Panasonic NN-A880WB Service Manual
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Panasonic NN-A880WB Service Manual

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Order Number MOP00090015C2
Microwave Oven
NN-A880WB / NN-A850WB / NN-A850CB
SPECIFICATIONS
1995 Matsushita Electric Industrial Co., Ltd. All rights reserved.
Unauthorized copying and distribution is a violation of law.
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Summary of Contents for Panasonic NN-A880WB

  • Page 1 Order Number MOP00090015C2 Microwave Oven NN-A880WB / NN-A850WB / NN-A850CB SPECIFICATIONS 1995 Matsushita Electric Industrial Co., Ltd. All rights reserved. Unauthorized copying and distribution is a violation of law.

  • Page 2: Inverter Warning

    1. Inverter Warning The inverter board looks like a regular PCB, however, this PCB drives the magnetron tube using very high voltages and current. It has 1. Very high voltage and high current 2. An Aluminium heat sink that becomes very hot 3.

  • Page 3: Feature Chart

    Inverter Gounding Figure 2 Inverter PCB layout 2. Feature Chart Function NN-A880WB NN-A850WB NN-A850CB Microwave Grill Convection Combination Sensor reheat Sensor cook Sensor combination Weight defrost Weight combination Weight reheat Weight cook Stage cooking Delay/Stand More/Less Kg-> lb/oz Clock Word prompt...
  • Page 4 3. Control Panel 4. Operation And Digital Programmer Circuit Test Procdure...

  • Page 7: Schematic Diagram

    5. Schematic Diagram...

  • Page 8: Wiring Diagram

    6. Wiring Diagram 7. Description of Operating instruction 7.1. Variable power cooking control The HIGH VOLTAGE INVERTER POWER SUPPLY controls the output power by a signal from the digital Programmer circuit DPC. The power relay (RY1) turns on to supply power to the inverter circuit.

  • Page 9: Grill Cooking

    Note: After auto cooking if the oven temperature is over the predetermined temperature the fan motor rotates to cool the oven and its components. Auto Weight Defrost NN-A880WB NN-A850WB NN-A880CB Category 1st Touch Cooking Weight...
  • Page 10 Category 1st Touch Cooking Weight Time 9.Whole Chicken 1000 18m 20s 10.Chicken Portions 9m 30s 11.Beef/Lamb 14m 40s 12.Casserole 56m 40s 13.Chilled Crispy Top 14.Frozen Crispy Top 15.Bake Pastry 16.Bake Cake 11m 40s Auto weight Cook NN-A850WB NN-A850CB Category 1st Touch Cooking Weight Time...

  • Page 11: Combination Cooking

    power relay RY5 resulting in the convection heater turning on. Note: After the convection process, if the oven temperature is higher than the predetermined temperature, the fan motor rotates to cool the electronic components and the oven. Figure 1 Convection Cooking Duty Cycles 7.5.
  • Page 12 Convection Heater Micropower 100 - 250 C OUTPUT ON Medium 600W 440W Simmer 440W Warm 440W Grill And Microwave Combination Duty Cycles Grill Heater Micropower OUTPUT ON Grill 1 Medium 600W Grill 2 440W Grill 3 30 Simmer 440W Warm 440W Grill Convection And Microwave Combination Duty Cycles Convection Grill Heater...
  • Page 13 Convection and microwave duty cycles Figure 2 Grill and microwave duty cycles...
  • Page 14 Grill,Convection and microwave duty cycles 7.6. One touch Auto sensor cooking NN-A880WB Auto sensor cook is a revolutionary way to cook by microwave without setting a power level or selecting a time. All that is necessary is to select an auto sensor program before starting to cook.

  • Page 15: Cautions To Be Observed When Troubleshooting

    time is then shown in the display and begins counting down. Balance of cooking (T2 time) The balance of cooking time which is called T2 time, can be calculated by the following formula. / T2 time (in sec.) = T1 time x K factor NOTE: Remember, the T1 time starts after the start pad is tapped.
  • Page 16 grounded. It is imperative, therefore, to ensure the appliance is properly grounded before beginning repair work. 8.2. Inverter Warnings DANGER, HIGH VOLTAGE AND HIGH TEMPERATURE (HOT/LINE) OF THE INVERTER POWER SUPPLY (U) This high voltage inverter power supply handles very high voltage and very high current for the magnetron tube.
  • Page 17 Inverter Grounding WARNING! DISCHARGE THE HIGH VOLTAGE CAPACITORS For about 30 seconds after the oven is turned off, an electric charge remains in the high voltage capacitors in the inverter power supply circuit board. When replacing or checking parts, remove the power plug from the outlet and short the inverter output terminal of the magnetron filament terminals to the chassis ground with an insulated handle screwdriver to discharge.
  • Page 18 in the high voltage circuit including the filament voltage of the magnetron. WARNING Never touch any circuit wiring with your hand nor with an insulated tool during operation. 8.3. When parts must be replaced, remove the power plug from the outlet.

