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 power.
16500055
October 2014
©2014 ACP, Inc.
2
Illustration
Component
Test
Results
Thermal Cutout
Disconnect all wires from TCO.
Measure resistance across terminals.
Oven TCO (bottom left rear)…………..
Cavity TCO (top left)……………………
Top
Cavity TCO (top center)…………..
Magnetron TCO (2) (on magnetron) .....
Open at 350° F (177° C)
Open at 300° F (149° C) and
Closed at 257° F (125° C)
Open at 300° F (149° C) and
Closed at 257° F (125° C)
Open at 300° F (149° C) and
Closed at 257° F (125° C)
Diode
ALWAYS DISCHARGE CAPACITOR !
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:
Ohmmeter must contain a
battery of 6 volts minimum.
MT2
MT1
GA TE
Triac (40A)
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 60
Ω
Infinite
Ω
Infinite
Ω
Triac 1 (front) is for Convection Motor
Triac 2 (middle) is for Convection Heater
Triac 3 (rear) is for Microwave
In cook mode measure voltage from:
MT1 to Gate
………………………………
MT1 to MT2
………………………………
0.8 VAC when energized. If no
voltage, check H.V. board and wiring.
0VAC
Capacitor
ALWAYS DISCHARGE CAPACITOR !
Remove wires from capacitor terminals and
connect ohmmeter on highest resistance
scale or capacitance meter to terminals.
Also check between each terminal and
capacitor case.
Capacitance Meter:
JET514 = .82µ
Ohm Meter 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 (Triac)
Snubber is comprised of a resistor and
capacitor in series. Disconnect wires to
Snubber. Measure resistance across
terminals.
Using an ohmmeter, a slight deflection
may be seen then Infinite.
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.
Blower Motor
Remove all wires from motor.
Measure resistance between:
Orange and Yellow terminals ......................
Approximately 25
Ω
Stirrer Motor
Remove all wires from terminals.
Measure resistance
across terminals……..
Approximately 12K
