The main AC fuse would blow if there is a direct short across the AC line. This could be caused by a:
To check - unplug the control box AC power cable (2 wire) from the control. Turn on power, if fuse blows, I/O PC Board is defective. If fuse does not blow, I/O PC Board is OK.
2. Defective Controller (-3462)
To check - connect the control box AC power cable (2 wire) to the control, and unplug motor/clutch connector from control box. Turn on power, if fuse blows, Control Box is defective. If fuse does not blow, Control Box is OK.
3. Defective Controller (-3426) and Motor/Clutch Assembly (-3545) --- motor (shorted out) causing control to be defective.
To check - unplug the motor/clutch connector from the control. Check resistance of Motor/Clutch wires on connector - Motor (middle 2 wires) should read 20 to 70 ohms. If incorrect (low reading), motor is defective. Clutch (outside 2 wires) should read approximately 1200 ohms. If incorrect, clutch is defective.
If Control showed defective in step 2, and Motor/Clutch showed defective in step 3, then both would need to be replaced.
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