OmniTurn G4 CNC: Spindle Won't Start
Inverter Spindle Drive (TB1 or PWB)

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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 switches and Connect Card or TB1 / PWB.

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.
  Use diagnostic Alt-IAlt-I: Press & hold Alt key, then press I to verify that the input changes from 0 to 1 then back to 0 (0 = Auto).
  
  • If "Spin. Off/Auto" is stuck at "1" it could be a bad Off/Auto switch (p/n 995-12-104) or a bad connection between the switch and the front panel connect card, or between front panel connect card and motion card.
• 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.

Spindle Drive Cabinet

After these tests, if the spindle still does not start, you'll need to check some things in the spindle drive cabinet.
If your machine is pre-2011 with TB1, here is PDF of spindle cabinet components for reference.
If your machine is later model, with PWB, here is PDF of spindle printed wiring board for reference.

• 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 "No Fault" relay must be lit.
On machines equipped with TB1, this is the leftmost relay in the rowRelays in Spindle Cab at the top of the electrical panel in the spindle drive box. (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.)
On machines equipped with PWB, this is the bottom LED on the circuit card.Relays on PWB

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

• Use MDI to issue M03S100 and see if the LED for M03 lights; do the same with M04S100.
• If the LED's don't light, scroll down to Measure Voltage.
• If they DO light, verify that the spindle is not turning at all:
• If it's turning very slowly, there may be no spindle speed voltage at the drive; continue troubleshooting here.
• If the spindle starts in one direction but not the other, continue troubleshooting here.

Measure Voltage

On machines equipped with TB1,the signals come down from the control to the long terminal stripTB1 Terminal Strip that runs down the left side of the electrical panel. Terminal 1 is the top terminal on the strip.

On machines equipped with PWB, the signals come down from the control to HDR101.HDR101 and HDR101A Just below HDR101 is HDR101A, which provides access to all the of the pins. Terminal 1 is the right-most pin on that header.

If the relays are not turning on (as indicated by the LED lights in the relays or on the circuit card), you'll need to check some voltages, either on TB1 or on HDR101A. Set the CNC power on and turn on servos.

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

For machines equipped with TB1:

• TB1-8 to TB1-9:Meter between TB1-8 and TB1-9 should be 12 volts DC.
  This is the "Servos ON" 12V; 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.

For machines equipped with PWB:

• HDR101A-2 to HDR101A-9:Meter between HDR101A-2 and HDR101A-9 should be 12 volts DC.
  This is the "SO 12V" 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.