Philips NN-SN968B, Servise Manual

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Discharging the high voltage capacitors
WARNING
There is high voltage present with high current capabilities
in the circuits of the primary and secondary windings, choke
coil and heat sink of the inverter. It is extremely dangerous
to work on or near these circuits with the oven energized.
DO NOT measure the voltage in the high voltage circuit
including the filament voltage of the magnetron.
WARNING
Never touch any circuit wiring with your hand or with an
insulated tool during operation.
3.3. Part replacement.
When troubleshooting any part or component is to be replaced,
always ensure that the power cord is unplugged from the wall
outlet.
3.4. When the 20A fuse is blown
due to the malfunction of the
monitor interlock switch:
WARNING
When the 20A 120V fuse is blown due to the malfunction of
the monitor interlock switch, replace all of the components
(primary latch switch, monitor interlock switch and power
relay RY1).
1. This is mandatory. Refer to “measurements and
adjustments” for the location of these switches.
2. When replacing the fuse, confirm that it has the
appropriate rating for these models.
3. When replacing faulty switches, be sure the mounting
tabs are not bent, broken or deficient in their ability to
hold the switches.
3.5. Avoid inserting nails, wire etc.
through any holes in the unit
during operation.
Never insert a wire, nail or any other metal object through the
lamp holes on the cavity or any holes or gaps, because such
objects may work as an antenna and cause microwave
leakage.
3.6. Verification after repair
1. After repair or replacement of parts, make sure that the
screws of the oven, etc. are neither loosen or missing.
Microwave energy might leak if screws are not properly
tightened.
2. Make sure that all electrical connections are tight before
inserting the plug into the wall outlet.
3. Check for microwave energy leakage. (Refer to procedure
for measuring microwave energy leakage).
CAUTION OF MICROWAVE RADIATION LEAKAGE
USE CAUTION NOT TO BECOME EXPOSED TO
RADIATION FROM THE MICROWAVE MAGNETRON OR
OTHER PARTS CONDUCTING MICROWAVE ENERGY.
IMPORTANT NOTICE
1. The following components have potentials above 2000V
while the appliance is operated.
•
Magnetron
•
High voltage transformer (Located on inverter (U))
• High voltage diodes (Located on inverter (U))
•
High voltage capacitors (Located on inverter (U))
Pay special attention to these areas.
2. When the appliance is operated with the door hinges or
magnetron installed incorrectly, the microwave leakage
can exceed more than 5mW/cm
2
. After repair or
exchange, it is very important to check if the magnetron
and the door hinges are correctly installed.
3.7. Sharp edges
CAUTION
Please use caution when disassembling or reassembling
internal parts. Some exposed edges may be sharp to the
touch and can cause injury if not handled with care.
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NN-SN968B / NN-SN968BT