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FANUC Alarm SRVO-239 — SERVO Chain 2 (SVON) abnormal

FANUC SRVO-239 (“SERVO Chain 2 (SVON) abnormal”): A single chain 2 (0V) failure occurred when a SVON (Servo ON/OFF switch) input was asserted. First check: Repair the circuit of the chain 2 (0V) on SVON the hardware.

Updated 2026-09-17 · LogrobotLM reference

Description

A single chain 2 (0V) failure occurred when a SVON (Servo ON/OFF switch) input was asserted.

Remedy

Repair the circuit of the chain 2 (0V) on SVON the hardware. Set CHAIN FAILURE detection to TRUE on the SYSTEM/CONFIG screen. Press RESET on the teach pendant.

Related codes

SRVO-237WARN Cannot reset chain failureSRVO-238SERVO Chain 1 (SVON) abnormalSRVO-240SERVO Chain 1 (FENCE) abnormalSRVO-241SERVO Chain 2 (FENCE) abnormal

Indicative field information — the robot manufacturer's manual and safety procedures always prevail. Never bypass a safety device; apply lockout/tagout (LOTO) before any physical intervention. How this reference is built →