3765

Common Causes

• Broken wire in the spindle vibration sensor circuit
• Sensor lead pinched or fatigued where the spindle head moves or where the cable is clamped
• Loose or corroded connector at the vibration sensor or monitor input
• Failed vibration sensor element causing an open loop

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code 1 = The spindle vibration sensor wire/circuit is open or broken.
2. 2Confirm the screen shows Code 1, which the manual defines as a broken wire in the spindle vibration sensor circuit.
3. 3Trace the vibration sensor cable from the spindle head area back toward the monitor/input, looking for cuts, oil-soaked insulation, tight bend points, or a cable pulled at a clamp.
4. 4Lock out power before disconnecting the sensor, then inspect the sensor connector pins for pushed-back contacts, coolant, or corrosion.
5. 5Check continuity of the sensor loop end-to-end; an open reading localizes the fault to the cable or sensor rather than the CNC input.
6. 6Repair the damaged wiring or replace the spindle vibration sensor if the open is inside the sensor, then secure the cable so spindle motion cannot flex it at the failure point.
7. 7If the circuit measures good but the alarm remains, record alarm C 3765 with Code 1 and contact Okuma service.