ADC 450428 service manual Main Door Condition, Microprocessor Computer

c.If no voltage is present at J7 9-pin connector no. 4 to ground, but voltage is present at no. 3 to ground. The problem is a faulty switch, wires or termination between J7 to J8 and J8 to the lint switch no. 20 and 21.

d.If no voltage is present at J7 9-pin connector no. 3 to ground, then voltage should not be present at no. 5 to ground. Replace the board.

6.Main Door Condition

NOTE: Make sure main door and lint door are closed. Also, if checking either switch, the plunger must be depressed.

a.Check L.E.D. (light emitting diode) input light “MAIN” on the component side of the computer. If the light is on, replace the computer.

b.Check voltage (24 VAC) from J7 9-pin connector no. 5 to ground. If voltage is present, check no. 6 to ground. If voltage is present, replace board.

c.If no voltage is present at J7 9-pin connector no. 6 to ground, but voltage is present at no. 5 to ground. The problem is a faulty switch, faulty wires or terminations J7 to J8. J8 to J5 and J5 to main door switch no. 31 and no. 32.

7.“No Heat” drive and blower motors run, display reads normal (gas models).

a.Check L.E.D. (light emitting diode) input light “HT1” on the component side of the computer. If the light is on replace the board.

b.If the L.E.D. (light emitting diode) input light “HT1” on the component side of the computer is on and there is no voltage to the HSI (Hot Surface Ignition) module “w” the display will read “BURNER CONTROL FAIL.” The problem is faulty wires or terminations between microprocessor and HSI (Hot Surface Ignition) module.

c.If voltage is present on the HSI (Hot Surface Ignition) module “w” to ground. Check voltage at the gas valve if voltage is present across the two (2) “yellow” wires at the gas valve and the gas supply is on then the fault is that of the gas valve.

8.Microprocessor (Computer)

a.Replace the temperature sensor underneath the tumbler (basket) on a bracket (the bullet shaped device).

b.If it still reads “TEMP SENSOR FAIL CHECK TEMP SENSOR FUSE,” unplug J3 4-pin connector from the temperature sensor bracket. Also, unplug the microprocessor J14 4-pin connector from the computer board. Take a continuity reading from J14 no. 1 to J3 no. 1, then from J14 no. 2 to J3 no. 2.

If there is no continuity, check for break in wire, a short to the ground, loose terminations, or even replace the wire.

If there is continuity, computer board is faulty.

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