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2.1. Variable power cooking

control

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.

NOTE:

The ON/OFF time ratio does not correspond with the
percentage of microwave power since approximately 2
seconds are required for heating of magnetron
filament.

Variable Power Cooking

POWER

SETTING

OUTPUT

POWER(%)

APPROX.

MANUAL MICROWAVE DUTY

ON(SEC)

OFF(SEC)

1000W

100%

22

0

270W

25%

16

6

600W

60%

22

0

440W

45%

22

0

300W

30%

22

0

100W

10%

10

12

2.2. Inverter power supply circuit

The Inverter Power Supply circuit powered from the line
voltage, 230V 50Hz AC input supplies 4,000V DC to the
magnetron tube, and functions in place of the H.V. transformer,
the H.V. capacitor and H.V. diode.
 1. The AC input voltage 230V 50Hz is rectified to DC voltage

immediately.

 2. DC voltage will be supplied to the switching devices called

IGBT. These devices are switched ON-OFF by the 20 to 40
kHz PWM (pulse width modulation) signal from the
microcomputer in the DPC.

 3. This drives the High voltage transformer to increase voltage

up to 2,000V AC.

 4. Then the half-wave doubler voltage rectifier circuit,

consisting of the H.V. diodes and capacitors, generates the
necessary 4,000V DC needed for the magnetron.

 5. Output power of the magnetron tube is always monitored by

the signal output from the current transformer built into the
inverter circuit.

 6. This signal is fed back to the microcomputer in the DPC to

determine operating conditions and output necessary to
control PWM signal to the Inverter Power Supply for control
of the output power.

2.3. Turbo defrost, Auto cook

When the Auto Control feature is selected and the Start pad is
tapped:
 1. The digital programer circuit determines the power level and

cooking time to complete cooking and indicates the
operating state in the display window.

 2. When cooking time in the display window has elapsed, the

oven turns off automatically by a control signal from the
digital programmer circuit.

2.4. Grill cooking control

Grill cooking is accomplished by upper heaters only. One grill
cooking cycle is 33 seconds.
 1. During grill cooking, the digital programmer circuit controls

power relay RY4´s ON-OFF time. In all three grill cooking
categories, power relay RY1 always stay ON, but RY3 &
RY4´s ON-OFF time are shown in Figure.

GRILL

CATEGORY

GRILL (RY3 & RY4)

(RY1)

ON (sec.)

OFF (sec.)

1

33

0

ON

2

24

9

ON

3

18

15

ON

2.5. Sensor cooking

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.

Understanding Auto Sensor Cooking

As the food cooks, a certain amount of steam is produced.
If the food is covered, this steam builds up and eventually
escapes from the container. In Auto Sensor Cooking, a
carefully designed instrument, called the steam sensor
element, senses this 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 Cooking Guide.
Because of the vast differences in food composition,
items not mentioned in the Cooking Guide should be
prepared in the microwave oven using power select
and time features. Please consult Variable Power
Microwave Cookbook for procedures.

2 DESCRIPTION OF OPERATING SEQUENCE

6

NN-GD462M / NN-GD452W / NN-GT462M

Содержание NN-GD452W

Страница 1: ...onic Appliances Microwave Oven Shanghai Co Ltd 2012 NN GD462M NN GD452W NN GT462M EPG Continental Europe GPG Germany WPG Switzerland SPG Norway Finland Sweden Denmark Microwave Oven ORDER NO PAPMOSH1202017CE ...

Страница 2: ...2 NN GD462M NN GD452W NN GT462M ...

Страница 3: ...3 NN GD462M NN GD452W NN GT462M ...

Страница 4: ...5 5 COMPONENT TEST PROCEDURE 16 5 1 Primary Secondary Latch Switch interlocks Power Relay RY1 16 5 2 Short Switch 16 5 3 Magnetron 16 5 4 key board membrane Membrane switch assembly 16 5 5 Inverter power supply U 17 5 6 Temperature thermistor 17 6 MEASUREMENTS AND ADJUSTMENTS 18 6 1 Adjustment of primary latch switch secondary latch switch and short switch 18 6 2 Measurement of microwave output 18...

