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1. High voltage is present at the high voltage terminal of the voltage transformer during any cooking 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
capacitor (see page 13).
COMPONENT TEST PROCEDURE
1. High voltage transformer
(A) Remove connections from the transformer terminals
and check continuity.
(B) Normal readings should be as follows:
Secondary winding Approx. 150Ω ¡ 10%
Filament winding Approx. 0Ω
Primary winding Approx. 0Ω
2. High voltage capacitor
(A) Check continuity of capacitor with meter on the
highest OHM scale.
(B) A normal capacitor will show continuity for a short
time, and then indicate 9MΩ once the capacitor is
charged.
(C) A shorted capacitor will show continuous continuity.
(D) An open capacitor will show constant 9MΩ.
(E) Resistance between each terminal and chassis should
be infinite.
3. High voltage diode
(A) Isolate the diode from the circuit by disconnecting the
leads.
(B) 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. Meter with 6V, 9V or higher
voltage batteries should be used to check the front-
back resistance of the diode, otherwise an infinite
resistance may be read in both directions. A normal
didoes resistance will be infinite in one direction and
several hundred KΩ in the other direction.
4. Magnetron
For complete magnetron diagnosis, refer to “Measure-
ment of the Microwave Output Power”. (Page 8)
Continuity checks can only indicate and open filament
or a shorted magnetron.
To diagnose for an open filament or shorted magnetron,
(A) Isolate magnetron from the circuit by disconnecting
the leads.
(B) A continuity check across magnetron filament termi-
nals should indicate 0.1ohm or less.
(C) A continuity check between each filament terminal
and magnetron case should read open.
5. Fuse
If the fuse in the primary and monitor switch circuit is
blown when the door is opened, check the primary and
monitor switch before replacing the blown fuse. In case
the fuse is blown by an improper switch operation,
replace the defective switch and fuse at the same time.
Replace just the fuse if the switches operate normally.
CAUTION :
REPLACE BLOWN FUSE WITH 15
AMPERE FUSE.