NN-C781JF - Panasonic Home Appliance Service Manual (repair manual). Page 19

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In order to determine if the steam sensor function of the digital
programmer circuit is in working order or not, do the following
test.

1)  Place a water load (150 cc) in the oven.
2)  Tap Sensor Reheat pad.
3)  Tap Start Pad.
4)  Steam Sensor detects steam about 1.5 to 4 minutes after the

Start Pad is tapped.

5)  T1 time cooking automatically switches to remaining time cooking

(T2).

6)  The remaining cooking time (T2) appears in display window. If

the following cooking time appears, Steam Sensor function is
normal.

This sensor monitors the heat produced by the heater circuit and
maintains the oven temperature the user had selected. Normal
room 10˚C to 30˚C. The reading across the oven sensor
thermistor should be within 100K ohm to 300K ohm when
reading in an area with the 50˚F to 90˚F room temperature range.
If the resistance reading is out of the range stated here, the
sensor is detective and must be replaced.
NOTE 1: When measuring resistance disconnect the 3-pin
connector (CN6) from the DPC otherwise a false reading may be
indicated.
NOTE 2: If checking an oven sensor thermistor just after the
microwave oven has been operating, the sensor of course won’t
be room temperature. In this case the sensor must be removed
and allowed to cool down to the 10˚C to 30˚C range.

T2 TIME

18 Sec.~48 Sec.

T1 TIME

1 Min. 30 Sec.~4 Min.

(Remaining cooking time)