Страница 5: ...1 SCHEMATIC DIAGRAM 5 NN GD462M NN GD452W NN GT462M ...

Страница 6: ... power 2 3 Turbo defrost Auto cook When the Auto Control feature is selected and the Start pad is tapped 1 The digital programer circuit determines the power level and cooking time to complete cooking and indicates the operating state in the display window 2 When cooking time in the display window has elapsed the oven turns off automatically by a control signal from the digital programmer circuit ...

Страница 7: ...cessor memory and they are listed in the following tables along with the P1 and P2 powers 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 2 min and 40 sec 0 1 160sec 0 1 16 sec Category P1 Power P2 Pow...

Страница 8: ...num heat sink may be HOT due to heat energy therefore extreme care should be taken during servicing H V Inverter warning WARNING FOR INVERTER POWER SUPPLY U GROUNDING Check the High Voltage Inverter Power Supply circuit grounding The high voltage inverter power supply circuit board must have a proper chassis ground The inverter grounding plate must be connected to the chassis If the inverter board...

Страница 9: ...uring operation Never insert a wire nail or any other metal object through the lamp holes on the cavity or any holes or gaps because such objects may work as an antenna and cause microwave leakage 3 6 Verification after repair 1 After repair or replacement of parts make sure that the screws of the oven etc are neither loosen or missing Microwave energy might leak if screws are not properly tighten...

Страница 10: ... body before handling the DPC 1 Disconnect connector CN701 on H V Inverter board 2 Remove 1 screw holding escutcheon base and slide the escutcheon base upward slightly 3 Remove all screws holding D P C board on escutcheon base 4 Separate D P C board from tabs on the escutcheon base and remove D P C board To replace membrane key board 5 Use tools such as kinfe etc to lift the edge of escutcheon she...

Страница 11: ... pins are inserted completely resolder all terminal contacts carefully 4 4 Fan motor 1 Disconnect 2 lead wires from fan motor terminals 2 Remove 2 screws at location on oven attaching orifice assembly 3 Remove orifice assembly from oven assembly 4 Remove fan blade from the fan motor shaft by pulling it straight out 5 Remove 2 screws holding fan motor to orifice 4 5 Door assembly 1 Support the door...

Страница 12: ... Then lower your finger to seat the door onto the hinge NOTE Door alignment is crucial If door is misaligned apply pressure until alignment is achieved NOTE Adjust so that the upper portion of the door will touch firmly to the oven cavity front plate without pushing the door If the door assembly is not mounted properly microwave power may leak from the clearance between the door and oven 9 Tighten...

Страница 13: ...motor 3 Remove the turntable motor by removing screw NOTE After reinstalling the new turntable motor and reconnecting the 2 lead wires reinstall the motor cover by rotating it around 180 tucking the 2 tabs under the base in the 2 provided slots then screw the single tab to the base using a 4mm 6mm screw 4 7 Quartz heater 1 Disconnect lead wires from both side of heater terminals 2 Remove 2 screws ...

Страница 14: ...connect 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 14 NN GD462M NN GD452W NN GT462M ...

Страница 15: ...arge high voltage charge 2 Remove the H V lead wire from magnetron terminals 3 Disconnect 2 connectors from CN701 CN702 on H V Inverter U 4 Remove 1 screw holding grounding plate to the base 5 Press 1 encircled locking tab and then slide 4 locking tabs of Inverter bracket at the bottom of the base in direction of arrows 6 Remove 1 screw holding H V Inverter to Inverter bracket 7 Remove 1 screw hol...

