FANUC Alarm SRVO-251 — DB relay abnormal
Error- Hardware
- servo amplifier
- Controllers
- R-30iA / R-30iB
- FANUC class
- SERVO
Manufacturer wording — DB relay abnormal(G:%d A:%d)
The manual prints placeholders; your controller fills them in with the real group, axis or number.
FANUC SRVO-251 (“DB relay abnormal”): The dynamic brake relay in the amplifier is abnormal. First check: Replace the amplifier. Likely part: Servo amplifier (Servo amplifier).
Updated 2026-10-22 · LogrobotLM reference
Description
The dynamic brake relay in the amplifier is abnormal.
Remedy
Replace the amplifier.
Field diagnosis
The internal dynamic brake relay of the amplifier is faulty.
What to check
- Replace the amplifier; on R-30iB, the emergency stop unit second.
- Note: No on-site repair possible.
Part to check / replace
FANUC SRVO-251 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 →