Short Switch & Monitor; Membrane Key Board (Membrane Switch Assembly); Inverter Power Supply (U) - Panasonic NN-V653WF Service Manual

6.2. Short switch & monitor
1. Unplug lead wires from Inverter Power Supply (U) primary
terminals.
2. Connect test probes of ohm meter to the disconnected leads
which 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.
6.3. 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.

6.4. Membrane key board (Membrane switch assembly)

Check continuity between switch terminals, by tapping an appropriate pad on the key board. The
contacts assignment of the respective pads on the key board is as shown in digital programmer
circuit.

6.5. Inverter power supply (U)

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