Panasonic NN-S262SF APH User manual

ORDER NO.SIMMC 0203005C1
E2
Microwave Oven
NN-S262SF / NN-S262BF / NN-S262WF / NN-S252BF / NN-
S252WF
APH(USA)
CPH(CANADA)
SPECIFICATIONS
2002 Shanghai Matsushita Microwave Oven Co., Ltd. / All rights
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Microwave Oven 1
1. FEATURE CHART 5
2. CONTROL PANEL (APH) 6
3. CONTROL PANEL (CPH) 7
4. OPERATION AND DIGITAL PROGRAMMER CIRCUIT TEST PROCEDURE 8
4.1. To set clock 8
4.2. Time cooking for two stage 9
4.3. Inverter turbo defrost 10
4.4. Inverter auto cooking 10
4.5. Popcorn 11
4.6. Auto reheat 11
4.7. Power level 12
5. SCHEMATIC DIAGRAM (APH) 12
6. SCHEMATIC DIAGRAM (CPH) 13
7. DESCRIPTION OF OPERATING SEQUENCE 14
7.1. Variable power cooking control 14
Variable Power Cooking 14
7.2. Inverter power supply circuit [NEW H.V.] 15
7.3. Inverter turbo defrost 15
Inverter Turbo Defrost 16
8. CAUTIONS TO BE OBSERVED WHEN TROUBLESHOOTING 16
8.1. Check the grounding 16
8.2. Inverter warnings [NEW H.V.] 16
8.3. When parts must be replaced, remove the power plug from the outlet. 18
8.4. When the 18 Amp fuse is blown due to the operation of short switch: 18
8.5. Avoid inserting nails, wire, etc. through any holes in the unit during operation. 18
8.6. Confirm after repair 19
9. DISASSEMBLY AND PARTS REPLACEMENT PROCEDURE 20
9.1. Magnetron 20
9.2. Digital programmer circuit (DPC) and membrane key board. 20
9.3. Low voltage transformer and/or power relays (RY1, RY2) 21
9.4. Inverter power supply (U) 22
9.5. Door assembly 24
9.6. Stirrer motor 25
9.7. Blower motor (U) 25
9.8. Fan motor A (for H.V. inverter (U) cooling) 25
9.9. Fan motor B (for magnetron cooling) 26
9.10. Turntable motor 26
10. COMPONENT TEST PROCEDURE 27
10.1. Primary latch switch, secondary (secondary latch switch and power relay B) interlocks. 27
10.2. Short switch & monitor 27
10.3. Magnetron 28
10.4. Membrane key board (Membrane switch assembly) 28
10.5. Inverter power supply (U) 28
11. MEASUREMENTS AND ADJUSTMENTS 30
11.1. Adjustment of primary latch switch, secondary latch switch and short switch. 30
11.2. Measurement of microwave output 31
TABLE (1L-1min.test) 31
12. PROCEDURE FOR MEASURING MICROWAVE ENERGY LEAKAGE 32
12.1. Equipment 32
12.2. Procedure for measuring radiation leakage 32
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12.2.1. Measurement with the outer panel removed. 33
12.2.2. Measurements with a fully assembled oven. 33
12.3. Record keeping and notification after measurement 33
12.4. At least once a year, have the radiation monitor checked for calibration by its manufacturer. 33
13. TROUBLESHOOTING GUIDE 34
13.1. Trouble related to digital programmer circuit 36
13.2. Troubleshooting of inverter circuit (U) and magnetron [NEW H.V.] 38
13.3. How to check the semiconductors using an OHM meter 38
14. EXPLODED VIEW AND PARTS LIST 39
15. PARTS LIST 39
16. DOOR ASSEMBLY 43
17. WIRING MATERIALS 43
18. ESCUTCHEON BASE ASSEMBLY 44
19. PACKING AND ACCESORIES 45
20. DIGITAL PROGRAMMER CIRCUIT 46
21. DIGITAL PROGRAMMER CIRCUIT 48
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reserved. Unauthorized copying and distribution is a violation of law.
