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Panasonic NN-CT890SBPQ, Service Manual, Page: 35 / 45

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Panasonic NN-CT890SBPQ Service Manual Download Page 35

NN-CT890SBPQ

35

6A5BPQ

Other problems

                                

Inverter circuit troubleshooting

Alternate way to troubleshoot oven with AC Ampere meter used

H95, H97, H98, H99 appears in display window a short time after start key is pressed and no microwave oscillation with AC Ampere
meter used for troubleshooting.

                       

Alternative method for toubleshooting, the inverter circuit

Summary of Contents for NN-CT890SBPQ

Page 1: ...HAD1003001C2 Microwave Oven NN CT890SBPQ 32L United Kingdom Panasonic Home Appliance Division 2010 Unauthorized copying and distribution is a violation of law ...

Page 2: ...bleshooting Guide 33 14 Exploded View 36 15 Parts List 37 16 Door Assy 39 17 Escutcheon Base 40 18 Packing and Accessories 41 19 Trim Kit 44 20 Digital Programmer Circuit 44 21 Key Board Matrix 45 Power source 230V 240V AC Single Phase 50Hz Power requirements Microwave 1200W Grill 1560W Convection 1300W Combi 2700W Output IEC60705 Microwave 1000W Grill 1500W Convection 1250W Microwave frequency 24...

Page 3: ...rter PCB as this can be very dangerous Replace the high voltage inverter circuit as a complete unit Return the old unit fully repacked in the original shipping box and completed paper work 4 Do not adjust or tamper with the preset volume on the inverter board It is very dangerous to adjust this preset without proper test equipment 5 Do not test the oven while the inverter grounding strip or screws...

Page 4: ...king the door is opened or Stop Cancel Pad is pressed once Start Pad has to be pressed again to continue cooking 16 Stop Cancel Pad Before Cooking one press clears your instructions During Cooking one press temporarily stops the cooking program Another press cancels all your instructions and the time of day will appear in the display 3 Beep Sound A beep sounds when a pad is pressed If this beep do...

Page 5: ...r Levels except HIGH power the maximum time that can be set is 99 minutes 50 seconds The 1h pad is inoperable Press Start inoperable G Press Timer Pad twice Colon starts to blink SET TIME will appear in the display window G Press Time Pads Enter time of day by pressing Time Pads e g 13 pm 24hr clock G Press Timer Pad Colon stops blinking Time of day is now locked into the display Press thirteen ti...

Page 6: ...f no food has been placed inside the oven or a cooking time set then it will automatically cancel the cooking program and revert to time of day There is no pre heat at 40 C inoperable 10 min 1 min 10 sec 1 h Grill 1 2 3 Start Grilling Start Select Grill power Press once for Grill 1 High twice for Grill 2 Medium or three times for Grill 3 Low The Grill symbol will appear Press Start to preheat P wi...

Page 7: ...hen to 100 C 110 C etc Grill and Convection symbols will appear Press to select Grill power if you wish to adjust from Grill 3 Low to select Grill 1 High or Grill 2 Medium Press Start to preheat P will appear in the display window When the oven is preheated the oven will beep and the P will flash Then open the door and place the food inside 10 min 1 min 10 sec 1 h Start Press Time Pads to enter co...

Page 8: ... Micro Power Pad to select Microwave setting HIGH DEFROST are not available Press to enter required cooking time 10 sec pad is inoperable Press Start Pad Combination 2 Grill and Microwave This Combination mode is suitable for foods which are normally grilled and for reheating small savoury items Do not use this program with less than 200 g 7 oz of food It is necessary to preheat when using this Co...

Page 9: ...heat and food should always be cooked uncovered 10 min 1 min 10 sec 1 h Turbo Bake Grill 1 2 3 Micro Power Start Combination Press Combination Pad Press to select oven temperature The oven starts at 150 C and then for each press the temperature will count up in 10 C stages to 250 C then to 100 C 110 C etc Press to select Grill Power if you wish to adjust from Grill 3 Low to Grill 1 High or Grill 2...

Page 10: ...NN CT890SBPQ 10 6 Schematic Diagram ...

Page 11: ...NN CT890SBPQ 11 7 Wiring Diagram Wiring Harness ...

Page 12: ...ow Duty cycles for Grill Cooking 8 3 Auto weight defrost Auto weight Cook When an auto control feature is selected and the start pad pressed 1 The digital programmer circuit determines the power level and the cooking time and indicates the operating state in the display The table shows the corresponding cooking times for each category and its respective weight 2 When the cooking time in the displa...

Page 13: ...ng power to relay RY5 resulting in the convection heater turning off 3 When the temperature drops below the predetermined temperature the digital programmer circuit supplies power to power relay RY5 resulting in the convection heater turning on Note After the convection process if the oven tempera ture is higher than the predetermined temperature the fan motor rotates to cool the electronic compon...

