FANUC Alarm SRVO-042 — SERVO MCAL alarm
Manufacturer wording — SERVO MCAL alarm(Group:%d Axis:%d)
The manual prints placeholders; your controller fills them in with the real group, axis or number.
FANUC SRVO-042 (“SERVO MCAL alarm”): The servo amplifier magnetic contactor (MCC) is welded closed. First check: 1. If this alarm occurs with a SRVO-049 OHAL1, turn the power off for 15 seconds. Likely part: Servo amplifier (Servo amplifier).
Updated 2026-09-17 · LogrobotLM reference
Description
The servo amplifier magnetic contactor (MCC) is welded closed. This is an S-900-specific alarm.
Remedy
1. If this alarm occurs with a SRVO-049 OHAL1, turn the power off for 15 seconds. Then turn the power back on. 2. Check the cable between the servo amplifier and the axis control printed circuit board. 3. Replace the servo amplifier. 4. Replace the axis control printed circuit board.
Part to check / replace
FANUC SRVO-042 points to the hardware below — start here before ordering.
Tap a part for every code that points to it — and verify the exact variant for your controller before ordering.
Related codes
Same hardware involved
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 →