Component Test Procedure; Primary, Secondary Latch Switch Interlocks & Power Relay Ry1; Short Switch; Magnetron - Panasonic NN-CF771S Service Manual

7 COMPONENT TEST PROCEDURE

1. High voltage is present at the output terminals of the High Voltage
Inverter (U) including aluminum heat sink during any cook cycle.
2. It is neither necessary nor advisable to attempt measurement of the
high voltage.
3. Before touching any oven components, or wiring, always unplug
the power cord and discharge the high voltage capacitors (see page
9).
7.1. Primary, Secondary Latch
Switch interlocks & Power
Relay RY1
1. Unplug lead connectors to Power Relay RY1 and verify
open circuit of the Power Relay RY1 1-2 terminals.
2. Unplug lead connectors to Primary Latch Switch and
Secondary Latch Switch.
3. Test the continuity of switches at door opened and closed
positions with ohm meter (low scale).
Normal continuity readings should be as follows.
Primary Latch Switch
Secondary Latch Switch
Power Relay RY1
7.2.

Short Switch

1. Unplug lead wires from Inverter Power Supply (U) primary
terminals.
2. Connect test probes of ohm meter to the disconnected
leads that were connected to Inverter Power Supply (U).
3. Test the continuity of short switch with door opened and
closed positions using lowest scale of the ohm meter.
Normal continuity readings should be as follows.
Door Opened
0Ω (Close)
WARNING
Door Closed Door Opened
Ω(Open)
0Ω (Close)
Ω(Open)
0Ω (Close)
Ω (Open) Ω(Open)
Door Closed
Ω (Open)
7.3.

Magnetron

Continuity checks can only indicate an open filament or a
shorted magnetron. To diagnose for an open filament or
shorted magnetron.
1. Isolate magnetron from the circuit by disconnecting the
leads.
2. A continuity check across magnetron filament terminals
should indicate one ohm or less.
3. A continuity check between each filament terminal and
magnetron case should read open.
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NN-CF771S