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:-9970, NE-9970C
+9870, NE-9870C
CAUTION
Do not touch any parts of the circuitry on the digital
programmer
circuit since static electric discharge
may damage this control panel.
Always ground yourself while working on this panel to
discharge any static charge built up in your body.
1) Place a water load in the oven.
2) Unsolder 2 shielded wires connected to sensor terminals.
3) Tap Auto Sensor Cook Control Pad once to set Auto Sensor cook-
ing at A1 and tap Start Pad
4) About 10 seconds after Start Pad is tapped, short shielded wires for
5 seconds and then remove them. Before shorting the shielded
wires you can watch the sensor heater glow red.
5) The oven lamp will dim a little, about 50 seconds after the Start Pad
is tapped. This indicates that magnetron has started oscillation.
6) 20 seconds after magnetron oscillation, short the shielded wires
again. The oven should turn off automatically when the shielded
wires are shorted.
7. Low voltage transformer
Check the voltage of secondary winding of the low voltage transfor-
mer (L.V.T.). The normal voltages of the L.V.T. with no load should read
as shown in Fig. 37-A and 37-B.
When measuring the voltage of L.V.T., measure the voltage between
-each pin of the L.V.T. with the connector (CN2) unplugged.
CAUTION
A 120V AC is present at the primary circuit of the low
voltage transformer. When
checking the secondary
voltage of low voltage transformer, be cautious of
possible shock hazard.
8. To test the oven temp sensor thermistor
This sensor monitors the heat produced by the heater circuit and
maintains. the oven temperature the user had selected normal room
temperature, especially in a kitchen can vary anywhere from 50°F to
90°F. The reading across the oven sensor thermistor should be within
360K ohm to 800K ohm when read in an area within 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 5-pin connector
(CN6) from the DPC otherwise a false reading may be Indi-
cated.
:
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 50°F to 90°F range.
SENSOR
HEATER
TERMINALS
SHIELDED
WIRE
SENSOR
TERMINALS
Fig. 36
For NE-9970, NE-9970C
'
Primary voltage::-::-AC 120V
Fig. 37-A
For NE-9870, NE-9870C
PIN NO. OF LV.T
SECONDARY VOLTAGE
Primary voltage:---:-AC 120V
Fig. 37-B
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