Panasonic NN-CT878SBPQ User manual

HAD0712001C2
Microwave Oven
NN-CT878SBPQ
32L
United Kingdom
Chaos
Defrost
Vegetables
Potatoes
Fish
Pizza
Chicken
Meat
Crispy Top
Bake
10
min
1
min
10
sec
1
h
Micro Power Grill 1-2-3
Convection
Combination
Turbo-Bake
Memory
Timer
Start
Stop / Cancel
less
more
NN-CT878S
Power source 240V AC Single Phase 50Hz
Power requirements Microwave 1220W
Grill 1560W
Convection 1350W
Combi 2870W
Output (IEC60705) Microwave 1000W
Grill 1500W
Convection 1250W
Microwave frequency 2450Mhz
Timer 99 min 99 second
Oven cavity size 32L
Outside dimensions 530mm(W) x 508mm(D) X 344MM (H)
Inside dimensions 350mm(W) X 360mm(D) x 250mm(H)
Weight 21Kg
© 2007 Matsushita Electric Industrial Co., Ltd. All rights reserved.
Unauthorized copying and distribution is a violation of law.

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1 Contents
1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 Inverter Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3 Feature Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
4 Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
5 Operation And Digital Programmer Circuit Test Procedure . . . . . . . . . . . . . . . . . . . 5
6 Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7 Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
8 Description of the Operation Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
9 Cautions to be Observed when Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
10 Part Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
11 Component Test Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
12 Measurements and Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
13 Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
14 Description of Operating instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
15 Exploded View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
16 Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
17 Door Assy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
18 Escutcheon Base. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
19 Packing and Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
20 Trim Kit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
21 Digital Programmer Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
22 Key Board Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

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2 Inverter Warning
The inverter board looks like a regular PCB, however, this PCB
drives the magnetron tube using very high voltages and cur-
rent.
It has
1. Very high voltage and high current
2. An Aluminium heat sink that becomes very hot
3. The capacitors on the inverter circuit will contain a high
voltage charge even when the oven is not operating.
Do not
1. Do not touch the circuitry as it contains very high volt-
ages. When replacing the board please take extreme
care to avoid possible electric shock. High voltages may
remain in the circuit.
2. Do not touch the aluminium heat sink as it will become
very hot. It also contains high voltages.
3. Do not attempt to repair the inverter 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 are loose. It is very dangerous to operate the
inverter circuit board without a proper ground connection.
Inverter Grounding
Figure 1
Inverter PCB layout
Figure 2
3 Feature Chart
Function BPQ
Microwave 6
Grill 3
Convection 17
Combi Yes
Sensor Reheat -
Sensor Cook 5
Sensor Combi 11
Auto Preheat Combi -
Weight Defrost 3
Weight Combi 2
Weight Reheat -
Weight Cook -
Memory Cook 3
Weight Crisp -
Stage Cooking 3 stage
Delay / Stand Yes
More / Less Yes
Kg -> lb/oz Yes
Clock 12h
Word Prompt English
Step by Step LED

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4 Control Panel

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5 Operation And Digital Programmer Circuit Test Procedure

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6 Schematic Diagram

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7 Wiring Diagram
Wiring Harness

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8 Description of Operating instruction
8.1. 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. The level of output power is controlled by the
drive signal level from the inverter circuit.
NOTE1: The ON/OFF time ratio does not correspond with
the percentage of microwave power since approximately 2
seconds are required for heating the magnetron filament.
NOTE: 2 If microwave cooking is over 8 minutes on HIGH
power, the fan motor rotates for 1 minute after cooking to
cool the oven and electrical components.
Duty cycles for microwave cooking
8.2. Grill Cooking
The digital programmer circuit controls the grill power by oper-
ating the power relay RY4 in the sequence shown in the table
below
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 display window has
elapsed, the oven turns off automatically via the control
signal from the digital programmer circuit.
Note: After auto cooking if the oven temperature is
over the predetermined temperature the fan motor
rotates to cool the oven and its components.
Defrost Menu’s
Weight Menu’s
Output Duty ON/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”
Duty ON/OFF
ON Time OFF Time
Grill 1 66” 0”
Grill 2 54” 12”
Grill 3 42” 24”
Category 1st Touch Weight Cooking Time
Turbo Defrost 500g 8m 20s
Category 1st Touch Weight Cooking Time
1. Whole Chicken 1000g 23m 54s
2. Chicken Pieces 500g 14m 40s
3. Beef 900g 26m 59s
4. Lamb 1200g 30m 06s
5 Pork 1200g 35 m 00s