBLOWN MONITOR FUSE TEST TEST PROCEDURES PROCEDURE LETTERCOMPONENT TEST 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. If the monitor fuse is blown when the door is opened, check the primary interlock relay, secondary interlock switch and monitor switch according to the TEST PROCEDURE for those switches before replacing the blown monitor fuse. CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE, TEST THE PRIMARY INTERLOCK RELAY, SECONDARY INTERLOCK SWITCH, DOOR SENSING SWITCH AND MONITOR SWITCH FOR PROPER OPERATION. If the monitor fuse is blown by improper switch operation, the monitor fuse and monitor switch must be replaced with monitor fuse and monitor switch assembly part number FFS-BA021WRK0, even if the monitor switch operates normally. The monitor fuse and monitor switch assembly is comprised of a 20 ampere fuse and switch. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions.with the door opened (in this condition the plunger of the monitor switch is pushed in), the meter should indicate an open circuit. If improper operation is indicated, the switch may be defective. After testing the monitor switch, reconnect the wire lead to the monitor switch (COM) terminal and check the continuity of the monitor circuit. 5.Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7.Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. SCREW DRIVERRED WHT MONITOR SWITCH OHMMETER ITOP HEATERS AND BOTTOM HEATER TEST 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. Make sure the heater is cooled completely. 5. Resistance of heater. Disconnect the wire leads to the heater to be tested. Using ohmmeter with low resistance range. Check the resistance across the terminals of the heater as described in the following table. Table: Resistance of heater Parts name Resistance Top heaters Approximately 7.2 Ω x 2 = 14.4 Ω Bottom heater Approximately 28.8 Ω 6. Insulation resistance. Disconnect the wire leads to the heater to be tested. Check the insulation resistance between the heater terminal and cavity using a 500V - 100MΩ insulation tester. The insulation resistance should be more than 10 MΩ in the cold start. 7.If the results of above test 5 and/or 6 are out of above specifications, the heater is probably faulty and should be replaced. 8. Reconnect all leads removed from components during testing. 9. Reinstall the outer case (cabinet).