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NN-C897WB
NN-C897CB
NN-C877WB
NN-C877CB
COMPONENT TEST PROCEDURE
High voltage is present at the high voltage terminal of the high
voltage transformer during operation. It is neither necessary or
advisable to attempt measurement of this high voltage. Before
FILAMENT WINDING
0 ohm
touching any oven components or wiring, always unplug the
TRAN
=
oven from its power source and discharge the high voltage
©
capacitor.
RX1 SCALE
$
SECONDARY WINDING
TERMINALS
1. High voltage transformer
(A) Remove the connections from the transformer terminals and check
the cold winding resistance.
80 -120 ohm
Secondary winding
Approx 80-120 ohm
Filament winding
Approx 0 ohm
Primary winding
Approx 0-3 ohm
PRIMARY WINDING
TERMINALS
INFINITY
HIGHEST
OHM
2. High voltage capacitor
sate
(A) Check the continuity of the capacitor with the meter on the highest
ohm scale.
(B) A normal capacitor will show continuity for a short time and then
indicate 9 M ohm once the capacitor is charged.
(C) A shorted capacitor will show continuous continuity.
(D) An open capacitor will show a constant 9 M ohm
(E) Resistance between each terminal and the case should read infinity.
HIGH VOLTAGE
_PAPACITOR
=e"
HIGHEST
OHM
SCALE
ANIENNA CASKEI
ANTENNA
3. Magnetron
(A) Continuity checks on the magnetron can only indicate an open
filament or shorted magnetron.
RXT SCALE
(B) Disconnect leads to the magnetron.
0-1 ohm
(C) A continuity check between each filament should read one ohm or
less.
COOLING
(D) A continuity check between each filament and the magnetron case
should read infinity.
MAGNETRON
CASE
TERMINALS
INFINITY
HIGHEST
OHM
SCALE
-20-
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