SP9056 (Alarm 56) Spindle Internal Cooling Fan fault in Fanuc drive

SP9056 (Alarm 56) Spindle Internal Cooling Fan fault in Fanuc drive

Description

SP9056 (Alarm 56) is specific to the Spindle Amplifier Module. While other fan alarms cover the radiator or PSM, Alarm 56 refers to the small internal cooling fan located inside the yellow plastic cassette of the spindle drive. This fan cools the control PCB and local logic chips. If this fan slows down (RPM sensing) or stops, the drive generates Alarm 56 to prevent the CPU from overheating and causing calculation errors.

Cause

• Dust Accumulation: The fan is buried deep inside the unit and often sucks in fine dust that bypasses filters.
• Bearing Seizure: The small sleeve bearings dry out after years of 24/7 service.
• Vibration: The connector on the PCB vibrates loose over time.

Solution

1. Locate Fan: This fan is often "hidden." You may need to squeeze plastic tabs on the front of the drive to slide out the fan cartridge.
2. Cleaning: Remove the fan and blow it out with air. Spin it by hand. If it feels gritty, cleaning is only a temporary fix.
3. Replacement: Replace with the specific Fanuc part number (often A90L-0001-0xxx). Note: Some drives require a parameter reset or power cycle to clear the latched alarm after fan replacement.