Testing The High Voltage Diode - TurboChef NGC (Tornado) Service Manual

28 THE MICROWAVE SYSTEM
        : High Voltage Diode (P/N 100481)
  : To hold the Cook Door open, for this
test, back out the top center screw around the
perimeter of the Cook Door. Continue backing
this screw out until the Primary and Secondary
Interlock Switches disengage. As this point, tighten
the screw until both Switches re-engage.
7. Using the same procedure, measure the leakage
around the oven's entire exterior surface. Record
the highest leakage.
HOW TO TEST MICROWAVE COMPONENTS
Testing the High Voltage Diode (P/N 100481)
The High Voltage Diode (Figure 21) is assembly
constructed by connecting several 1000 volt -1500
volt semiconductor diodes in a series in order to
increase the reverse voltage capability. In the circuit,
the High Voltage Diode conducts to prevent the
filament voltage from becoming positive, thus as
the High Voltage Winding of the transformer goes
to 2400 VPK, the High Voltage Capacitor is charged
to 2400 volts. When the High Voltage Winding
starts to go toward negative, the High Voltage Diode
FA
        : Magnetron (P/N 100861)
becomes non-conducting with the charged High
Voltage Capacitor in series with the High Voltage
Winding. When the transformer gets to its negative
peak of -2400 VPK, the voltage applied to the
Filament is negative 4500 volts.
      : Never attempt to measure high
voltage directly.
How to check a Diode
1. Disconnect the oven from the power source.
2. Isolate the Diode from the circuit.
3. Connect the meter leads to the Diode Terminals.
4. Infinite resistance (open) should be indicated in
the reverse direction.
5. Resistance readings in the forward direction may
be indeterminate.
6. If continuity in both directions: shorted Diode.
F
FILAMENT AND
HIGH VOLTAGE
TERMINALS
ANTENNA