
Component Testing Procedures
!
WARNING
To avoid risk of electrical shock, personal injury, or death, disconnect power to oven and discharge capacitor
before servicing, unless testing requires it.
RS2220001 Rev. 2
17
Illustration
Component
Test
Results
Thermal Cutout
B5684106
B5795306
B5684118
Disconnect all wires from TCO.
Measure resistance across terminals.
Magnetron TCO (.250
terminals)
Cavity TCO
Control TCO (.187
terminals)
Open at 280
°
F and closed at 180
°
F
Opens at 262
°
F (128
°
C)
Open at 280
°
F and closed at 180
°
F
Diode
Discharge Capacitors
Remove diode lead from capacitor and
connect ohmmeter.
Reverse leads for second test.
Infinite resistance should be measured
in one direction and 50K
Ω
or more in
the opposite direction.
NOTE: Analog meter must contain a
battery of 6 volts minimum.
MT2
MT1
GA TE
Triac
Disconnect wires to triac.
Measure resistance from:
MT1 to MT2
MT1 to Gate
MT2 to Gate
All terminals to ground
Caution - Do not operate oven with
wire to terminal MT2 removed.
Infinite
Ω
Approximately 40
Ω
or more
Infinite
Ω
Infinite
Ω
Capacitor
Discharge Capacitors
Remove wires from capacitor terminals and
connect ohmmeter, set on highest
resistance scale to terminals.
Also check between each terminal and
capacitor case.
Between Terminals: Meter should
momentarily deflect towards zero then
return to over 5 M
Ω
. IF no deflection
occurs, or if continuous deflection
occurs, replace capacitor.
Terminal to Case: Infinite resistance
Snubber Assembly
Disconnect wires to snubber.
Measure resistance across terminals.
Infinite
Ω
Magnetron
Discharge Capacitors
Remove wires from magnetron and connect
ohmmeter to terminals. Also check
between each terminal and ground.
Between Terminals: Less than 1
Ω
Each terminal to ground measures
Infinite resistance.
Note: This test is not conclusive. If
oven does not heat and all other
components test good replace the
magnetron and re-test.
Antenna motor
Remove all wires from terminals.
Measure resistance from:
Terminal to terminal
Approximately 10,000
Ω
Blower Motor
Remove all wires from motor.
Measure resistance across coil.
Approximately 34
Ω
Lamp
240 VAC 40 Watts
Measure resistance
Approximately 120
Ω