LogrobotLM

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FANUC Alarm SRVO-042 — SERVO MCAL alarm(Group:%d Axis:%d)

FANUC SRVO-042 (“SERVO MCAL alarm(Group:%d Axis:%d)”): 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 2026-08-29 · LogrobotLM reference

Description

The servo amplifier magnetic contactor (MCC) is welded closed. This is an S-900-specific alarm.

Remedy · Remède

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 · Pièce à contrôler / remplacer

FANUC SRVO-042 points to the hardware below — start here before ordering. · SRVO-042 met en cause l'organe ci-dessous : commencez par là.

Tap a part for every code that points to it — and verify the exact variant for your controller before ordering. · Touchez une pièce pour tous les codes qui la citent ; vérifiez la variante exacte avant commande.

Frequently asked · Questions fréquentes

What does FANUC alarm SRVO-042 mean?
FANUC SRVO-042 (“SERVO MCAL alarm(Group:%d Axis:%d)”): The servo amplifier magnetic contactor (MCC) is welded closed. This is an S-900-specific alarm.
How do you troubleshoot FANUC alarm SRVO-042?
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.
Which part is involved in FANUC SRVO-042?
SRVO-042 points to Servo amplifier (Servo amplifier). Confirm the real cause against the robot backup before replacing a part.

Related codes / Codes liés

SRVO-040WARN Mastered at mark pos(G:%d)SRVO-041SERVO MOFAL alarm (Grp:%d Ax:%d)SRVO-043SERVO DCAL alarm(Group:%d Axis:%d)SRVO-044SERVO HVAL alarm(Group:%d Axis:%d)

Same hardware involved / Même matériel en cause

SRVO-018Servo amplifierSRVO-021Servo amplifierSRVO-022Servo amplifierSRVO-023Servo amplifier

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. · Informations indicatives issues du terrain — le manuel du constructeur et ses procédures de sécurité font foi. Ne shuntez jamais un organe de sécurité ; consignez (LOTO) avant toute intervention physique. How this reference is built →