Code SP0134: Soft phase alarm
Issue Description & Safety Warning
The Fanuc Alpha-i Servo Spindle Amplifier has triggered a critical Soft phase alarm alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
Amplifier LED display: d4 Also shown as: SP0134 (15i), SP9134 (30i/31i/32i), SP9134 (0i-D) Cause: A change to position data from the sensor (serial) was detected exceeding the expected range. When this alarm is issued at the start, possible causes are both (a) and (b) below. When the machine has been operating normally, the possible cause is (b). Troubleshooting when this alarm is issued (a) There is a parameter setting error. Refer to the section, "Parameters Related to Start-up," in the FANUC AC SPINDLE MOTOR αi series Parameter Manual (B-65280EN) to check the settings of the sensor setting parameters. (b) Check the shielding of the cable between the sensor (serial) and Spindle Amplifier. Check the items related to the section, "Detectors," in the FANUC SERVO AMPLIFIER αi series Descriptions (B-65282EN).
Source: Fanuc αi Servo/Spindle Amplifier Maintenance Manual (B-65285EN/04) — Part II Troubleshooting
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Fanuc Alpha-i Servo Spindle Amplifier Alarms
Fanuc controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code SP0134 on the Alpha-i Servo Spindle Amplifier identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Fanuc's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 135 Fanuc Alpha-i Servo Spindle Amplifier codes.
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