32 OVEN SYSTEMS
Magnetrons
Figure 30. Magnetrons supply the RF energy at
2.45GHz and begin to oscillate when they are supplied with approximately 4.1 kVDC at approximately .350 mA. During operation each magnetron will output a nominal 1 kW of power.
If replacement is required, conduct a microwave leakage test (page 27) after installation of new magnetron.
FA 
F
FILAMENT AND
HIGH VOLTAGE
TERMINALS
4.A continuity check between either filament terminal and the magnetron chassis should indicate an infinite resistance (open).
CAUTION: Be careful to not allow debris into the wave guides when servicing the magnetrons.
Stirrer Motor and Assembly
The stirrer is responsible for evenly distributing hot air and microwaves that are launched from the top of the oven into the cook cavity. The stirrer is driven by a 3.6 RPM motor, which remains on during a cook cycle or when the oven is in TEST
MODE.
The stirrer motor can be tested in TEST MODE (see page 15).
CAUTION: Be careful to not allow debris into the waveguides when servicing the stirrer assembly.
ANTENNA
Figure 30: Magnetron
Testing a Magnetron for an Open/Shorted Filament
DANGER: The only safe way to test a magnetron is by a resistance test of its
filament. Never attempt to measure the magnetron using any other method while the microwave system is on. Death or serious injury could occur.
1.Disconnect the AC power source and discharge the
2.Isolate the magnetron from the circuit by removing the wires from the F and FA terminals. Figure 30.
3.An ohmmeter connected between the filament terminals (F, FA) should indicate a reading of less than 1 ohm. Figure 30.
Wave Guides
The wave guides channel microwave into the cook cavity. If debris or contamination gets into the wave guides, the life of the magnetrons may be shortened. Be careful to not allow debris into the waveguides when servicing the magnetrons or stirrer assembly.
Troubleshooting
The following faults may occur in relation to the microwave system:
-F3: Magnetron Current Low (see page 41)
-F5: Magnetron Over Temperature (see page 42)
The following issues may occur in relation to the microwave system:
-Electrical component failure (blank or scrambled display, damaged control board, etc.)
-Food not cooking properly