Troubleshooting for start signal faults

The Temperature fault Light Emitting Diode (LED) and the System Fault LED flash alternately when the system receives a Start signal from the torch at the same time that the power switch is set to ON (I). This fault can prevent the torch from firing a plasma arc.

Fault codes and fault LEDs

Fault code Fault LEDs Torch LED Description Stops the system from operating?
None The images shows the Temperature fault Light Emitting Diode flashing. The image shows the System Fault Light Emitting Diode flashing.

Flash alternately

 The image shows the torch Light Emitting Diode illuminated yellow.

Yellow

 The plasma power supply received a signal to start cutting at the same time that the power switch was set to ON (I). This condition is also referred to as a "stuck start." Yes. A quick restart is necessary.

Corrective action: quick restart

  1. Do you have a hand torch or a machine torch? OptionDescription
    Hand torch: Release the torch trigger.
    Machine torch: Set the Start signal to off.
  2. Do a quick restart of the plasma power supply.
  3. If the Temperature fault LED and the System Fault LED continue to flash alternately, do the corrective action for hand torches or machine torches.

Corrective action for hand torches

  1. If possible, do a test with a different hand torch that is known to operate correctly.
  2. Make sure that the torch is set to the green "ready to fire" position.
  3. Do the Temperature fault LED and the System Fault LED continue to flash alternately? OptionDescription
    If yes... Continue with step 7.
    If no... Continue with the next step.
  4. Disconnect the torch from the plasma power supply.
  5. Make sure that the torch trigger is not being pulled, and measure the resistance between pin 6 and pin 7 in the torch connector.
    The image shows pin 6 and pin 7 in the torch connector.
  6. Is the resistance very low? OptionDescription
    If yes...
    • Do a check for short circuits in the torch lead. Replace the torch lead if the wires in it are short-circuited.
    • Do a check for short circuits in the trigger switch assembly. Replace the trigger switch if it is short-circuited.
    If no... Reconnect the torch to the plasma power supply, and continue with the next step.
  7. Do the Temperature fault LED and the System Fault LED continue to flash alternately? OptionDescription
    If yes... Replace the power Printed Circuit Board (PCB).
    If no... Disconnect the torch from the plasma power supply, and continue with the next step.
  8. Measure the resistance between pin 6 and pin 7 in the torch connector while you are pulling the torch trigger.
  9. Is the resistance very high? OptionDescription
    If yes...
    • Do a check for open circuits in the torch lead. Replace the torch lead if there are open circuits.
    • Do a check of the trigger switch for open circuits. Replace the trigger switch if there are open circuits.
    If no... Continue with the next step.
  10. If the torch continues to not fire a plasma arc, and gas does not flow from the torch, do a check for continuity between the torch and the plasma power supply:
    1. Put the torch on its side, and remove the left side of the torch shell.
    2. Do a check for continuity between pin 4 on the torch PCB (red wire) and pin 3 at J19 on the power PCB.
    3. Do a check for continuity between pin 5 on the torch PCB (orange wire) and pin 2 at J19 on the power PCB.
    4. If you do not have continuity between the pins, replace the power PCB.
      The image shows the pins for continuity in the torch and plasma power supply.

Corrective action for machine torches and the CNC

  1. If possible, do a test with a different machine torch that is known to operate correctly.
  2. Make sure that the torch is set to the green "ready to fire" position.
  3. Do the Temperature fault LED and the System Fault LED continue to flash alternately? OptionDescription
    If yes... Continue with the next step. The problem can be with the Computer Numerical Control (CNC) or with the machine interface cable.
    If no... Continue with Corrective action for machine torches and the plasma power supply. There can be a problem with the power PCB or the machine interface receptacle in the plasma power supply.
  4. Disconnect the machine interface cable from the rear of the plasma power supply.

    This is the 14-pin cable that connects the plasma power supply to the CNC.

  5. Do a quick restart.
  6. If the fault code goes away and the system operates correctly, restart the CNC.

    This can remove a start signal if there is one pending.

  7. Connect the machine interface cable to the plasma power supply, and do a quick restart.
  8. If you continue to see the same fault condition, disconnect the machine interface cable from the plasma power supply again.
  9. Do a check for continuity on pin 3 and on pin 4 in the machine interface cable connector.
    The image shows the pins for plasma start on the machine interface cable.
  10. Is there continuity on both pins? OptionDescription
    If yes... There can be a problem with the CNC or with the cable. Continue with the next step.
    If no... There can be a problem in the plasma power supply. Continue with Corrective action for machine torches and the plasma power supply.
  11. Do a check for open circuits in the machine interface cable between pin 3 and the CNC and between pin 4 and the CNC.
  12. Are the signals open? OptionDescription
    If yes... There can be a problem with the CNC. Go to the last step.
    If no... There can be a problem with the cable. Continue with the next step.
  13. Disconnect the machine interface cable from the CNC.
  14. Are there short-circuited wires in the cable? OptionDescription
    If yes... Replace the machine interface cable.
    If no... Continue with the next step.
  15. If there is not a problem with the machine interface cable, speak to a support technician for the CNC to identify possible problems that can prevent the torch from firing.

Corrective action for machine torches and the plasma power supply

  1. Set the power switch to OFF (O), and disconnect the power cord from the power source.
  2. Remove the plasma power supply handle and cover.
  3. Remove the component barrier.
  4. Do a check for continuity on pin 1 (red) and pin 2 (black).
    The image shows the machine interface pins for plasma start on the power Printed Circuit Board.
  5. Is there continuity on both pins? OptionDescription
    If yes... There is possibly a problem with the wiring harness for the machine interface receptacle. Replace the machine interface receptacle with the voltage divider PCB assembly (223476).
    If no... There is possibly a problem with the power PCB. Replace the power PCB.