Test 1
A.
Place 1 liter of water load into oven cavity.
B.
Unplug 2 pin H.V. lead wire connector CN703 from magnetron
tube.
C.
Program oven at High power for 1 minute and press start.
1. After approximately 23 seconds, oven stops.
2. During oven operation, input current is approx. at 0.5 to
1.0A. If both 1 and 2 are OK, please proceed to test 2.
Test 2.
Continued from Test 1
A. Unplug 3 pin connector, CN701 & CN703 remains unplug.
B. Set oven at High power for 1 minute and start.
1. After approximately 3 seconds, oven stops.
2. During oven operation, input current is approximately less
than 0.4A.
If both 1 and 2 are OK, the Inverter Power Supply (U) can be
determined OK.
COMPONENT TEST PROCEDURE
CAUTION
1. High voltage is present at the high voltage terminal of
the High Voltage Inverter (U) including aluminum heat
sink during any cook cycle.
2. It is neither necessary nor advisable to attempt mea-
surement of the high voltage.
3. Before touching any oven components, or wiring,
always unplug the oven from its power source and
discharge the high voltage capacitors.
NEW. H.V.
1. Primary Latch Switch, Secondary (Secondary Latch
Switch and Power Relay B) Interlocks.
(A) Unplug the lead connectors to Power Relay B and verify continuity
of the power relay B 1-2 terminals.
(B) Unplug lead connectors to Primary Latch Switch and Secondary
Latch Switch.
(C) Test the continuity of switches at door opened and closed positions
with ohm meter (low scale).
Normal continuity readings should be as follows.
2. Short Switch & Monitor
(A) Unplug lead wires from Inverter Power Supply (U) primary terminals.
(B) Connect test probes of ohm meter to the disconnected leads which
were connected to Inverter Power Supply (U).
(C) 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 Closed
0
Ω
(close)
0
Ω
(close)
5. Inverter Power Supply (U)
DO NOT try to REPAIR this H.V. Inverter power supply
(U).Replace as whole H.V. Inverter(U) Unit.
Primary Latch Switch
Secondary Latch Switch
Power Relay B
Door Closed
∞
Ω
Door Opened
0
Ω
- 17 -
3. Magnetron
Continuity checks can only indicate an open filament or a shorted
magnetron. To diagnose for an open filament or shorted magne-
tron.
(A) Isolate magnetron from the circuit by disconnecting the leads.
(B) A continuity check across magnetron filament terminals should
indicate one ohm or less.
(C) A continuity check between each filament terminal and magnetron
case should read open.
ANTENNA
COOLING
FIN
MAGNETRON
CASE
HIGHEST
OHM
SCALE
FILAMENT
TERMINALS
04-031M
0
Ω
-1
Ω
RX1
SCALE
ANTENNA GASKET
HEAT SINK
CHOKE COIL
CURRENT
TRANSFORMER
RESISTOR
SAND BAR
PCB
FILM CAPACITORS
VARISTOR
PRIMARY WINDINGS
SECONDARY
WINDINGS
HIGH VOLTAGE
DIODES
DO NOT TOUCH
SYMPTOM
Oven stops in 23
seconds after
started.
Unplug CN703
INPUT AMPERE
0.5 to 1A
HIGH BOLTAGE
TRANSFORMER
DO NOT TOUCH (HOT/HIGT VOLTAGE)
Door Opened
∞
Ω
(open)
∞
Ω
(open)
∞
Ω
(open)
4. Membrane key board (Membrane switch assembly)
Check continuity between switch terminals, by tapping an appropri-
ate pad on the key board. The contacts assignment of the
respective pads on the key board is as shown in digital programmer
circuit.
∞
Ω
(open)
SYMPTOM
Oven stops in 3
seconds after
started.
Unplug CN701
INPUT AMPERE
< 0.4A
