What the SRVO-071 alarm means

The detected current speed of the motor is abnormally high - feedback data does not match reality, usually a feedback signal problem rather than real motion. This is a high-frequency ticket for our FANUC repair team, and on R-30iA / R-30iB / R-30iB Plus systems one inspection usually identifies the fault.

Most common causes

  • Noise on the pulse coder signal
  • Encoder cable damaged
  • Pulse coder failure
Field note: The top-listed cause has the highest hit rate, so checking it first narrows things down fast.

Step-by-step field fix

  1. Check encoder cable and connectors
  2. Improve grounding and cable routing away from noise sources
  3. If alarm follows the axis when motors are swapped, replace that pulse coder/motor
Safety first: For FANUC srvo-071, amplifiers and boards are live parts: hot-plugging a board burns interface circuits, and body static can kill sensitive devices. On site you may look at after confirming power-off the first step yourself: Check encoder cable and connectors. Beyond that it is live boards and power devices work - leave it to a professional.

How we diagnose amplifier/hardware alarms on site

FANUC srvo-071 belongs to the amplifier & hardware family. On FANUC srvo-071 the failing stage is alpha-i / beta-i servo amplifiers with PSM supply modules and SVM servo modules (SPM where spindles fit) on the R-30iB Plus / R-30iB Mate Plus / R-30iA - the amplifier and drive hardware itself plus its periphery: boards, fuses, cooling, supply, connectors and self-test. We start reading FANUC srvo-071 at the iPendant ALARM screen (SRVO / MOTN / SYST / INTF prefixes) together with the amplifier's 7-segment status code.

The chain involved in FANUC srvo-071 runs: control-side signal -> amplifier board (drive and sense circuits) -> fuses and supply -> cooling -> motor-side output.

Once FANUC srvo-071 is pinned to a board, there are two routes: Amplifier faults have two routes: replace the unit, or repair at board level. Replacement is fast and reliable but costly and lead-time bound; board-level repair (power modules, capacitors, reflow, drive-circuit fixes) can cost much less but needs test capability. We choose on two facts: is the fault point unambiguous, and how much downtime can the customer absorb? Clear fault and some patience means repair; line waiting or a fault inside a multilayer board means replace. Repaired boards go out only after a loaded test.

Field notes on this page cover FANUC srvo-071 (SPHAL - Soft Phase Alarm); written by the Henghuan repair team, updated 2026-10-01.

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Related Amplifier & Hardware alarms

SRVO-057 — FSSB Disconnect SRVO-068 — DTERR - Data Transmission Error SRVO-069 — CRCERR - CRC Error SRVO-072 — PMAL - Pulse Coder Phase Alarm SRVO-073 — CMAL - Pulse Coder Count Error SRVO-074 — LDAL - Pulse Coder LED Alarm
Same family: this code belongs to the Amplifier & hardware alarms family - the page collects all Amplifier & hardware-family codes we have handled, with the common inspection order and spares.
Other brands: see our KUKA, ABB, Yaskawa and Universal Robots field-fix libraries — or the full 10-brand hub.

Frequently asked questions

QWhat does the FANUC srvo-071 alarm mean?

The detected current speed of the motor is abnormally high - feedback data does not match reality, usually a feedback signal problem rather than real motion. This is a high-frequency ticket for our FANUC repair team, and on R-30iA / R-30iB / R-30iB Plus systems one inspection usually identifies the fault. FANUC srvo-071 sits in the amplifier & hardware family; on our work orders the highest-frequency trigger for this code is "Noise on the pulse coder signal".

QCan I clear a FANUC srvo-071 alarm myself?

Whether FANUC srvo-071 clears on its own depends on the outcome of "Check encoder cable and connectors". Finish the flow with "If alarm follows the axis when motors are swapped, replace that pulse coder/motor" to confirm FANUC srvo-071 - do not skip it. If that step is clean, the second most frequent cause on FANUC srvo-071 is "Encoder cable damaged". If FANUC srvo-071 returns after two clears, or the checks point at Noise on the pulse coder signal, stop the cell and call a professional robot repair engineer.

QFor hardware alarms like FANUC srvo-071, does it always mean an expensive part swap?

The commonest causes we see on FANUC srvo-071 are "Noise on the pulse coder signal, Encoder cable damaged, Pulse coder failure", so we stock the van against those. For FANUC srvo-071 specifically, we carry fuses, filter mats, common connectors and terminals; boards are stocked by type or go through the repair channel. For FANUC srvo-071, on hardware alarms we inspect before quoting - we do not open with replace the power stage. Before we roll, tell us what FANUC srvo-071 shows on the iPendant ALARM screen (SRVO / MOTN / SYST / INTF prefixes) together with the amplifier's 7-segment status code and what the machine was doing - phone or video triage is free.

This page on FANUC srvo-071 was compiled from actual repair records of the Henghuan Robotics repair team. Alarm notes are our own summary for troubleshooting reference only and may vary with controller and software version — please consult FANUC documentation or contact us if in doubt. Henghuan is an independent service provider, not affiliated with or endorsed by FANUC.