Microwave Testing Procedures
!
WARNING
To avoid risk of electrical shock, personal injury or death; disconnect power to oven before servicing, unless
testing requires it.
26
16022821 Rev. 0
©2004 Maytag Appliances Company
Illustration Component
Test
Procedure
Results
Oven light and socket
Test continuity of receptacle terminals .
Measure voltage at oven light...............
Indicates continuity with bulb screwed in.
120 VAC; see wiring diagram for terminal
identification. If no voltage is present at
oven light check wiring.
Transformer
Discharge Capacitor
Remove all wires from terminals.
Measure resistance from:
Primary Terminals................................
Secondary Terminals ...........................
Less than 1
Ω
Approximately 85
Ω
Turntable
Remove all wires from terminals.
Measure resistance from:
Terminal to terminal................................
Approximately 2238
Ω
Magnetron
Discharge Capacitor
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
retest.
Thermal cutout
Disconnect all wires from TCO.
Measure resistance across terminals.
Magnetron TCO ...................................
Cavity TCO ..........................................
Open at 230
°
F (110
°
C) and
closed at 194
°
F (90
°
C)
Opens at 320
°
F (160
°
C)
Primary
Secondary
Monitor
Interlock switch
Disconnect wires to switch.
With door open measure resistance
from:
Monitor...........................................
Secondary .....................................
Primary ..........................................
With door closed measure resistance
from:
Monitor ....................................................
Secondary...............................................
Primary ...................................................
Indicates continuity
Infinite
Infinite
Infinite
Indicates continuity
Indicates continuity
Capacitor
Discharge Capacitor
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
Fan Motor
Remove all wires from motor.
Measure resistance across coil ...............
Approximately 63.6
Ω