Страница 16: ...Short Switch 1 Unplug lead wires from Inverter Power Supply U primary terminals 2 Connect test probes of ohm meter to the disconnected leads that were connected to Inverter Power Supply U 3 Test the continuity of short switch with door opened and closed positions using lowest scale of the ohm meter Normal continuity readings should be as follows Door Opened Door Closed 0Ω Close Ω Open 5 3 Magnetro...

Страница 17: ...or GT462M models a Press Timer pad twice b Press Start pad once c Press Micro Power pad once 5 Program oven at High power for 1 minute and press Start pad a After approximately 3 seconds oven stops operating b During oven operation the input current is approximately 0 4A INPUT CURRENT FAILURE CODE Unplug CN701 0 4A Oven stops in 3 seconds after started If both a and b check OK the Inverter Power S...

Страница 18: ...again by following the component test procedures 6 2 Measurement of microwave output The output power of the magnetron can be determined by performing IEC standard test procedures However due to the complexity of IEC test procedures it is recommended to test the magnetron using the simple method outlined below Necessary Equipment 1 liter beaker Glass thermometer Wrist watch or stopwatch NOTE Check...

Страница 19: ... 7 230V AC is present on the digital programmer circuit Terminals of power relay s and primary circuit of Digital Programmer Circuit When troubleshooting be cautious of possible electrical shock hazard Before troubleshooting operate the microwave oven following the correct operating procedures in the instruction manual in order to find the exact cause of any trouble since operator error may be mis...

Страница 20: ...n or loose connection of high voltage circuit especially magnetron filament circuit NOTE Large contact resistance will cause lower magnetron filament voltage and cause magnetron to have lower output and or be intermittent 3 Defective high voltage component H V Inverter Power Supply U Magnetron Check high voltage component according to component test procedure and replace if it is defective 4 Open ...

Страница 21: ...odel press Clock button once press Timer button once press Start button once press Micro Power button once For GT462M model press Timer pad twice press Start pad once press Micro Power pad once Program unit for operation H95 H97 H98 H99 appears in display window a short time after Start pad is pressed and there is no microwave oscillation Alternate way to troubleshoot oven with AC Ampere meter use...

Страница 22: ...edure Power will Ammeter reading is To do Remedy Shut off in 23 seconds after Start 1 Between 0 5A and 1 0A Check and repair open magnetron circuit Open magnetron wiring between Inverter and magnetron terminal 2 Between 1 0A and 2 0A Check continuity of D702 in Inverter PCB 1 D702 shorted Replace H V Inverter Z606YBA00QP 2 D702 is OK Replace magnetron Shut off in 3 seconds after Start 1 Less than ...

Страница 23: ...DC C702 ZCWF4305N851 FILM CAPACITOR 1 3µF 250VDC DB701 Z0FBBQ000006 RECTIFIER BRIDGE 1 L701 Z5020W100AP CHOKE COIL 1 R702 Z0CM562JA002 SAND BAR RESISTOR 1 T701 Z609ABA00GP TRANSFORMER 1 INCLUDING D701 D702 C706 C707 D701 D702 Z0FBAZ000003 DIODE 2 C706 Z0C3F562A002 FILM CAPACITOR 1 5600PF 3KV C707 Z0C3F822A002 FILM CAPACITOR 1 8200PF 3KV 23 NN GD462M NN GD452W NN GT462M ...

Страница 24: ...8 EXPLODED VIEW AND PARTS LIST 8 1 EXPLODED VIEW 24 NN GD462M NN GD452W NN GT462M ...

Страница 25: ... B 1 25 Z65439X70EP SENSOR COVER C 1 26 Z61425U30XN MICRO SWITCH 1 PRIMARY LATCH SWITCH 27 Z61415U30XN MICRO SWITCH 1 SECONDARY LATCH SWITCH 28 Z6145 1F90 THERMAL CUTOUT 1 29 Z612E9X70EP INCANDESCENT LAMP U 1 30 Z61785U30XN MICRO SWITCH 1 SHORT SWITCH 31 Z606YBA00QP H V INVERTER U 1 32 Z2M261 M39R MAGNETRON 1 33 Z62309V60AP FUSE 1 EPG GPG 15A 33 Z62309W40HP FUSE 1 WPG SPG 10A 35 Z66629Y00AP GROUND...