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1. FEATURE CHART
MODEL NN-S262 NN-S252
FEATURE
Five Stage Cooking O O
Inverter Turbo Defrost O O
Sensor Reheat O -
Sensor Cooking O -
Auto Reheat - O
Inverter Auto Cooking - O
Quick Min O O
Popcorn O O
Digital Clock O O
Timer O O
Child Safety Lock O O
Vent Fan O O
Cooktop Light O O
2. CONTROL PANEL (APH)
6

3. CONTROL PANEL (CPH)
7

4. OPERATION AND DIGITAL PROGRAMMER CIRCUIT
TEST PROCEDURE
4.1. To set clock
8

OPERATION SCROLL DISPLAY
1. Plug the power supply
cord into wall outlet.
BEFORE USE REFER TO
OPERATING
INSTRUCTIONS
2. Press [Clock] pad.
3. Enter time of day
(TOD) by pressing
appropriate [Number]
pads.
4. Press [Clock] pad.
TOD has now been
resistered into the
digital programmer
circuit and will count up
by minutes.
4.2. Time cooking for two stage
OPERATION SCROLL DISPLAY
1. Place a water load in
the oven.
2. Press [Power Level]
pad once to set High
power.
(1st stage)
3. Set for 5 seconds by
pressing [ Number ]
pads.
5 sec.= [5]
4. Press [Power Level]
pad 6 times to set
Medium power.
(2nd stage)
5. Set for 1 minute by
pressing [Number ]
pads.
1 Min.= [1] [0] [0]
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OPERATION SCROLL DISPLAY
6. Press [Start] pad.
7. When 1st stage
cooking time has
elapsed. Oven beeps
twice and automatically
switches to 2nd stage
cooking.
8. When 2nd stage
cooking time has
elapsed, oven beeps 5
times and shuts off.
Time of day or colon if
set appears in the display
4.3. Inverter turbo defrost
OPERATION SCROLL DISPLAY
1. Press [Inverter Turbo
Defrost] Pad.
INVERTER TURBO
DEFROST
SET WEIGHT
2. Set the weight for 1 lb
by pressing [Number]
pads.
1 Ib= [1] [0]
3. Press [Start] pad.
4. Press [Stop/Reset]
Pad twice.Oven shuts
off.
Time of day or colon if
set appears in the
display.
4.4. Inverter auto cooking
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OPERATION SCROLL DISPLAY
1. Press [Beverages]
pad once.
BEVERAGES
PRESS SERVING
WEIGHT
2. Press [Serving/Weight
] pad twice to select 2
cups
2 CUPS
3. Press [Start] pad.
When cooking time has
elapsed, Oven beeps 5
times and shuts off.
Time of day or colon if
set appears in the
display.
4.5. Popcorn
OPERATION SCROLL DISPLAY
1. Press [Popcorn] pad
once for 3.5 oz serving.
(Select 3.5, 3.0, 2.85,
2.65, 1.75 oz)
2. Press [Start] pad.
When cooking time has
elapsed, Oven beeps 5
times and shuts off.
Time of day or colon if
set appears in the
display.
4.6. Auto reheat
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OPERATION SCROLL DISPLAY
1. Press [Auto Reheat]
pad twice for two
servings.
2. Press [Start]
pad.Auto Reheat cycle
begins time counts
down.
3.When cooking time
has elapsed, Oven
beeps 5 times and shuts
off.
Time of day or colon if
set appears in the
display.
4.7. Power level
Press Power
Level
Power Level Display Window
once P10 (HIGH) P10
twice P9 P9
3 times P8 P8
4 times P7 (MED.HIGH) P7
5 times P6 (MEDIUM) P6
6 times P5 P5
7 times P4 P4
8 times P3 (MEDIUM-
LOW)
P3
9 times P2 P2
10 times P1 (LOW) P1
5. SCHEMATIC DIAGRAM (APH)
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6. SCHEMATIC DIAGRAM (CPH)
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7. DESCRIPTION OF OPERATING SEQUENCE
7.1. Variable power cooking control
High Voltage Inverter Power supply (U) controls output power by the signal from Digital Programmer
Circuit (DPC). Power relay stays ON for P4 to P10 and For P1 to P3, both inverter drive signal and
power relay to control output power.
