GE JKP18 Series, Technical Service Manual

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Magnetron Test
1. Isolate the magnetron from the high-voltage
circuit by disconnecting the magnetron con-
nector.
2. Check for continuity across the magnetron
filament leads with an ohmmeter. Resistance
should be less than 1 ohm.
3. Check for continuity between one magnetron
filament lead and the chassis ground. This
test should indicate an infinite resistance. If
there is continuity, the magnetron is grounded
and must be replaced.
4. Check for continuity between the other magne-
tron filament lead and the chassis ground.
This test should indicate an infinite resistance.
If there is continuity, the magnetron is
grounded and must be replaced.
Power output of the magnetron can be measured
by conducting a Performance Test (see Microwave
Performance Test).
Microwave Magnetron Fan
The microwave must be removed from the oven to
service the magnetron fan.
The magnetron fan operates whenever the mag-
netron is operating. The magnetron fan will also
operate if the fan thermal switch reaches 158 °F.
The fan draws external air into the component
compartment through holes in the rear panel.
The air is circulated through the magnetron air
vanes, providing cooling for the magnetron. The
air also circulates through the oven cavity to
remove steam and vapors given off when heating
food.
Microwave Magnetron TCO
(Thermal Cutout)
Obtain access to the magnetron TCO by placing
the control panel in the service position.
OPEN - 302 °F
CLOSE - 140 °F
The magnetron TCO is mounted on the top of the
magnetron with 2 Phillips screws. This position
allows the TCO to sense the temperature of the
magnetron and will open, shutting the unit down if
excessive heat (302 °F) is detected. The TCO will
Magnetron
Fan
Magnetron TCO