Microwave Board, Stirrer Motor, Microwave Transformer Cooling Fan & Air Switch - Thermador CM301B Service Manual

Lit. No. 94-30-006B CM Oven Service Manual
MICROWAVE BOARD
The Microwave Board has one snap relay (K1).; Two Pin Headers (P1 and P3) and two
1/4" terminals (P2-1 and P2-2).
K1 Relay:
This relay transfers 120 Volts AC to the high voltage transformer to activate the micro-
wave circuit. The K1 Relay Coil is activated by 24 Volts DC from the relay board.
P1 Pin Header
This is a 3-pin header that receives 24 Volt DC from the Relay Board using a wire har-
ness from PIN Header P6 on the relay board.
P3 Pin Header
Pins 1 and 2 inputs 12 Volts AC from the halogen light transformer circuit. Pins 3 and 4
output 12 volts DC (Rectified through a series of diodes) to activate the upper oven (or
single oven) latch motor.
P2-1 Terminal:
This terminal inputs 120 Volts AC from the latch interlock switches.
P2-2 Terminal:
This terminal outputs 120 Volts AC to the transformer when relay K1 closes.
STIRRER MOTOR
The stirrer motor is a 120 volt AC motor. The purpose of the stirrer motor is to run the
stirrer blades at the output of the wave guide. The stirrer rotates at about 60 rpm.
As the microwave energy enters the oven cavity through the wave guide, it bounces off
the rotating stirrer blades and is reflected throughout the oven cavity at constantly
changing angles, providing a more even microwave distribution.
In the jet impinged oven, the stirrer blade also mixes the air flow into the top of the
oven.
COM
NC
NO
NO
COM
NC
Air Switch
Microwave Transformer Cooling Fan and Air Switch
The Microwave Transformer Cooling Fan is a box fan mounted between the control
panel and the high voltage transformer. There is an air switch (see illustration, above)
with a paddle mounted on the fan bracket. The fan blows air across the high voltage
transformer to keep the transformer cool. The air flow from the fan moves the paddle
on the air switch. The paddle movement closes the normally open contacts on the air
switch. The air switch is in series with the air switch located on the base area below the
lower oven. If this air switch does not close, you will see an F34 error code in the control
panel.
Page 67