SV0406

Power down the machine completely and lock out electrical supply.

HIGH VOLTAGE PRESENT - Follow all lockout/tagout procedures before opening cabinets.

Inspect FSSB cable connections at both the CNC control unit and the affected servo amplifier. Check for bent pins, corrosion, or debris in connectors.

Firmly reseat both ends of the FSSB cable. If daisy-chained to multiple drives, check all intermediate connections in the bus chain.

Power up and monitor for alarm recurrence. If alarm persists, replace the FSSB cable with a known good cable and retest.

With machine locked out, verify 24VDC control power is present at the affected servo amplifier terminals (typically CX1A connector). Check for 24VDC ±10%.

Verify voltage levels with multimeter - improper voltage can damage components.

Check the DC bus voltage at the amplifier. Verify proper voltage is present from the PSM (Power Supply Module) or regenerative unit feeding the drive.

Inspect LEDs on the servo amplifier. No LEDs or irregular LED patterns indicate internal power failure or critical hardware fault.

If control and bus power are correct but amplifier remains offline, the drive has likely failed internally and requires replacement.

Check alarm history for preceding alarms (overload, overheat, overcurrent) that may have caused the amplifier to shut down before disconnecting.

Verify amplifier cooling fans are operating properly and heat sinks are clean. Check ambient temperature in cabinet - overheating can cause protective shutdown.

Swap the suspected amplifier with an identical known-good unit or swap with another axis amplifier to isolate hardware failure.

Ensure parameter settings match the axis before swapping drives, or reload parameters after swap.

If alarm follows the amplifier to new position, the drive is defective and must be replaced. If alarm stays with the axis, investigate motor or feedback device issues.