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Examine wires 434 and 436 for 24 Vdc on wires J10.1 and J10.3, respectively.
Start the spindle and listen for a soft, audible click on the control board. If you hear this click (from a relay contact on the board), the machine control board is functioning properly. If you don't hear the click:
Verify that there's 24 Vdc measured from wire 400 to wire 434. Make a jumper wire and, carefully,
momentarily jumper wires 434 and 436.If contactor K2 pulls in (you will hear an audible clunk) while you have the jumper on but drops out as soon as you remove the jumper, review the previous solutions to inspect why the K2 isn’t holding.
If K2 stays powered on, the control board is not passing the run signal to the circuit. The control board passes 24 Vdc from wire 434 to 436 via a relay to create the start pulse. Measure wire 434 for 24 Vdc power. If present, the control board or wire 436 connected to J10.3 is defective. Power off the machine, and jumper J10.1 to J10.3 Power on the machine and check the VFD for a display. If the VFD reads rdy, the control board is defective. If not, wire 436 may be broken. Lift the connections of wire 436 at the control board and K2 and measure continuity.
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