ORDER NO.PAPMOSH1901008CE E1 Microwave Oven NN-GN68KS APH (USA) © Panasonic Appliances (Shanghai) Co., Ltd. 2019.
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NN-GN68KS CONTENTS Page Page 1 SCHEMATIC DIAGRAM 5 5.3. Magnetron 17 2 DESCRIPTION OF OPERATING SEQUENCE 6 5.4. Inverter power supply (U) 18 2.1. Variable power cooking control 6 5.5. Temperature thermistor 18 2.2. Inverter power supply circuit 6 2.3. Inverter defrost 6 2.4. Grill cooking control 6 2.5. Combination Cooking 6 2.6. Sensor cooking 7 2.7. Sensor reheat 7 2.8. Steam sensor and digital programmer circuit 8 6 MEASUREMENTS AND ADJUSTMENTS 19 6.1.
NN-GN68KS 1 SCHEMATIC DIAGRAM 5
NN-GN68KS 2 DESCRIPTION OF OPERATING SEQUENCE 2.1. Variable power cooking control 2.3. When the Auto Control feature is selected and the Start button is tapped: High Voltage Inverter Power Supply (U) controls output power by the signal from Digital Programmer Circuit (DPC). Power relay always stay on, but PWM (Pulse Width Modulation) signal controls microwave output power. 1.
NN-GN68KS 2.6. Explanation of the Auto Sensor Cooking process Sensor cooking 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. Auto sensor cooking without setting a power level or selecting a time. All that is necessary is to select an Auto Sensor Program before starting to cook.
NN-GN68KS NOTE: When "More" or "Less" pad is selected, the K factor varies resulting in T2 time to be increased or decreased. Example of calculating the T2 time Example 1: If the T1 time is measured to be 2 minutes and 40 seconds after the 10 second period. T2 = T1 × K - 150 sec. = 2 min. and 40 sec. × 1.1 - 150 sec. = 160sec. × 1.1 - 150 sec. = 26 sec. Category P1 P2 Power Power Sensor Reheat Power Level P7 Power Level P7 2.8.
NN-GN68KS 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. CAUTION Servicemen should remove their watches and rings whenever working close to or replacing the magnetron. 3.1. Check the grounding Do not operate on a two wire extension cord. The microwave oven is designed to be grounded when used.
NN-GN68KS Discharging the high voltage capacitors 3.6. WARNING Verification after repair There is high voltage present with high current capabilities in the circuits of the primary and secondary windings, choke coil and heat sink of the inverter. It is extremely dangerous to work on or near these circuits with the oven energized. DO NOT measure the voltage in the high voltage circuit including the filament voltage of the magnetron. 1.
NN-GN68KS 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. 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.
NN-GN68KS 4.5. Door assembly 1. Support the door, remove 3 screws holding hinge A. 4.3. Low voltage transformer and/or power relays (RY1) CAUTION: Be sure to ground any static electric charge built up in your body before handling the DPC. 2. Open the door, remove door(U) and hinge A from cavity. NOTE: 1. Replace D.P.C. board. Support the door before opening.
NN-GN68KS 9. Tighten 2 mounting screws. 6. Replace other components. 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.
NN-GN68KS 4.6. Turntable motor 4.7. 1. Remove the motor cover by breaking off at the 8 spots indicated by arrows with a cutter or the like. Quartz heater 1. Disconnect lead wires from both side of heater terminals. 2. Remove 2 screws holding upper heater panel to remove it. 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. 2. Disconnect 2 lead wires connected to the turntable motor. 3.
NN-GN68KS 4.8. 4. Remove the heater by pulling it out from the cavity left side. Steam sensor 1. Disconnect connector CN2 from digital programmer circuit board. 2. Disengage catch hooks on sensor cover C from orifice. 3. Remove steam sensor from orifice. NOTE: When installing the steam sensor, make sure that the direction of steam sensor is as shown in figure.
NN-GN68KS 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). 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. Remove the H.V.
NN-GN68KS 5 COMPONENT TEST PROCEDURE 5.3. WARNING 1. High voltage is present at the output terminals of the High Voltage Inverter (U) including aluminum heat sink during any cook cycle. 2. It is neither necessary nor advisable to attempt measurement of the high voltage. 3. Before touching any oven components, or wiring, always unplug the power cord and discharge the high voltage capacitors (see page 8). 5.1. Continuity checks can only indicate an open filament or a shorted magnetron.
NN-GN68KS 5.4. Inverter power supply (U) 5. Program oven at High power for 1 minute and press [Start] button. DO NOT try to REPAIR H.V. Inverter power supply (U). Replace complete H.V. Inverter(U) Unit. a. After approximately 3 seconds, oven stops operating. b. During oven operation, approximately 0.4A. Unplug CN701 the INPUT CURRENT 0.4A input current is FAILURE CODE Oven stops in 3 seconds after started. If both a and b check OK, the Inverter Power Supply (U) can be determined to be OK. 5.5.
