FANUC Alarm SRVO-074 — SERVO LDAL alarm
Error- Hardware
- Pulsecoder (encoder)
- Controllers
- R-J3iB / R-30iA / R-30iB
- FANUC class
- SERVO2
- Hardware family
- FANUC Pulsecoder, backup battery and position loss alarms
Manufacturer wording — SERVO LDAL alarm(Group:%d Axis:%d)
The manual prints placeholders; your controller fills them in with the real group, axis or number.
FANUC SRVO-074 (“SERVO LDAL alarm”): The LED on the pulse coder has become disconnected. First check: Replace the pulse coder, then master the robot. Likely part: Pulsecoder (Pulsecoder (motor encoder)).
Updated 2026-10-22 · LogrobotLM reference
Description
The LED on the pulse coder has become disconnected.
Remedy
Replace the pulse coder, then master the robot.
Field diagnosis
The LED that illuminates the Pulsecoder optical disk has failed.
What to check
- Replace the Pulsecoder, then redo the mastering.
- Note: Irreversible fault; no procedure clears it.
Part to check / replace
FANUC SRVO-074 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 →