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ORDER NO.PAPMOSH1201015CE
Microwave Oven
NN-SD452W
NN-ST462M
NN-ST452W
BPQ (U.K.)
EPG (Continental Europe)
© Panasonic Appliances Microwave Oven
(Shanghai) Co., Ltd. 2012.
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NN-SD452W / NN-ST462M / NN-ST452W 2
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NN-SD452W / NN-ST462M / NN-ST452W 3
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NN-SD452W / NN-ST462M / NN-ST452W CONTENTS Page Page 1 SCHEMATICDIAGRAM 5 5.1. Primary,SecondaryLatchSwitchinterlocks&Power 2 DESCRIPTIONOFOPERATINGSEQUENCE 6 Relay RY1 15 2.1. Variablepowercookingcontrol 6 5.2. ShortSwitch 15 2.2. Inverterpowersupplycircuit 6 5.3. Magnetron 15 2.3. Turbodefrost,Autocook 6 5.4. keyboardmembrane(Membraneswitchassembly) 15 2.4. Sensorcooking 6 5.5. Inverterpowersupply(U) 16 2.5. Steamsensoranddigitalprogrammercircuit 7 5.6. Temperaturethermistor 16 3 CAUT
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NN-SD452W / NN-ST462M / NN-ST452W 1 SCHEMATICDIAGRAM 5
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NN-SD452W / NN-ST462M / NN-ST452W 2 DESCRIPTIONOFOPERATINGSEQUENCE 2.1. Variablepowercooking 2.4. Sensorcooking control Auto sensor cooking without setting a power level or selecting a time. All that is necessary is to select an Auto Sensor High Voltage Inverter Power Supply (U) controls output power Program before starting to cook. by the signal from Digital Programmer Circuit (DPC). Power relay always stay on, but PWM (Pulse Width Modulation) signal Understanding Auto Sensor Cooking controls m
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NN-SD452W / NN-ST462M / NN-ST452W Explanation of the Auto Sensor Cooking process 1. During the first 10 second period there is no microwave activity. When calculating the T2 time by using the formula below make sure this 10 seconds is subtracted from the T1 time. In other words, T1 time starts at the end of the 10 second period. 2. T1 time The total amount of time it takes the microwave oven to switch to T2 time after the 10second period. 3. T2 time When the steam escapes from the cooking con
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NN-SD452W / NN-ST462M / NN-ST452W 3 CAUTIONSTOBEOBSERVEDWHEN TROUBLESHOOTING Unlike many other appliances, the microwave oven is a high voltage, high current device. It is free from danger in ordinary use, though extreme care should be taken during repair. CAUTION Servicemen should remove their watches & rings whenever working close to or replacing the magnetron. 3.1. Checkthegrounding Do not operate on a two wire extension cord. The microwave oven is designed to be grounded when used. It is imp
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NN-SD452W / NN-ST462M / NN-ST452W Discharging the high voltage capacitors 3.6. Verificationafterrepair WARNING 1. After repair or replacement of parts, make sure that the There is high voltage present with high current capabilities screws of the oven, etc. are neither loosen or missing. in the circuits of the primary and secondary windings, choke Microwave energy might leak if screws are not properly coil and heat sink of the inverter. It is extremely dangerous tightened. to work on or near the
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NN-SD452W / NN-ST462M / NN-ST452W 4 DISASSEMBLYANDPARTSREPLACEMENT PROCEDURE 4.1. Magnetron 1. Discharge the high voltage capacitor. 2. Remove 1 screw holding air guide A on the magnetron. 3. Remove 1 screw holding air guide A on cavity top plate. 4. Remove 1 screws holding thermistor on the magnetron. NOTE: After replacement of the magnetron, tighten mounting screws properly, making sure there is no gap between the waveguide and the magnetron to prevent microwave leakage. CAUTION When repla
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NN-SD452W / NN-ST462M / NN-ST452W 4.5. Doorassembly 1. Support the door, remove 3 screws holding hinge A. 4.3. Lowvoltagetransformer and/or power relays (RY1, RY2) CAUTION: 2. Open the door, remove door(U) and hinge A from cavity. Be sure to ground any static electric charge built up in NOTE: your body before handling the DPC. Support the door before opening. 1. Replace D.P.C. board. (A) Using solder wick or a desoldering tool and 30W soldering iron carefully remove all solder from the termin
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NN-SD452W / NN-ST462M / NN-ST452W 6. Replace other components. 9. Tighten 2 mounting screws. To re-install components: NOTE: After replacement of the defective component parts of the door, reassemble it properly and adjustment so as to prevent an excessive microwave leakage. Adjustment of the door assembly (Refer page 17). 7. Place the hole of hinge A into the door’s upper hinge pin. Be sure the gap between door E and cavity front plate will be 0.3~0.7mm. NOTE: Always perform the microwave lea
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NN-SD452W / NN-ST462M / NN-ST452W 4.6. Turntablemotor 4.7. Steamsensor 1. Remove the motor cover by breaking off at the 8 spots 1. Disconnect connector CN2 from digital programmer circuit indicated by arrows with a cutter or the like. board. 2. Disengage catch hooks on sensor cover C from orifice. NOTE: After removing the motor cover, be sure that cut portions are properly trimmed or bent to the inside so that no sharp edges will be exposed to outside. 3. Remove steam sensor from orifice. 2.
