Diode, High Voltage Transformer, Magnetron Tube - Thermador CM301B Service Manual

CM Oven Service Manual Lit. No. 94-30-006B
DIODE
The diode is a device used to convert alternating current (AC) into pulsating direct
current (DC) allowing it to pass forward in one direction while blocking the current
flow in the opposite direction. There is no charge stored in this part.
HIGH VOLTAGE TRANSFORMER
The high voltage transformer has one primary winding and two secondary windings.
The "stepup" secondary winding converts 120 volts AC. To 2300 volts across the
transformer terminals.
The other secondary winding "steps down" 120 volts AC to 3.3 volts AC. Which heats
the magnetron tubes cathode filament. The cathode filament preheats approximately 1
second before the high voltage circuit is energized.
MAGNETRON TUBE
The magnetron tube is a vacuum tube in which the flow of electrons from the heated
cathode to the anode is controlled by a magnetic field to produce an electromagnetic
wave (2450 mhz). These electromagnetic waves are called "microwaves."
To operate the magnetron tube requires both a minimum power input of 3800 to 4000
volts DC. From the transformer. Diode, and capacitor, and 3.8 volts from the filament
transformer lead. The tube has a 650 watt rating.
Note
Wire mesh gasket (rf) between the magnetron tube and the wave guide must be in place
when reinstalling the tube. When reinstalling the tube, tighten the four tube nuts
diagonally. Do not tighten the two nuts on one side, then the two nuts on the other side.
(Removing and replacing the magnetron tube requires a microwave leakage test.)
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