Panasonic NE-3280 Service Manual page 29

of the diode, otherwise an infinite resistance may be read in both
directions. A normal diode's resistance will be infinite in one direction
and several hundred k in the other direction.
15.5. Membrane key board (Membrane switch assembly)
Check continuity between switch terminals, by tapping an appropriate pad on the key board. The
contacts assignment of the respective pads on the key board is as shown in digital programmer circuit.
15.6. Protector diode
1. Isolate the protector diode assembly from the circuit by disconnecting
its leads.
2. With the ohmmeter set on the highest resistance scale, measure the
resistance across the protector diode terminals. Reverse the meter
leads and again observe the resistance reading. A normal protector
diode's resistance will be infinite in both directions. It is faulty if it
shows continuity in one or both directions.
15.7. Temp sensor (Thermal protector)
A temp sensor is mounted on exhaust guide. Its purpose is to automatically shut off the oven in case
the cavity overheats for any reason.
The thermal protector will operate at 257°F(125°C).
The device is connected to the DPC on touch control modes.
When the thermal protector exceeds its temperature it will turn off the power to oven cavity and display
will go to reset mode.
The cooking program can be rest after cool-down.
THERMISTOR RESISTANCE VALUE
30K-120K at 10°C-30°C (50°F — 86°F)
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