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NN-SD452W / NN-ST462M / NN-ST452W 6. Remove 1 screw holding H.V.Inverter to Inverter bracket. 4.8. Inverterpowersupply CAUTIONS 1. Always leave the grounding plate in place. 2. Always securely tighten the ground screw through the bottom of the chassis (base). 3. Securely connect 3 lead wire connectors. 4. Make sure the heat sink has enough space (gap) from the oven. Take special care not to dress any lead wire over the aluminum heat sink because it is hot. 1. Discharge high voltage charge. 2.
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NN-SD452W / NN-ST462M / NN-ST452W 5 COMPONENTTESTPROCEDURE WARNING 5.3. Magnetron 1. High voltage is present at the output terminals of the High Voltage Inverter (U) including aluminum heat sink during any cook cycle. Continuity checks can only indicate an open filament or a 2. It is neither necessary nor advisable to attempt measurement of the shorted magnetron. To diagnose for an open filament or high voltage. shorted magnetron. 3. Before touching any oven components, or wiring, always unplug
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NN-SD452W / NN-ST462M / NN-ST452W 3. Plug in the oven’s AC power supply cord into outlet. 5.5. Inverterpowersupply(U) 4. Program DPC. DO NOT try to REPAIR H.V. Inverter power supply For SD452W model (U).Replace complete H.V. Inverter(U) Unit. a. Press Clock button once. b. Press Timer button once. c. Press Start button once. d. Press 1000W/600W button once. For ST462M & ST452W models a. Press Timer pad twice. b. Press Start pad once. c. Press Micro Power pad once. 5. Program oven at Hi
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NN-SD452W / NN-ST462M / NN-ST452W 6 MEASUREMENTSANDADJUSTMENTS 6.1. Adjustmentofprimarylatch 6.2. Measurementofmicrowave switch, secondary latch switch output and short switch. The output power of the magnetron can be determined by performing IEC standard test procedures. However,due to the 1. Mount the Primary latch switch, the Secondary latch switch complexity of IEC test procedures, it is recommended to test and the Short switch to the door hook assembly as shown the magnetron using the simp
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NN-SD452W / NN-ST462M / NN-ST452W 7 TROUBLESHOOTINGGUIDE DANGER: HIGH VOLTAGES 1. DO NOT RE-ADJUST PRESET CONTROL on the H.V.Inverter (U). It is very dangerous to repair or adjust without proper test equipment because this circuit generates very large current and high voltage. Operating a misaligned inverter circuit is dangerous. 2. Ensure proper grounding before troubleshooting. 3. Be careful of the high voltage circuitry, taking necessary precautions when troubleshooting. 4. Discharge high vol
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NN-SD452W / NN-ST462M / NN-ST452W 7.2. (Troubleshooting)Otherproblems SYMPTOM CAUSE CORRECTIONS 1. Oven is dead. 1. Open or loose lead wire harness Fuse is OK. 2. Open thermal cutout / thermistor Check thermal cutout is defective. No display and no operation at all. 3. Open low voltage transformer 4. Defective DPC 2. No display and no operation at all. 1. Shorted lead wire harness Check adjustment of primary, secondary latch Fuse is blown. switch and short switch including door. 2. Defective pri
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NN-SD452W / NN-ST462M / NN-ST452W 7.3. Troubleshootingofinvertercircuit(U)andmagnetron This oven is programmed with a self diagnostics failure code system which will help for troubleshooting. H95, H97, H98 and H99 are the provided failure codes to indicate magnetron and inverter circuit problem areas. This section explains failure codes of H95, H97, H98 and H99. First, you must program the DPC into TEST MODE, For SD452W model: press Clock button once → press Timer button once → press Start butto
