JRC JMA-1032 Instruction Manual page 16

PRECAUTINS
xiv
CAUTION
When replacing magnetrons, make sure to shut off the main power
and let the equipment stand for more than 5 minutes to discharge
the high-voltage circuit.
Failure to comply may result in electrocution.
Make sure to take off your watch when your hand must get close
to the magnetron.
Failure to comply may result in damage to the watch since the
magnetron is a strong magnet.
When cleaning the display screen, do not wipe it too strongly with
a dry cloth. Also, do not use gasoline or thinner to clean the screen.
Failure to comply will result in damage to the screen surface.