What the SRVO-075 alarm means

The pulse coder position changed while the controller was powered off, so the stored position no longer matches the actual mechanical position. This is one of the faults our repair team handles most often — the cause is usually identifiable within the first on-site inspection.

Most common causes

  • Axis moved by external force while power was off (brake released, manual push)
  • Backup battery failed and data was partially lost
  • Motor or pulse coder replaced
Field note: the first item on this list is what we find most often on real machines. Check it before you go deeper.

Step-by-step field fix

  1. Do NOT run production - the robot may move to wrong positions
  2. Set $MASTER_ENB = 1, press RES_1PA, cycle power
  3. Re-master the affected axis (zero mastering or quick mastering)
  4. Verify with a known reference point or fixture before releasing to production
Safety first: never bypass safety circuits or force contactors closed. If the alarm involves E-stop chains or servo power, and you are not a trained robot technician, contact a professional — wrong moves here can cost you a robot or an injury.

Still stuck? Get an engineer on the phone — right now

Tell us the alarm code, the robot model and what was happening when the alarm came up. Our engineers run these diagnostics every day, and remote diagnosis by phone or video call is free.

Get a Free Remote Diagnosis See Repair Services

Hotline: +86-20-39029800 · WhatsApp: +86-188-1886-2860

Related Battery & Mastering alarms

SRVO-062 — BZAL Alarm (Group / Axis) SRVO-065 — BLAL Alarm - Battery Voltage Low SRVO-027 — Robot Not Mastered SRVO-038 — Pulse Mismatch (Group / Axis)
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-075 alarm mean?

The pulse coder position changed while the controller was powered off, so the stored position no longer matches the actual mechanical position. In field practice it belongs to the battery & mastering family of faults.

QCan I clear a FANUC SRVO-075 alarm myself?

Sometimes. Follow the step-by-step checks on this page — start with the first cause listed, which is what we find most often in the field. If the alarm returns after two attempts, or the fault involves power/safety circuits, stop and call a qualified robot service engineer.

QHow fast can a Henghuan engineer help?

On-site response in the Pearl River Delta within 30 minutes to 3 hours, across mainland China in 1–3 business days, and worldwide within 2–5 business days. Remote diagnosis by phone/WhatsApp/video is available immediately.

Written by the Henghuan Robotics repair team from field service experience. Alarm descriptions are our own summary for troubleshooting reference and may vary by controller version — when in doubt, check your FANUC documentation or contact us. Henghuan is an independent service provider, not affiliated with or endorsed by FANUC.