Component Test Procedure - Panasonic NE-C1153 Service Manual

10 COMPONENT TEST PROCEDURE

CAUTION
1. High voltage is present at the high voltage terminal of the high
voltage transformer during any cook cycle.
2. It is neither necessary nor advisable to attempt measurement of
the high voltage.
3. Before touching any oven components, or wiring, always unplug
the oven from its power source and discharge the high voltage
capacitor.
10.1. High voltage transformer
1. Remove connections from the transformer terminals and
check continuity.
2. Normal (cold) resistance readings should be as follows:
Secondary winding - Approx. 80Ω ~ 120Ω
Filament winding - Approx. 0Ω
Primary winding (0V - 208V). Approx. 0Ω ~ 3Ω
10.2. High voltage capacitor
1. Check continuity of capacitor with ohmmeter on highest
OHM scale.
2. A normal capacitor will show continuity for a short time, and
then indicate 9MΩ once the capacitor is charged.
3. A shorted capacitor will show continuous continuity.
4. An open capacitor will show constant 9MΩ.
(Due to internal 9MΩ resistor)
5. Resistance between each terminal and chassis should be
infinite.
10.3. Diode
1. Isolate the diode assembly from the circuit by disconnecting
the leads.
2. With the ohmmeter set on the highest resistance scale,
measure the resistance across the diode terminals.
Reverse the meter leads and again observe the resistance
reading. A meter with 6V, 9V or higher voltage batteries
should be used to check the front-to-back resistance of the
diode, otherwise infinite resistance may be read in both
directions.
A normal diode's resistance will be infinite in one direction
and several hundred KΩ in the other direction.
10.4. Magnetron
Continuity checks can only indicate an open filament or a
9.5. Replacement of the cavity light
bulb
CAUTION unplug the unit from electricity supply before
replacing the Oven Lamp.
If the Oven Lamp burns out, you can replace it yourself by
following these simple directions.
1. Unscrew the Oven Lamp Cover which is located on the left
side of the cabinet.
2. Replace the old lamp with a new 220/240V, 25W max., E-
14 lamp.
3. Close the Oven Lamp Cover with screw.
Caution: Do not clean this appliance with a water jet.
shorted magnetron. To diagnose for an open filament or
shorted magnetron.
1. Isolate magnetron from the circuit by disconnecting the
leads.
2. A continuity check across magnetron filament terminals
should indicate one ohm or less.
3. A continuity check between each filament terminal and
magnetron case should read open.
10.5. Membrane key board
(Membrane switch assembly)
Check continuity between switch terminals, by pressing an
appropriate pad on the key board.
The contacts assignment of the respective pads on the key
board is as shown in the schematic diagram of DPC.
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NE-C1153 / NE-C1153C