NN-A574SF / NN-A554WF / NN-A524MF / NN-CT579S / NN-CT569M / NN-CT559W 2 DESCRIPTION OF OPERATING SEQUENCE 2.1. Variable power cooking 2.4. Thermistor control The thermistor which fixed on magnetron detects magnetron temperature and make power down when the temperature High Voltage Inverter Power Supply (U) controls output power becomes abnormal high.
NN-A574SF / NN-A554WF / NN-A524MF / NN-CT579S / NN-CT569M / NN-CT559W 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-A574SF / NN-A554WF / NN-A524MF / NN-CT579S / NN-CT569M / NN-CT559W 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.
NN-A574SF / NN-A554WF / NN-A524MF / NN-CT579S / NN-CT569M / NN-CT559W 5 COMPONENT TEST PROCEDURE 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.
NN-A574SF / NN-A554WF / NN-A524MF / NN-CT579S / NN-CT569M / NN-CT559W 5.5. Inverter power supply (U) d. Press Micro Power pad once. DO NOT try to REPAIR H.V. Inverter power supply 5. Program oven at High power for 1 minute and press [Start] (U).Replace complete H.V.
NN-A574SF / NN-A554WF / NN-A524MF / NN-CT579S / NN-CT569M / NN-CT559W 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.
NN-A574SF / NN-A554WF / NN-A524MF / NN-CT579S / NN-CT569M / NN-CT559W 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-A574SF / NN-A554WF / NN-A524MF / NN-CT579S / NN-CT569M / NN-CT559W 7.2. (Troubleshooting) Other problems SYMPTOM CAUSE CORRECTIONS 1. Oven is dead. 1. Open or loose lead wire harness Check thermal cutout is defective. Fuse is OK. 2. Open thermal cutout / thermistor No display and no operation at all.
NN-A574SF / NN-A554WF / NN-A524MF / NN-CT579S / NN-CT569M / NN-CT559W 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.
NN-A574SF / NN-A554WF / NN-A524MF / NN-CT579S / NN-CT569M / NN-CT559W 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.
NN-A574SF / NN-A554WF / NN-A524MF / NN-CT579S / NN-CT569M / NN-CT559W 8.2. PARTS LIST NOTE: 1. When ordering replacement part(s), please use part number(s) shown in this part list. Do not use description of the part. 2. Important safety notice: Components identified by mark have special characteristics important for safety.
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NN-A574SF / NN-A554WF / NN-A524MF / NN-CT579S / NN-CT569M / NN-CT559W Ref. No. Part No. Part Name & Description Pcs/Set Remarks Z605A7X50BP THERMISTOR U Z490S7X50BP CONVECTION FAN MOTOR Z40087X50BP PULLEY B Z402L7X50BP FAN CASE UNIT Z22397X50BP CONVECTION FAN Z41327X50BP PULLEY A...
NN-A574SF / NN-A554WF / NN-A524MF / NN-CT579S / NN-CT569M / NN-CT559W 8.3. DOOR ASSEMBLY Ref. No. Part No. Part Name & Description Pcs/Set Remarks Z30185Q00AP DOOR KEY A Z302A7X50SBP DOOR A (U) A574SF BXQ,CT579S BPQ Z302A7X50SEP DOOR A (U) CT579S EPG...
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