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Measure the Resistance on the Spindle Door Switch

ClosedOverview/Background Information

If you want background information on this problem, go to How Spindle Power is Controlled.

ClosedWhat Steps Have I Already Taken?

You've determined that:

  • The contactor C2 isn't powered on
  • The Machine Control Board isn't communicating with the PathPilot® controller
  • The variable frequency drive (VFD) isn't powered on
  • Wires 104 and 105 have voltage
  • Wire 105a on the Power Drawbar is operating properly
  • Wire 106 doesn't have voltage

Follow the Troubleshooting Steps to determine the cause of the spindle start failure.

Troubleshooting Steps

WARNING! Electrical Shock Hazard: You must power off the machine before making any electrical connections. If you don't, there's a risk of electrocution or shock.

  1. Power off the machine and the PathPilot® controller.

    1. Push in the Emergency Stop button on the operator panel, which disables movement of the axes and the spindle.
    2. From the PathPilot® interface, click Exit.
    3. Turn the Main Disconnect switch to Off on the side of the electrical cabinet.

    4. Follow correct lockout/tagout procedures.

      ClosedWatch how to lockout/tagout your machine

  2. Open the door of the spindle cover.

  3. Locate the spindle door switch.


  4. Locate the mounting bracket.


  5. Use a Phillips screwdriver to remove the spindle door switch from the mounting bracket.
  6. Remove the cover on the spindle door switch to expose the wires.
  7. Gently pull the wires are away from the spindle door switch terminals to see if they're properly connected. If they're not, connect them.

  8. Set the multimeter to OHMS mode.

    ClosedWatch how to use a multimeter

  9. Push in the plunger of the spindle door switch, and measure the resistance of the wires across the spindle door switch terminals.

Did the resistance change from 1 M (open circuit) to 0 ohms (closed circuit)?

  • Yes: Examine the wires going into the spindle door switch. If they're damaged: Replace them as necessary. If they aren't damaged: Tormach Technical Support for guidance on how to proceed.
  • No: This means that the spindle door switch is defective and must be replaced. Tormach Technical Support for guidance on how to proceed.