Panasonic NN-CT577SEPG Service Manual page 8

The aluminium heat sink becomes very hot when the
inverter circuit operates. Never touch this heat sink
figure 4 HV Inverter warning
WARNING
INVERTER POWER SUPPLY GROUNDING
Check the high voltage inverter power supply circuit
grounding. The high voltage inverter circuit board
must be connected to the microwave oven chassis. If
the inverter board is not grounded it exposes very high
voltages and causes extreme DANGER! Ensure that the
inverter circuit is properly grounded via the inverter
earth bracket.
figure 5 Grounding of the inverter circuit board
WARNING! DISCHARGE THE HIGH VOLTAGE CAPACI-
during operation and allow time for it to cool down
before servicing the microwave oven.
TORS
For about 30 seconds after the oven is turned off, an
electric charge remains in the high voltage capacitors
on the inverter circuit board.
figure 6 Discharging the high voltage capacitors
1. Before replacing or testing parts discharge these
high voltage capacitors by shorting the inverter
ouput terminal to the microwave oven chassis
2. Remove the power plug from the mains outlet
3. Ensure that the high voltage lead is connected to
the inverter output terminals and the magnetron
input terminals.
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