Страница 26: ...PG E5 Z83379X70HWP MEMBRANE SHEET 1 GD452W WPG E5 Z83379X70HSP MEMBRANE SHEET 1 GD452W SPG E6 Z82569Y00AP DOOR OPENING LEVER 1 E7 Z80375K00AP COOK BUTTON SPRING 1 E8 Z803G9M60SBP POP OUT DIAL U 1 GD462M E8 Z803G9M60HBP POP OUT DIAL U 1 GD452W E9 Z80189Y40AP DIAL SUPPORT 1 GD462M GD452W E10 Z82989Y40SAP BUTTON 1 GD462M E10 Z82989Y40HAP BUTTON 1 GD452W E11 Z82989Y90SAP BUTTON B 1 GD462M E11 Z82989Y9...

Страница 27: ...BASE 1 GT462M GPG E24 Z891P9Y60SBP DOOR OPENING BUTTON U 1 GT462M GPG E25 Z630Y9X80SGP MEMBRANE SWITCH U 1 GT462M GPG E26 Z82569Y00AP DOOR OPENING LEVER 1 E27 Z80375K00AP COOK BUTTON SPRING 1 E28 Z81279Y00AP BACK PANEL 1 GT462M GPG E29 Z66139Y20AP BACKSTOP 1 GT462M GPG E35 Z00079X80SGP NAME PLATE 1 GT462M GPG 27 NN GD462M NN GD452W NN GT462M ...

Страница 28: ...s Set Remarks D1 Z30189Y00AP DOOR KEY A 1 D2 Z302A9X70SEP DOOR A U 1 GD462M D2 Z302A9X70HEP DOOR A U 1 GD452W D2 Z302A9X80SGP DOOR A U 1 GT462M D3 F301P9X70EP DOOR E U 1 D4 Z30215G10XN DOOR KEY SPRING 1 D5 Z30859Y00AP DOOR C 1 28 NN GD462M NN GD452W NN GT462M ...

Страница 29: ... 5 WIRING MATERIALS Ref No Part No Part Name Description Pcs Set Remarks W1 Z030A9X70EP LEAD WIRE HARNESS 1 INCLUDING MAGNETRON THERMISTOR W2 Z030E9Y10QP H V LEAD WIRE 1 29 NN GD462M NN GD452W NN GT462M ...

Страница 30: ... GD452W WPG P2 Z01029X70HSP PACKING CASE PAPER 1 GD452W SPG P2 Z01029X80SGP PACKING CASE PAPER 1 GT462M GPG P3 Z01049Y00AP UPPER FILLER 1 P4 Z01059Y00AP LOWER FILLER 1 P5 Z01068100XN P E BAG 1 P6 Z01078J00XN DOOR SHEET 1 P7 Z01089X70EP RACK PACKING 1 GD462M GD452W P7 Z01089X90QP RACK PACKING 1 GT462M P8 Z06014N30BP COOKING TRAY 1 P9 Z01099Y00AP SHEET 1 GD462M GT462M P10 Z060V9X70EP OVEN RACK 1 P11...

Страница 31: ...9 DIGITAL PROGRAMMER CIRCUIT 9 1 SCHEMATIC DIAGRAM NN GD462M GD452W 31 NN GD462M NN GD452W NN GT462M ...

Страница 32: ...32 NN GD462M NN GD452W NN GT462M ...

Страница 33: ...9 2 SCHEMATIC DIAGRAM NN GT462M 33 NN GD462M NN GD452W NN GT462M ...

Страница 34: ...34 NN GD462M NN GD452W NN GT462M 02 12 S 9X7 S 9X8 Printed in China ...

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