Panasonic NN-V673SBBPQ Service Manual page 26

WARNING FOR INVERTER POWER SUPPLY (U) GROUNDING
Check the high voltage inverter power supply circuit grounding. The
high voltage inverter power supply circuit board must have a proper
chassis ground, the inverter grounding bracket must be connected
to the chassis. If the inverter board is not grounded it will expose
very high voltages and cause extreme DANGER! Be sure that the
inverter circuit is properly grounded via the inverter earth bracket.
WARNING! DISCHARGE THE HIGH VOLATGE CAPACITORS
For about 30 seconds after the oven is turned off, an electric charge
remains in the high voltage capacitors in the inverter power supply
circuit board.
When replacing or checking parts, remove the power plug from the
outlet and short the inverter output terminal of the magnetron
filament terminals to the chassis ground with an insulated handle
screwdriver to discharge. Please be sure to touch the chassis
ground side first and then short to the output terminals.
HV Inverter warning
Figure 2
Grounding of the inverter circuit board
Figure 3
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