Page 14: ...RY5 switching on the heater elements In the case of grill combination the sequence applies with the digital programmer circuit switching power relay RY4 to con trol the grill elements With convection grill and micro power combination The grill elements and convection elements are operated alternatively whilst the oven temperature is above the selected level Convection Microwave Combination Convect...

Page 15: ...NN CT890SBPQ 15 8 5 1 convection and microwave duty cycles Figure 1 ...

Page 16: ...NN CT890SBPQ 16 8 5 2 grill and microwave duty cycles Figure 2 ...

Page 17: ...s from the container In auto sensor cooking a carefully designed instrument called the humidity sensor element senses the escape of steam then based upon the auto sensor program selected the unit will automatically determine the correct power level and the proper length of time it will take to cook the food NOTE Auto sensor cooking is successful with the foods and recipes found in the auto sensor ...

Page 18: ...ger in ordinary use extreme care should be taken during repair As you can see it looks like a TV flyback transformer however the current is extremely large and is therefore dangerous due to this high current and high voltage The aluminium heat sink is also energized with high voltage HOT so do not touch when the AC input terminal is con nected The power devices Collector is directly connected to t...

Page 19: ...scharge Please be sure to touch the chassis ground side first and then short to the output terminals WARNING 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 circ...

Page 20: ...ter repair or replacement of parts make sure that the screws of the oven etc are neither loose nor missing Microwaves might leak if screws are not properly tight ened 2 Make sure that all electrical connections are tight before inserting the plug into the wall outlet 3 Check for microwave energy leakage Refer to proce dure for measuring microwave energy leakage CAUTION MICROWAVE RADIATION DO NOT B...

Page 21: ...g the magnetron as shown in figure 2 NOTE After replacing the magnetron tighten the mount ing screws making sure that there is no gap between the waveguide and the magnetron to prevent microwave leak age Caution When replacing the magnetron ensure that the antenna gasket is in place Note The magnetron used for this model is unique for the inverter power supply system Make sure to use the magnetron...

Page 22: ...ort 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 Make sure that grounding plate is in place 2 Securely tighten the grounding screw through the side of the chassis Base 3 Securely connect the 3 lead wire connectors 4 Make sure that the heat sink ha...

Page 23: ... with double faced adhesive tape Therefore apply ing hot air such as using a hair dryer is recommended for smoother removal 2 When installing a new escutcheon key board make sure that the surface of the escutcheon base is cleared suffi ciently so that problems such as shorted contacts and uneven surfaces can be avoided 10 4 Low voltage transformer and or power relays Note Be sure to ground your bo...

Page 24: ...ove the door key and spring from the door E After replacement of the defective component parts of the door reassemble it and follow the instructions below for proper installation and adjustment so as to prevent exces sive microwave leakage 1 When mounting the door to the oven be sure to adjust the door parallel to the bottom line of the oven face plate by moving the upper hinge in the direction ne...

Page 25: ... 10 3 Disconnect the cables to the grill heater 4 Remove the grill cover by removing the 5 screws in figure 11 5 Remove the two screws holding the grill heater Figure12 6 Loosen the 2 screws holding the ceramic grill holders turn the holders to release the grill element 7 Remove the heater bracket D by using a flat blade screw driver to lever back the tabs 8 The grill element can now be removed fr...

Page 26: ...NN CT890SBPQ 26 Removing the screws holding the grill heater Figure 11 Removing the grill element Figure 12 ...

Page 27: ...Remove the power cord 5 Remove the wire terminals from the circulation fan motor and the convection heater element 6 Remove the four screws from the oven base Figure 15 7 Carefully place the oven onto its base and remove the backplate 8 Remove the nut holding the circulation fan Figure 16 9 Remove the circulation fan by removing the three screws Figure 16 10 Remove the convection element by removi...

Page 28: ...NN CT890SBPQ 28 Removing the oven back plate Figure 14 Removing the base plate Figure 15 ...

Page 29: ...NN CT890SBPQ 29 Removing the circulation motor Figure 16 ...

Page 30: ... Monitor Cir cuit 1 Unplug the lead wires from the HV inverter primary termi nals 2 Connect the test probes of the ohm meter to these leads 3 Test the continuity of the short switch with the door open and the door closed using the lowest ohm scale 11 3 Magnetron Continuity checks can only indicate an open filament or a shorted magnetron To diagnose an open filament or shorted magnetron 1 Isolate t...

Page 31: ...the rear of the oven The resistance reading across the thermistor should read 300K ohm within a temperature range of 10 to 30 degrees centigrade This would be the temperature range within a kitchen environment If the resistance measured is outside this range the thermistor is defective and should be replaced NOTE When measuring the resistance of the thermistor dis connect the connector from the di...

Page 32: ...ment is completed Completely tighten the screws holding the door hook assembly to the oven assembly 3 Reconnect the short switch primary switch and second ary latch switches and check the continuity of the monitor circuit and latch switches by following the component test procedures on page 29 12 2 Measurement of microwave output The output power of the magnetron can be determined by per forming t...

Page 33: ...NN CT890SBPQ 33 13 Troubleshooting Guide ...

