The Fanuc 0i-Model A (0i-A) is the first-generation 0i controller. Like other early controllers it shows alarms as plain numeric codes (no letter prefix). Below are the alarms technicians meet most often, with causes and fixes.
How 0i-A Alarm Numbers Map
- 000–199 — Program / parameter alarms
- 300s — APC (encoder) • 400s — Servo
- 500s — Overtravel • 700s — Overheat / spindle • 900+ — System
Common 0i-A Alarms
| Alarm | Meaning | Common Cause & Fix |
|---|---|---|
| 000 | Please turn off power | A parameter requiring a power cycle was set. Turn OFF then ON. |
| 100 | