American Dryer Corp AD-200 service manual Electrical Troubleshooting

SECTION VII

ELECTRICAL TROUBLESHOOTING

1.Microprocessor Display Power Circuit

Theory of the Microprocessor Display Power Circuit:

The power distribution block is where the incoming voltage is applied to. L1 and L3 are branched off to supply the 208-240 volts single phase to the two .5 amp slo-blo fuses. This voltage might be stepped down by a step down transformer if the incoming voltage is 380 volts or higher. This 208-240 volts is then supplied to the computer.

Path of Voltage for the Microprocessor Display Power Circuit:

The incoming voltage to the machine is applied to the power distribution block lines L1, L2, and L3. From there this voltage travels to the contactors; drum and blower motor. L1 and L3 branch off of this voltage and travel to a step down transformer if the incoming voltage is 380 volts or higher. If your incoming voltage is 208/ 240 volts this transformer is not needed. After the transformer (if applicable) the L1 and L3 lines are both fused with .5 amp slo-blo fuses. The L1, L3 voltage now travels to the little 3 position terminal block (A, B, C) letters A and B, then to the J3 connector numbers 7 and 13, from there to the J1 connector 7 and 13, finally to the microprocessor 15 pin connector pin #'s 7 and 13. This is the path of voltage for the microprocessor's display. Always check the two .5 amp fuses first, these are the most common parts to fail when checking this circuit.

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