NN-GD462M / NN-GD452W / NN-GT462M 2 DESCRIPTION OF OPERATING SEQUENCE 2.1. Variable power cooking 2.4. Grill cooking control control Grill cooking is accomplished by upper heaters only. One grill cooking cycle is 33 seconds. High Voltage Inverter Power Supply (U) controls output power by the signal from Digital Programmer Circuit (DPC).
NN-GD462M / NN-GD452W / NN-GT462M 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.
NN-GD462M / NN-GD452W / NN-GT462M 3 CAUTIONS TO BE OBSERVED WHEN 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.
NN-GD462M / NN-GD452W / NN-GT462M 3.6. Verification after repair Discharging the high voltage capacitors 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.
NN-GD462M / NN-GD452W / NN-GT462M 4 DISASSEMBLY AND PARTS REPLACEMENT 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.
NN-GD462M / NN-GD452W / NN-GT462M 4.5. Door assembly 1. Support the door, remove 3 screws holding hinge A. 4.3. Low voltage transformer 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.
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NN-GD462M / NN-GD452W / NN-GT462M 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.
NN-GD462M / NN-GD452W / NN-GT462M 4.6. Turntable motor 4.7. Quartz heater 1. Remove the motor cover by breaking off at the 8 spots 1. Disconnect lead wires from both side of heater terminals. indicated by arrows with a cutter or the like.
NN-GD462M / NN-GD452W / NN-GT462M 4.8. Steam sensor 4. Remove the heater by pulling it out from the cavity left side. 1. Disconnect connector CN2 from digital programmer circuit board. 2. Disengage catch hooks on sensor cover C from orifice.
NN-GD462M / NN-GD452W / NN-GT462M 4.9. Inverter power supply 6. Remove 1 screw holding H.V.Inverter to Inverter bracket. CAUTIONS 1. Always leave the grounding plate in place. 2. Always securely tighten the ground screw through the bottom of the chassis (base).
NN-GD462M / NN-GD452W / NN-GT462M 5 COMPONENT TEST PROCEDURE 5.3. Magnetron WARNING 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.
NN-GD462M / NN-GD452W / NN-GT462M 5.5. Inverter power supply (U) 3. Plug in the oven’s AC power supply cord into outlet. 4. Program DPC. DO NOT try to REPAIR H.V. Inverter power supply For GD462M & GD452W model (U).Replace complete H.V. Inverter(U) Unit.
NN-GD462M / NN-GD452W / NN-GT462M 6 MEASUREMENTS AND ADJUSTMENTS 6.1. Adjustment of primary latch 6.2. Measurement of microwave 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.
NN-GD462M / NN-GD452W / NN-GT462M 7 TROUBLESHOOTING GUIDE 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.
NN-GD462M / NN-GD452W / NN-GT462M 7.2. (Troubleshooting) Other problems 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.
NN-GD462M / NN-GD452W / NN-GT462M 7.3. Troubleshooting of inverter circuit (U) and magnetron 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.
NN-GD462M / NN-GD452W / NN-GT462M 7.4. Simple way of H.V. Inverter/magnetron troubleshooting Purpose: Simple way (3/23 seconds rule) of identifying whether it’s Magnetron, Inverter, or others. Set-up: The unit under question is connected through the Ammeter as shown below. Procedure: Follow the matrix table below to identify the problem source.
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