Panasonic NN-A750WB User manual

Order Number MOP00080014C2
Microwave Oven
NN-A750WB / NN-A720MB / NN-A770SB
27L
WHITE SILVERSTAINLESS
United Kingdom
SPECIFICATIONS
Specification
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Power Source 240VAC Singlephase, 50Hz
Power Requirements Micro1260WGrill 1360WConv1470w
Combi 2770W
Output (IEC705-88) Micro1000WGrill 1300WConv1400W
Microwave
Frequency 2450MHz
Timer 99 Minutes 99 Seconds
OvenCavitySize 27L
OutsideDimensions 510mm(W) x477mm(D) x314mm(H)
InsideDimensions 359mm(W) x352mm(D) x217mm(H)
Weight 15Kg
1995 Matsushita ElectricIndustrial Co., Ltd. All rights reserved.
Unauthorized copying and distribution isaviolation of law.
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1. Inverter Warning
The inverterboardlooks like a regularPCB, however, this PCB drives the magnetron tube using
veryhigh voltages and current.
It has
1. Veryhigh voltage and high current
2. AnAluminium heat sink that becomes veryhot
3. The capacitors on the inverter circuitwill containahigh voltage
charge even when the oven isnot operating.
Donot
1. Donot touch the circuitryas itcontains veryhigh voltages. When
replacing the board please take extreme care to avoidpossible
electricshock. High voltages mayremaininthe circuit.
2. Donot touch the aluminium heat sink as itwill become veryhot. It
also contains high voltages.
3. Donot attempt to repairthe inverter PCB as thiscan be very
dangerous. Replace the high voltage inverter circuitas acomplete
unit. Return the oldunitfullyrepacked inthe original shipping
box and completed paper work.
4. Donot adjust or tamper with the preset volume on the inverter
board. Itisverydangerous to adjust thispreset without proper
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test equipment.
5. Donot test the oven whilethe inverter grounding stripor screws
are loose. Itisverydangerous to operate the inverter circuitboard
with out aproper ground connection.
Figure 1
InverterPowerSupplyDiagram
Figure 2
InverterLayout
2. Feature Chart
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Function
Microwave 6
Grill 3
Convection 17
Combination YES
Weight Defrost 3
Weight Combination 8
Weight Reheat 4
Weight Cook 2
Stage Cooking 3 Stage
Delay/ Stand Yes
Kglb./oz. Yes
Clock 12 Hour
WordPrompt English
3. Control Panels
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4. Operation And Digital Programmer Circuit Test