NN-GN68KS 6 MEASUREMENTS AND ADJUSTMENTS 6.1. Adjustment of primary interlock switch, secondary interlock switch and interlock monitor switch. 1. Mount the Primary Interlock Switch, the Secondary Interlock Switch and the Interlock Monitor Switch to the door hook assembly as shown in illustration. 6.2. NOTE: No specific individual adjustments during installation of the Primary Interlock Switch, Secondary Interlock Switch or Interlock Monitor Switch to the door hook are required.
NN-GN68KS 7 PROCEDURE FOR MEASURING MICROWAVE ENERGY LEAKAGE 7.2.1. Measurement with the outer panel removed. Whenever you replace the magnetron, measure for radiation leakage before the outer panel is installed and after all necessary components are replaced or adjusted. Special care should be taken in measuring around the magnetron. NOTE: 7.2.2. The U.S. Government standard is 5 mW/cm2 while in the customer’s home. 2mW/cm2 stated here is our own voluntary standard.
NN-GN68KS 7.4. At least once a year, have the radiation monitor checked for calibration by its manufacturer.
NN-GN68KS 8 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. 2. Ensure proper grounding before troubleshooting. 3. Be careful of the high voltage circuitry, taking necessary precautions when troubleshooting. 4. Discharge high voltage remaining in the H.V.
NN-GN68KS 8.1. (Troubleshooting) Oven stops operation during cooking SYMPTOM 1. Oven stops in 3 seconds pressing [Start] button CAUSE CORRECTIONS after No 120V AC is supplied to H.V.Inverter (U) CN702 1. Interlock Switch terminals 2. Power relay RY1 3. Loose lead wire connector CN701, CN702 4. H.V. Inverter (U) Oven stops in 23 seconds after H.V.Inverter (U) operates by the control signals 1. Magnetron pressing [Start] button from DPC but magnetron is not oscillating 2.
NN-GN68KS 8.2. (Troubleshooting) Other problems SYMPTOM 1. Oven is dead. Fuse is OK. No display and no operation at all. 2. No display and no operation at all. Fuse is blown. 3. Oven does not accept key input (Program) 4. Fan motor turns on when oven is plugged in with door closed. 5. Timer starts count down but no microwave oscillation. (No heat while oven lamp and fan motor turn on) 1. 2. 3. 4. 1. 2. 3. 4. 1. 2. 1. 2. 3. 1. 2. 3. 6. Oven can program but timer does not start countdown. 7.
NN-GN68KS 8.3. 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. First, you must program the DPC into TEST MODE, press Timer/Clock button twice → press Start button once → press Power Level button once.
NN-GN68KS 8.4. Trouble related to Digital Programmer Circuit SYMPTOM No display when oven is first plugged in STEP CHECK 1 Fuse pattern of D.P.C., FUSE1 2 3 No key input 1 No beep sound 1 No microwave oscillation at any power 1 2 3 Dark or unclear display 1 Missing or lighting of unnecessary segment 1 H95/H97/H98 appears in window and oven stops operation.
NN-GN68KS 8.5. 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. Note: Do not replace both Inverter board and Magnetron simultaneously and automatically without going through this procedure. Power will: Ammeter reading is: Shut off in 23 seconds 1.
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NN-GN68KS 9 EXPLODED VIEW AND PARTS LIST 9.1.
NN-GN68KS 9.2. 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. When replacing any of these components, use only manufacture’s specified parts. Ref. No. 1 3 4 5 Part No.
NN-GN68KS Ref. No. 62 65 66 Part No.
NN-GN68KS 9.3. ESCUTCHEON BASE ASSEMBLY Ref. No. E1 E2 E3 E4 Part No. F603LCB00AP F603YCB00AP F800LCB00SAP F891PCA00SAP Part Name & Description D.P.CIRCUIT (AU) D.P.
NN-GN68KS 9.4. DOOR ASSEMBLY Ref. No. D1 D2 D3 D4 D5 Part No.
NN-GN68KS 9.5. Ref. No. W1 W2 WIRING MATERIALS Part No. F030ACB00AP F030ECA50CP Part Name & Description LEAD WIRE HARNESS H.V.
NN-GN68KS 9.6. PACKING AND ACCESSORIES Ref. No. P1 P2 P3 P4 P5 Part No. F0003CB00AP F0102CB00SAP F01049Y00AP F01059Y00AP F01067F00AP Part Name & Description INSTRUCTION MANUAL PACKING CASE,PAPER UPPER FILLER LOWER FILLER P.E.
NN-GN68KS 10 DIGITAL PROGRAMMER CIRCUIT 10.1.
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NN-GN68KS 10.2. PARTS LIST Ref. No. BZ210 LCD110 DISP HOLDER VA1 IC1 IC10 IC25 IC480 PC25,PC26 RL1,RL3,RL4 RL2 T10 SW1,SW2,SW4,SW6,SW7,SW9-SW23 FUSE1 Part No. L0DDEA000014 L5AYAYY00424 F6617CA10QP F67525E20XN D4EAY2710001 MNCA2F50ABS C0DBGYY05981 C0DAZYY00046 C0ABBA000230 B3PAA0000302 K6B1AYY00129 K6B1AGA00193 G4DYA0000894 K0H1BA000691 K5G402YA0159 Part Name & Description BUZZER LCD LCD HOLDER DIFFUSION SHEET VARISTOR L.S.I.
