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11. TEST AND CHECKOUT PROCEDURES,
AND TROUBLESHOOTING
CAUTIONS
DISCONNECT THE POWER SUPPLY CORD FROM
THE WALL OUTLET WHENEVER REMOVING THE
CABINET FROM THE UNIT. PROCEED WITH THE
TESTS ONLY AFTER DISCHARGING THE HIGH
VOLTAGE CAPACITOR AND REMOVING THE WIRE
LEADS FROM THE PRIMARY WINDING OF THE HIGH
VOLTAGE TRANSFORMER. (SEE FIGURE 30)
ALL OPERATIONAL CHECKS WITH MICROWAVE
ENERGY MUST BE DONE WITH A LOAD (1 LITER OF
WATER IN CONTAINER) IN THE OVEN.
A. TEST PROCEDURES
COMPONENTS
MAGNETRON
(Wire leads are removed)
HIGH VOLTAGE
TRANSFORMER
(Wire leads are removed)
NOTE: A MICROWAVE ENERGY LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS
SERVICED FOR ANY REASON.
TEST PROCEDURE
1) Measure the resistance:
Across the filament terminals of the
magnetron with an ohm-meter on Rx1
scale.
2) Measure the resistance:
Between each filament terminal of the
magnetron and the chassis ground
with an ohm-meter on highest scale.
1) Measure the resistance:
With an ohm-meter on Rx1 scale.
a. Primary winding;
b. Filament winding;
c. Secondary winding;
2) Measure the resistance;
With an ohm-meter on highest scale.
a. Primary winding to ground;
b. Filament winding to ground;
— 22 —
Filament
Winding
Primary
Winding
RESULTS
Normal reading:
Less than 1 ohm
Normal reading:
Infinite ohms
NOTE
Replace the magnetron, if the
magnetron checks and all of the
high voltage component tests are
good, but the unit still does not
heat a load.
Normal readings:
Approx. 0.44 ohms
Less than 0.1 ohm
Approx 105 ± 5 ohms
Normal readings:
Infinite ohms
Infinite ohms
Secondary
Winding
Figure 30
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