WARNING
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
8).
5.1. 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.
Door Closed
Door Opened
Primary Latch Switch
0
Ω
(Close)
Ω
(Open)
Secondary Latch Switch
0
Ω
(Close)
Ω
(Open)
Power Relay RY1
Ω
(Open)
Ω
(Open)
5.2. Monitor Interlock 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 Monitor Interlock Switch with door
opened and closed positions using lowest scale of the ohm
meter.
Normal continuity readings should be as follows.
Door Opened
Door Closed
0
Ω
(Close)
Ω
(Open)
5.3. 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.
5.4. key board membrane
(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.
5 COMPONENT TEST PROCEDURE
14
NN-SD698S / NN-ST678S / NN-ST658W
Summary of Contents for NN-SD698S
Page 2: ...2 NN SD698S NN ST678S NN ST658W ...
Page 3: ...3 NN SD698S NN ST678S NN ST658W ...
Page 5: ...1 SCHEMATIC DIAGRAM 5 NN SD698S NN ST678S NN ST658W ...
Page 23: ...8 6 How to check the semiconductors using an OHM meter 23 NN SD698S NN ST678S NN ST658W ...
Page 24: ...9 EXPLODED VIEW AND PARTS LIST 9 1 EXPLODED VIEW 24 NN SD698S NN ST678S NN ST658W ...
Page 33: ...10 DIGITAL PROGRAMMER CIRCUIT 10 1 NN SD698S 33 NN SD698S NN ST678S NN ST658W ...
Page 34: ...34 NN SD698S NN ST678S NN ST658W ...
Page 35: ...10 2 NN ST678S 35 NN SD698S NN ST678S NN ST658W ...
Page 36: ...36 NN SD698S NN ST678S NN ST658W ...
Page 37: ...10 3 NN ST658W 37 NN SD698S NN ST678S NN ST658W ...
