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.
Illustration | Component | Testing | Results | ||
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| Thermal cutout | Disconnect all wires from TCO. |
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| Measure resistance across terminals. | Closed at 32°F (0°C) and |
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| Cavity TCO | |
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| Magnetron TCO | Opens at 230°F (110°C) |
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| Closed at 140°F (60°C) and | |
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| Opens at 320°F (160°C) |
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| Diode | Discharge Capacitor | Infinite resistance should be |
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| measured in one direction and 50KΩ |
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| Remove diode lead from capacitor and | or more in the opposite direction. |
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| connect ohmmeter. | NOTE: Ohmmeter must contain a |
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| Reverse leads for second test. | |
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| battery of 6 volts minimum. | |
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| Capacitor | Discharge Capacitor |
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| Remove wires from capacitor terminals | Between Terminals: Meter should |
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| and connect ohmmeter, set on highest | momentarily deflect towards zero |
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| resistance scale to terminals. | then return to over 5 MΩ. If no |
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| deflection occurs, or if continuous |
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| deflection occurs, replace capacitor. |
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| Also check between each terminal and |
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| capacitor case. | Terminal to Case: Infinite resistance |
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| Magnetron | Discharge Capacitor | Between Terminals: Less than 1 Ω |
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| Remove wires from magnetron and | Each terminal to ground measures |
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| connect ohmmeter to terminals. Also | Infinite resistance. |
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| check between each terminal and | Note: This test is not conclusive. If |
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| ground. | oven does not heat and all other |
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| components test good replace the |
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| magnetron and retest. |
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| Blower motor | Remove all wires from motor. |
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| Measure resistance across coil | Approximately 14 – 21 Ω |
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| Stirrer motor | Remove all wires from motor. |
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| Measure resistance across terminals .... | Approximately 3 – 3.5 KΩ |
Secondary |
| Transformer | Discharge Capacitor |
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| Remove all wires from terminals. |
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| Filament |
| Measure resistance from: |
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| Less than <1 Ω | |
Primary |
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| Primary | |
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| Filament | Less than <1 Ω | |
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| Secondary to Ground screw on |
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| transformer stack | Approximately 100 – 120 Ω |
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| Noise filter board | Power In terminals | 120 VAC |
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| Power Out terminals | 120 VAC |
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| If no power in, check power outlet. |
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| If no power out, check fuses. |
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| 6 minute timer | Remove leads from timer contact | If timer does not indicate readings |
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| terminals. | below, replace timer. |
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| Measure resistance of following | Infinite Ω |
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| BELL |
| terminals: | Approximately <1 Ω |
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| 1 to 2⎯Timer in OFF position | Approximately 11 KΩ (timer motor) | |
4 | 3 | 2 1 |
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| 1 to 2 Timer in ON position |
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| 3 to 4⎯Timer in OFF or ON position |
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20 | 16023293 Rev. 0 | ©2004 Maytag Services |