  • Page 19: Parts Replacement Procedure

    MICROWAVE GENERATOR OR OTHER PARTS CONDUCTING MICROWAVE ENERGY IMPORTANT NOTICE The following components have potentials above 250V while is appliance is operated. - Magnetron - High voltage transformer (Located on inverter (U)) - High voltage diodes (Located on inverter (U)) - High voltage capacitors (Located on inverter (U)) Pay special attention in these areas.
  • Page 20 Figure 1 Removal of the magnetron Figure 2 Screws to remove the magnetron 9.2. Inverter power supply (U) 1. Discharge the high voltage capacitors 2. Unplug the H.V. Lead wires from the magnetron 3. Remove the connector CN701 and CN702 from the inverter PCB 4.
  • Page 21 6. Carefully remove the inverter PCB and support base from the oven. 7. Remove the air guide E by un-clipping the catch hooks 8. Remove the four screws holding the PCB to the inverter support base. Caution when replacing the inverter power supply (U) 1.
  • Page 22 1. Disconnect all connectors from the DPC. 2. Remove the four screws holding the escutcheon base and slide the escutcheon base upward slightly. removal is easier with the door open. 3. Release the flat cable. 4. Remove the six screws holding the DPC DU assembly 5.
  • Page 23 9.4. Low voltage transformer and/or power relays Note Be sure to ground your body to discharge any static before handling the DPC. 1. Using a solder wick or a de soldering tool and a 30W soldering iron, carefully remove all solder from the terminal pins of the low voltage transformer and/or power relays.
  • Page 24 Removing the fan motor 9.6. Door disassembly 1. Remove door C from door E by carefully pulling outward starting from the upper right hand corner using a flat blade screwdriver. 2. Remove four screws holding the door E to the door A assembly 3.

  • Page 25: Turntable Motor

    Disassembly of the door 9.7. Turntable Motor 1. Remove the motor cover by breaking off at the 8 spots indicated by the arrows. 2. Disconnect the two lead wires connected to the turntable motor 3. Remove the turntable motor by removing the two screws Note: After breaking off the motor cover, make sure that cut-off portions are properly trimmed off or bent inside so that no sharp edges are exposed.
  • Page 26 Two screws to remove the turntable motor 9.8. Quartz Heater 1. Remove the sensor cable from the DPC connector CN7. 2. Remove the exhaust guide A by removing the two screws shown in figure 10. 3. Disconnect the cables to the grill heater 4.
  • Page 27 Removing the screws holding the grill heater Figure 12 Removing the grill element 9.9. Convection Element And Circulation Fan Motor 1. Remove one screw to remove the the exhaust guide D. Figure 13. 2. Remove the rear heater cover by removing the three screws. Figure 13 3.
  • Page 28 10. Remove the convection element by removing the two screws. Figure 16 Figure 13 Removing the rear heater cover Figure 14...
  • Page 29 Removing the oven back plate Figure 15 Removing the base plate Figure 16...

  • Page 30: Component Test Procedure

    Removing the circulation motor 10. Component Test Procedure Caution 1. High voltage is present at the high voltage terminal of the inverter unit, including the aluminium heat sink. 2. It is not necessary or advisable to attempt to measure this high voltage.
  • Page 31 secondary latch switch. 3. Test the continuity of the switches with the door open and closed with an ohm meter on the lowest scale. Normal continuity readings should be as followed. Door Open Door Closed Primary Latch infinite (Close) Switch (Open) Secondary infinite...

  • Page 32: Push Button Keyboard

    10.4. Push Button Keyboard Check the continuity between the switch terminals, by tapping an appropriate pad on the keyboard. The keypad matrix is shown on . 10.5. Inverter Power Supply Caution DO NOT try to repair this inverter power supply). Replace as a whole H.V.

  • Page 33: Measurements And Adjustments

    NOTE: If the microwave oven has been operated allow to cool to room temperature before attempting to measure the thermistor resistance. 10.8. Humidity sensor and digital programmer circuit NN-A880WB 1. Check the resistance across the sensor heater terminals. Normal cold resistance should read approximately 4.5 ohms.
  • Page 34 mounting tabs are not bent, broken or otherwise deficient in their ability to hold the switches. - Refer to the schematic and wiring diagram to ensure proper connection 11.1. Installation of primary latch switch, secondary latch switch and short switch. 1.

  • Page 35: Troubleshooting Guide

    (Recorded as T2) 4. The normal temperature rise at the high power position for each model is shown in the table. (Figure 2) Figure 1 Adjustment of latch switch assembly RATED OUTPUT TEMPERATURE RISE 1000W 8°C 12. Troubleshooting Guide...
  • Page 36 Fuses are not blown Fuses are not blown...
  • Page 37 Other problems Inverter circuit troubleshooting...
  • Page 38 Alternative method for toubleshooting the inverter circuit 13. Digital Programmer Troubleshooting Guide...