Procedure
4.1. Setting The Clock
1. Plug the power supplycord into the wall outlet
2. Press the clock pad
3. Enter the time of the day
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4. Press the clock pad
4.2. Microwave Cooking
1. Place awater load inthe oven
2. Press Micro power once to set high power
3. Set time at 5sec. bypressing
1sec. pad 5times
4. Press Micro power pad 3times to set medium power
5. Set pad for 1minute bypressing 1min. pad once
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6. Press the start pad
7. When the first stage cooking has elapsed oven automatically
switches to second stage
8. When second stage cooking has elapsed oven bleeps 5times and
shuts off
4.3. Auto Weight Defrost
1. Select the desired program
2. Press gor lb. and oz.
3. Enter the weight bypressing the Up&DownPads.
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4. Press Start
4.4. DelayStand
1. Set power level and time
2. Press Stand
3. Set standing time
4. Press Start
4.5. DelayStart
1. Press delay
2. Set delaytime
3. Set power level and time
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4. Press start pad
4.6. Grill Operation
1. Select grill power press once for grill 1
2. Set cooking time
3. Press start
4.7. Convection Operation
1. Press convection pad to select oven temperature
2. Press start to preheat
3. Press time pads to enter cooking time
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4. Press start pad
4.8. Turbo Bake Operation
1. Press turbo bake pad to select oven temperature
2. Press grill pad to select grill power
3. Press start to preheat
4. Press time pads to enter cooking time
5. Press start
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4.9. Combination Cooking (Convection And Microwave)
1. Press combination pad
2. Press convection pad to select oven temperature
3. Select micro power
4. Press start ifpreheating
5. Set cooking time
6. Press start pad
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4.10. Combination Cooking (Grill And Microwave)
1. Press combination pad
2. Press grill pad to select oven temperature
3. Select micro power
4. Set cooking time
5. Press start pad
4.11. Combination Cooking (Turbo Bake And Microwave)
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1. Press combination pad
2. Press convection pad to select oven temperature
3. Select micro power
4. Press start ifpreheating
5. Set cooking time
6. Press start pad
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4.12. Auto Weight Cook Programs
1. Select the desired auto weight cook program
2. Press to select grams or pounds and ounces
3. Enter the weight bypressing the up and downpads
4. Press Start
5. Schematic Diagram
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6. Wiring Diagram
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7. Description of Operating instruction
7.1. Variablepower cooking control
The HIGH VOLTAGE INVERTER POWER SUPPLY controls the output powerbya signal fromthe
digital Programmercircuit DPC. The powerrelay(RY1) turns on tosupplypowertothe inverter
circuit. The level of output poweris controlledbythe drive signal level form the invertercircuit.
NOTE1: The ON/OFF time ratiodoes not correspond withthe percentage of microwave power
since approximately2 seconds are requiredforheating the magnetron filament. / NOTE: 2 If
microwave cooking is over8 minutes on HIGH power, the fanmotorrotates for1 minute after
cooking tocool the ovenand electrical components.
Dutycycles formicrowave cooking
Output DutyON/OFF
ON time OFF time
High 1000W 22” 0”
Defrost 440W 16” 6”
Medium 600W 22” 0”
Low 440W 22” 0”
Simmer 440W 15” 7”
Warm 440W 8” 14”
7.2. Grill Cooking
The digital programmercircuit controls the grill powerbyoperating the powerrelayRY4 inthe
sequence showninthe table below
Dutycycles forGrill Cooking
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DutyON/OFF
ON Time OFF Time
Grill 1 33” 0”
Grill 2 24” 9”
Grill 3 18” 15”
7.3. Auto weight defrost, Auto weight Cook
Whenanautocontrol feature is selectedand the start padpressed:
1. The digital programmer circuitdetermines the power level and the
cooking time and indicates the operating state inthe display. The
tableshowsthe corresponding cooking times for each category
and its respective weight.
2. When the cooking time inthe displaywindow has elapsed, the
oven turns off automaticallyviathe control signal from the digital
programmer circuit.
Note: After auto cooking ifthe oven temperature isover the
predetermined temperature the fan motor rotates to cool the oven
and its components.
AutoWeight Defrost
Category 1st Touch
Weight Cooking Time
Bread 100g 45s
Meat Items 200g 2m10s
Meat Joints 400g 6m20s
Autoweight Cook
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Category 1st Touch
Weight Cooking Time
1.Curry 300g 3m30s
2.Chinese Style 200g 2m10s
3.Pasta 250g 2m55s
4.Casserole 300g 3m15s
5.FreshFish 100g 1m30s
6.FreshVegetables 100g 2m20s
7.ChilledCrispyTop 300g 8m
8.FrozenCrispyTop 300g 12m
9.Jacket Potatoes 200g 9m
10.FrozenPotato
Products 200g 8m
11.Whole Chicken 1000g 19m20s
12.Lamb/Beef 500g 14m40s
13.ChilledPizza 200g 6m40s
14.FrozenPizza 200g 9m
7.4. Convection Cooking
1. The digital programmer circuitoperates the power relaysRY3,RY5
and RY6 inthe sequence as showninthe figure below.
2. When the oven reaches apredetermined temperature the digital
programmer circuitstops supplying power to relayRY5, resulting
inthe convection heater turning off.
3. When the temperature drops below the predetermined
temperature, the digital programmer circuitsupplies power to
power relayRY5 resulting inthe convection heater turning on.
Note: After the convection process, ifthe oven temperature is
higher than the predetermined temperature, the fan motor rotates
to cool the electroniccomponents and the oven.
Figure1
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