Page 34: ...NN CT890SBPQ 34 Fuses are not blown Fuses are blown Checking the semiconductors using a resistance meter ...

Page 35: ...ternate way to troubleshoot oven with AC Ampere meter used H95 H97 H98 H99 appears in display window a short time after start key is pressed and no microwave oscillation with AC Ampere meter used for troubleshooting Alternative method for toubleshooting the inverter circuit ...

Page 36: ...NN CT890SBPQ 36 14 Exploded View ...

Page 37: ...P CAM A 1 22 E61425180AP SHUTTER SWITCH 1 23 E22439000BP ADIABATIC MATERIAL A 1 24 E40447P00BP INVERTER AIR GUIDE 1 26 E40307M30BP AIR GUIDE D 1 27 E030E4V20BP HV LEAD WIRE 1 28 E606YM300XN INVERTER 1 29 E66017P00BP INVERTER EARTH BRACKET 1 30 E65857H83BP INVERTER SUPPORT BRACKET 1 31 E10214V20UP ADAPTER PLATE 1 32 E610T6700BP OVEN LAMP 1 33 E603Y7X80BP PCB DU 1 34 E030C6R20BP ADAPTER LEADWIRE 1 3...

Page 38: ...1 E41079000GP EXHAUST GUIDE B 1 72 E09230000AQ CUSHION RUBBER 1 73 E490S8020GP CONV MOTOR 1 74 E22399000GP CIRCUALTION FAN 1 75 E110D4V30SBP OUTER PANEL 1 76 E01507550BP WARNING LABEL 1 77 E090900BCAN BASEPLATE CUSHION 2 78 E09230000AN CUSHION 1 Ref No Part No Part Name Description Qty ...

Page 39: ...er door C this part may become damaged during disassembly of the door Ref No Part No Part Name Description Qty D1 E302A7X80SBP DOOR A ASSEMBLY 1 D2 E30214000AP DOOR KEY SPRING 1 D3 E30188000BP DOOR KEY A 1 D4 E302K7X80BP DOOR E 1 D5 E30859000BP DOOR C 1 D6 E30067300AP HINGE 1 ...

Page 40: ... Au 1 E7 E60707P20BP Insulation Sheet 1 E8 E83097P01BP Pcb Spacer 1 E9 E605S7X80BP Pcb Hu 1 E10 E82564V20BP Door Opening Lever 1 E11 E80378A0AG Door Opening Button Spring 1 E12 E80727P00SBP Door Opening Button 1 E13 E63837X80BP Membrane Switch 1 E14 E800S7X80SBP Escutcheon Base 1 E15 E00077X80SBP Name Plate 1 NOTE When ordering a new Escutcheon base E14 also order a nameplate E15 Write the model n...

Page 41: ...E06435870SP RUBBER FOOT BLACK 3 P4 E060V5870SP WIRE RACK HIGH 1 P5 E06016A50BP SQUARE ENAMEL TRAY 1 P6 E06026A50BP SQUARE WIRE RACK 1 P7 E06014N30BP GLASS TRAY 1 P8 E06015020VP ENAMEL TRAY 1 P9 E290D5850GP ROLLER RING 1 P10 E06485020AP SPATTER SHEILD 1 P11 E00037X80BP OPERATING INSTRUCTIONS 1 P12 E01024V20BP CARTON BOX 1 P13 E01056A50BP LOWER FILLER 1 ...

Page 42: ...NN CT890SBPQ 42 P14 E01069000BP COVER POLYTHENE 1 P15 E01079000BP DOOR SHEET 1 P16 E01926430GP PROTECTOR SHEET 1 P17 E01049000BP UPPER FILLER 1 Ref No Part Number Part Name Description Qty ...

Page 43: ...del Number Part Name Set Description NN TKA80W E1603A510HBP 1 Top And Bottom Strip REF No 1 NN TKA80M E1603A510NBP 1 Top And Bottom Strip REF No 1 NN TKA80W E1601A540HBP 1 Side strip REF No 2 NN TKA80M E1601A540NBP 1 Side strip REF No 2 A0003A810BP Installation Guide ...

Page 44: ...NN CT890SBPQ 44 20 Digital Programmer Circuit ...

Page 45: ...A B 2 A 1 I 9 AUTO MENU 6 C 13 CASSEROLE 14 MEAT SAUCE J 10 AUTO MENU 7 C 15 POTATO CRISPY TOP 16 PASTA CRISPY TOP K 11 AUTO MENU 8 C 17 WHOLE CHICKEN 18 CHICKEN PIECES WITH BONE 19 CHICKEN PIECES BONELESS L 12 AUTO MENU 9 C 20 BAKE FRUIT CRUMBLE 21 BAKE CAKE M 13 㧙 㧙 N 14 1 HOUR C O 15 10 MIN C P 16 10 SEC C Q 17 1 MIN C R 18 㧙 㧙 S 19 MICRO POWER C T 20 CONVECTION C U 21 COMBINATION 㧙 V 22 TIMER ...

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