36
Service & Parts Manual original Instructions
Part Number 32Z3810GB
Issue 1
TESTING
COMPONENT
S
1
2
3
HIGH VOLTAGE COMPONENTS
17
Power Transformer Test
17.1
Disconnect and isolate the oven from the
17.1.1
electricity supply.
Allow the oven to cool down.
17.1.2
Remove the oven casing.
17.1.3
Ensure that the High Voltage Capacitor is
17.1.4
discharged before commencing work.
Remove all connections from the Power
17.1.5
Transformer.
Using a D.M.M., check the resistance of the
17.1.6
windings. Results should be as follows:
Mains winding between tags, approx. 1.1 Ω
1
High Voltage winding, approx. 60 Ω
2
Filament winding between terminals, less than
3
1 Ω
Using a Megger, test the insulation resistance
17.1.7
between:
Primary winding and chassis, pass if reading is
●
over 10 MΩ
Filament winding and chassis, pass if reading is
●
over 10 MΩ
One end of the High Voltage winding is connected
to the chassis, so this is not tested.
High voltages and large currents are present at
the High Voltage Capacitor. It is very dangerous
to work near this part when the oven is on.
NEVER make any voltage measurements at the
High Voltage circuits, including the magnetron
filament.
Even when the oven is not cooking, the High
Voltage Capacitor has High Voltages present
because of the Soft Start circuit.
High Voltage Rectifier Test (Diode
17.2
Board)
Disconnect and isolate the oven from the
17.2.1
electricity supply.
Allow the oven to cool down.
17.2.2
Remove the oven casing.
17.2.3
Ensure that the High Voltage Capacitor is
17.2.4
discharged before commencing work.
Remove all connections from the High Voltage
17.2.5
Rectifier.
Using a Megger, test for continuity in both
17.2.6
directions. Results should be as follows:
Open circuit both ways - FAIL
●
Conducts one-way only - PASS
●
Short circuit both ways - FAIL
●
Conducts one way, leaks the other - FAIL
●
DANGER:
BEFORE REMOVING THE OVEN CASING, ISOLATE THE
OVEN FROM THE MAINS ELECTRICITY POWER SUPPLY;
SWITCH OFF, DISCONNECT OVEN PLUG FROM WALL
SOCkET, TURN OFF ISOLATOR SWITCH TO DISCONNECT
FIXED WIRED OVENS AND LOCk-OFF.
WARNING:
ALLOW OVEN TO COOL AND OBSERVE AND FOLLOW ALL
SAFETY PRECAUTIONS INCLUDING THOSE DESCRIBED
UNDER THE SAFETY REGULATIONS SECTION OF THIS
MANUAL BEFORE ATTEMPTING A SERVICE OR REPAIR.
CAUTION MICROWAVE EMISSIONS:
DO NOT BECOME EXPOSED TO EMISSIONS FROM THE
MICROWAVE GENERATOR OR PARTS CONDUCTING
MICROWAVE ENERGY.
WARNING:
ALWAYS DISCHARGE THE HT CAPACITORS BEFORE
WORkING ON THE OVEN USING A SUITABLY INSULATED
10MΩ RESISTOR.