  • Page 39: Exploded View

    How to check semiconductors 14. Exploded View...

  • Page 40: Main Parts List

    15. Main Parts List 1. Part numbers are indicated on most mechanical parts. Please use these part numbers for part orders. Do not use the description of the part. Important safety notice 1. Components identified by! mark have special characteristics important for safety.
  • Page 41 Ref. No. Part No. Description Remarks E00064080BP WARNING LABEL E41199000BP EXHAUST GUIDE D E10589000BP BACK PANEL COVER E605A4V20BP THERMISTER AEE9108A20GN HOLDER (P CLIP) E900C4V20BP POWER CORD SUPPLY E67597550GP FUSE 10A E607X4V20BP NOISE FILTER E400A4760JP FAN MOTOR AEE6230P10GN FUSE 16A E09020000AP CUSHION RUBBER E22369000BP RIGHT HEATER PANEL...

  • Page 42: Door Assembly

    ADIABATIC MATERIAL E20339000BP HEATER COVER B E41079000GP EXHAUST GUIDE B E09230000AQ CUSHION RUBBER E490S8020GP CONV MOTOR E22399000BP CIRCUALTION FAN E110D4V30HBP OUTER PANEL NN-A880WB NN-A850WB E110D4V30BP OUTER PANEL NN-A850CB E01507550BP WARNING LABEL NN-A880WB NN-A850WB E01507560BP WARNING LABEL NN-A850CB 16. Door Assembly...

  • Page 43: Escutcheon Base Assembly

    Part Description Remarks E302A4V20HBP DOOR A ASSYM 1 NN-A880WB NN-A850WB E302A4V20BP DOOR A ASSYM 1 NN-A850CB E30214000AP DOOR KEY SPRING E30188000BP DOOR KEY A E302K9000BP DOOR E E30859000BP DOOR C E30067300AP HINGE When ordering any door component also order door C, this part may become damaged during dissassembly of the door.

  • Page 44: Packing And Accessories

    Ref. No. Part Description Remarks E80724V20HBP DOOR OPENING BUTTON NN-A880WB NN-A850WB E80724V20BP DOOR OPENING BUTTON NN-A850CB E80378A0AG SPRING E80344V20HBP ESCUTCHEON BASE NN-A880WB NN-A850WB E80344V20BP ESCUTCHEON BASE NN-A850CB E81274V20BP ESC BACK PLATE E603L4V20BP P C B AU NN-A880WB E603L4V30BP P C B AU...
  • Page 46 ENAMEL TRAY E06485020AP SPLATTER TRAY E290D5850GP ROLLER RING E00034V20BP OPERATING INSTRUCTIONS/COOKBOOK 1 E01695750BP SERVICE LIST E01136700BP TRAY STYROL E01024V20HBP CARTON BOX NN-A880WB E01024V30HBP CARTON BOX NN-A850WB E01024V30BP CARTON BOX NN-A850CB E01059000BP LOWER FILLER E01069000BP COVER POLYTHENE E01079000BP DOOR SHEET E01926430GP...
  • Page 47 Trim Model Number Top And Bottom Strip Side strip REF No 2 Microwave Oven Model Number REF No 1 NN-TKA80W E1603A510HBP E1601A540HBP NN-A880WB NN-A850WB NN-TKA80C E1603A510BP E1601A540BP NN-A850CB Instalation Guide A0003A810BP 21. Digital Programmer Circuit Schematic...

  • Page 49: Key Board Matrix

    22. Key Board Matrix...
  • Page 50 23. Digital Programmer Circuit Parts 23.1. E603L4V20BP E603L4V30BP DPCAU...
  • Page 51 Reference Part Number Description J603L 4V20BP J603L 4V30BP C502 AECU1F101J50 100pF Chip Capacitor C40-C48 C110 C20 C441 AECU1F103Z50 10nF Chip Capacitor C570 C501 AECU1F103Z50 10nF Chip Capacitor C220 C221 C222 C224 C21 AECU1F104Z25 100nF Chip Capacitor C130, C500 AECU1F104Z25 100nF Chip Capacitor R111-R113 R20 R442 R571 AERJ3GSYJ102 1K Chip Resistor...
  • Page 52 23.2. E603Y4V20BP E603Y4V30BP DPC DU Reference Part Number Description J603Y 4V20BP J603Y 4V30BP ZD10 AESZMTZ5R6B Zener Diode D221-D225 AESS133T-77 Silicon Diode AESS133T-77 Silicon Diode D220 AESS1N4003E Silicon Diode AESSAK03 Shottky Diode C330 ECBT1H681KB5 680PF Capacitor C331 ECBT1H681KB5 680PF Capacitor C440 ECBT1E103ZF5 10nF Capacitor R25,R26...

This manual is also suitable for:

Nn-a850wbNn-a850cb

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