OmniTurn G4 CNC:
No yellow "Control On" lamp or no display on monitor

No yellow "Control On" lamp:

The yellow power light indicates that the computer power supply is working. The 12V should come on when the system is turned on and the computer is working.
If the monitor displays the start-up information, replace the bulb
Rotate locking lever to access bulb. (#53 bayonet).

If there is also no display on the monitor, first do the following:

• Be sure there is power to the machine.
• Check that Check that disconnect
  Located on the left side of the GT75 on spindle cabinet is ON.
• Check that the CNC Control is plugged into socket
  Located on the back of the GT75. Worklamp power cord also plugs in here. back of machine.
• Check the fuse
  Located on the back of the CNC Control. on the back of the CNC control.
• Check the fuses
  Located in the spindle-drive cabinet.on step-down transformer in spindle cabinet. On GT75 machines, the worklamp will light if these fuses are ok.
• If any of these fuses are blown, the servo power supply bridge rectifier,
  Located in CNC, on Top Chassis. located on CNC top chassis,
  Located in CNC, on Top Chassis. is probably bad. P/N 995-15-002.
• If these fuses are OK, verify that upper fan is on and 2CR lamp
  Located in CNC, on Connect card. is lit.
• If fan is on and 2CR lamp is lit, replace the Control ON bulb.
  Rotate locking lever to access bulb. The monitor may also be bad. Go to "No Display on Monitor" below.
• If fan is not on and 2CR lamp is not lit, computer power supply or motherboard may be bad, or Control ON switch or connections to computer power supply may be bad. Click here to troubleshoot power supply.

No Display on Monitor:

The Control On lamp may have blown and not been replaced, and the monitor might also be bad. If the issue is a bad monitor, the control will boot up as normal, but there will be no display on the monitor.

To quickly determine if it’s just the monitor, set power on, then wait a minute, then press “N” key (to not backup program files). Wait a few seconds, then press the blue “Servos On” button. (The blue “Servos On” lamp may not come on: it may have blown and not been replaced). If you hear the servos come on, the control is probably OK, but the monitor may have failed. Click here to troubleshoot the monitor.