Component Testing Procedures - Amana UCRC518T2 Service Manual

Component Testing Procedures

To avoid risk of electrical shock, personal injury, or death, disconnect power to oven and discharge
capacitor before servicing, unless testing requires it.
Illustration
Thermal cutout
protectors
Diode assembly
Triac
MT2
MT1 GA TE
Capacitor
Snubber assembly
Magnetron
Blower motor
Line filter
Line
Load
Earth
Stirrer motor
Type A
Type B
Wire harness
RS5320010 Rev. 1
!
Component
Disconnect all wires from TCO.
Measure resistance across terminals.
1800, 1400, and 1000 Watt models
Cavity TCO
Magnetron TCO
Discharge Capacitor
Remove diode lead from capacitor and
connect ohmmeter.
Reverse leads for second test.
Disconnect wires to triac.
Measure resistance from:
MT1 to MT2
MT1 to Gate
MT2 to Gate
All terminals to earth
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.
Disconnect wires to snubber.
Measure resistance across terminals.
Discharge Capacitor
Remove wires from magnetron and connect
ohmmeter to terminals. Also check
between each terminal and earth.
Remove all wires from motor.
Measure resistance across coil.
Line to Line
Load to Load
Line to Load
Any terminal to Earth
Remove all wires from motor.
Measure resistance across terminals.
Test continuity of wires.
WARNING
Testing
15
Results
Opens at 104°C
Open at 149°C and closed at 135°C
Infinite resistance should be measured
in one direction and 50,000 Ω or more
in the opposite direction.
NOTE: Ohmmeter must contain a
battery of 6 volts minimum.
Caution - Do not operate oven with
wire to terminal MT2 removed.
Infinite
Approximately 40 Ω or more
Infinite
Infinite
Between Terminals: Meter should
momentarily deflect towards zero then
return to over 5 MΩ. IF no deflection
occurs, or if continuous deflection
occurs, replace capacitor.
Terminal to Case: Infinite resistance
Infinite
Between Terminals: Less than 1 Ω
Each terminal to earth 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.
Approximately 30 Ω
.8 M Ω
.8 M Ω
Continuity
Infinite
Type AApproximately 3400 Ω
Type BApproximately 12 KΩ
Indicates continuity