OmniTurn G3 CNC: Spindle Won't Start
Legacy Inverter Spindle Drive (TB1)

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Most likely cause is open Spindle Off/Auto Switch, or open Palm Box E-Stop switch, or bad connection between these one of these swiches and Connect Card or TB1.

Initial Tests

• Check the Spindle Off/Auto switch; even if it's in Auto, switch it between Off and Auto a few times to exercise the contacts.
• Check the Spindle Override pot; again, even if it's at 100%, turn it down to zero and back to 100 a few times to clean the contacts.
• Engage and disengage the Palmbox E-Stop switch; spindle enable voltage goes through one set of contacts on this switch.
• Use MDI mode and try both M03 and M04 to confirm it doesn't start in either direction.
  If spindle starts in either M03 or M04, note which, and continue troubleshooting here.
• Verify that the spindle is not turning at all.
  If it's turns slowly in either direction with M03 or M04, and stops with M05, continue troubleshooting here.

Spindle Drive Cabinet

After these tests, if the spindle still does not start, you'll need to check some things inside the spindle drive cabinet:(For reference, here is PDF of spindle cabinet components)

• Set the CNC control off, and turn the spindle drive cabinet switch to OFF.
• Open the cabinet door, then use a small wrench or pliers to turn the 1/4" shaft to set the spindle drive power on.
• Set the CNC power on and turn on servos.

Relays

Any time the control is on with the servos on, the leftmost relay in the rowRelays in Spindle Cab at the top of the electrical panel in the spindle drive box must be lit. The relays in the very oldest (pre-1995) spindle drive boxes don't have lights. If your machine is that old, you will need to use a voltmeter to verify relay status: ON = 12VDC betweeen relay contacts 13 and 14; OFF = 0VDC between relay contacts 13 and 14.

The spindle gets its start command through the M03 or M04 relay in the spindle drive box.

• Use MDI to issue M03 and see if the LED on M03 relay lights; do the same for M04.
  If the LED's light, continue troubleshooting here.
  If they don't light, you need to check some voltages on terminal strip TB1.

Terminal Strip TB1

The signals come down from the control to the long terminal strip that runs down the left side of the electrical panel (called TB1). Terminal 1 is the top terminal on the strip. If the relays are not turning on (as indicated by the LED lights in the relays), you'll need to check some voltages on that strip. The control and servos need to be on to check these.

Before measuring voltages issue M05 from MDI mode. This is to verify that neither M03 or M04 are engaged.

• TB1-8 to TB1-9: 12 volts DC. This is the "Control Ready" voltage; it shows that the servos are on. If this is not 12 volts DC, but you can jog the axes, there is an issue with your voltmeter. If you cannot jog, troubleshoot Can't Turn Servos On.
• TB1-8 to TB1-3: 12 volts DC. This is the "Spindle Auto" voltage; it shows that Spindle Off/Auto switch on the control front panel is set to Auto. If it's not there it could be a bad Off/Auto switch or a bad connection between the switch and the connect card or pin 12 in the MISC cable.
• TB1-8 to TB1-4: 12 volts DC. This is the "Spindle Auto" voltage through the Palm Box Emergency Stop switch. If you have 12 volts TB1-8 to TB1-3 but not TB1-8 to TB1-4, the Palm Box E-Stop switch is probably the culprit.