NOTE:
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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
OUTPUT ON-OFF TIME OF
POWERSETTING POWER(
%)
POWER RELAY B
(RY1)
APPROX. ON(SEC) OFF(SEC)
HIGH
P10
100% 22 0
P9 90% 22 0
P8 80% 22 0
MEDIUM-
HIGH
P7 70% 22 0
MEDIUM P6 60% 22 0
P5 50% 22 0
P4 40% 22 0
MEDIUM-
LOW
P3 30% 17 5
P2 20% 11 11
P1 10% 6 16
DEFROST P3 30% 17 5
7.2. Inverter power supply circuit [NEW H.V.]
This Inverter Power Supply Circuit supplies 4,000V DC to the magnetron tube from the line voltage,
120V 60Hz AC input. functions as the H.V. transformer, the H.V.capacitor and H.V.Diode.
1. The AC input voLtage 120V 60Hz is rectified to DC voltage immediately.
2. DC voltage will be supplied to the switching devices called IGBT.
These devices will be 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 up to 2,000V AC
and approximately 3V AC by means of transformer.
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 ciruit.
6. Then this signal will be fed back to the microcomputer in the DPC to
determine operating conditions and output necessary to control PWM
signal to the Inverter Power Supply to control output power.
7.3. Inverter turbo defrost
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When this 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. Table shows the corresponding cooking times for
respective serving by categories.
2. When cooking time the display window has elapsed, the oven tums off
automatically by a control signal from the digital programmer circuit.
Inverter Turbo Defrost
WEIGHT SELECTED COOKING TIME
1.0LB 5 min.28 sec.
8. CAUTIONS TO BE OBSERVED WHEN
TROUBLESHOOTING
Unlike many other appliances, the microwave oven is high-voltage, high-current equipment. Though it
is free from danger in ordinary use, extreme care should be taken during repair.
CAUTION
Servicemen should remove their watches
whenever working close to or replacing the
magnetron.
8.1. Check the grounding
Do not operate on a 2-wire extension cord. The microwave oven is designed to be used when
grounded. When it is inoperative, make sure it is grounded properly before beginning repair work.
8.2. Inverter warnings [NEW H.V.]
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DANGER OF HIGH VOLTAGE AND HIGH /
TEMPERATURE (HOT/LIVE) OF THE INVERTER /
POWER SUPPLY (U)
This High Voltage Inverter Power Supply circuit
supplies very high voltage and very high current
for the magnetron tube. Though it is free from
danger 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 so danger exists because of
its high current and high voltages.
The aluminum heat sink is also energized with
high voltage (HOT), so do not touch when AC
input terminal is connected to the power line
because one of the IGBT switching power devices
(Collector) is directly connected to the Aluminum
heat sink.
The Aluminum heat sink may be HOT from heat
energy; therefore, extreme care should be taken
during servicing and replacing.
WARNING OF INVERTER POWER SUPPLY (U) /
GROUNDING
Check the High Voltage Inverter Power Supply
circuit grounding. This High Voltage Inverter
Power Supply circuit board must have a proper
chassis ground by the grounding bracket to the
chassis ground; otherwise, this H.V. Inverter
circuit board will expose very high voltage and
cause extreme DANGER! Be sure to have proper
grounding by the grounding plate and screws.
WARNING OF DISCHARGING HIGH VOLTAGE
CAPACITORS
Warning about the electric charge in 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. Please make sure
to touch chassis ground side first then short to the
output terminals.
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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 oven energized.
DO NOT measure the voltage in the high voltage
circuit including filament voltage of 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.
8.4. When the 18 Amp fuse is blown due to the operation of short switch:
WARNING
When the 18 Amp. fuse if blown due to the
operation of short switch, you must replace
Primary latch switch and short switch. Also
replace power relay B (RY1) when the continuity
check reads shorted contacts (1-2).
1. This is mandatory. Refer to "Measurements and Adjustments" for
these switches.
2. When replacing the fuse, confirm that it has the appropriate rating for
these models.
3. When replacing faulty switches, be sure mounting tabs are not bent,
broken or otherwise deficient in their ability to hold the switches.
8.5. Avoid inserting nails, wire, etc. through any holes in the unit during
operation.
WARNING
Never insert a wire, nail or any other metal object
through the lamp holes on the cavity or any other
holes or gaps, because such objects may work as
an antenna and cause microwave leakage.
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