Component Testing Procedures - ACP AXP20 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 power.
Illustration Component
Thermal cutout
Diode
Triac
MT2
MT1 GA TE
Triac (TR1)
(TR2)
(TR3)
(TR4)
Capacitor
Snubber assembly
Magnetron
Cooling blower
motor
Stirrer motor
!
WARNING
Test
Disconnect all wires from TCO.
Measure resistance across terminals.
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 ground .............................
Measure voltage from:
MT1 to Gate
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 ground.
Measure voltage at motor
Measure resistance across leads..........
Remove all wires from terminals.
Measure resistance from:
Terminal to terminal.....................................
30
Results
Open at 300°F (149°C) and closed at
257°F (125°C)
Infinite resistance should be measured
in one direction and 50KΩ 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 15 Ω, then reverse
meter leads 30 Ω
Infinite
Infinite
0.8 VAC when energized. If no
voltage, check H.V. board and wiring.
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 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.
Approximately 24 vdc at incoming leads
Approximately 24K Ω at incoming leads
Approximately 29K Ω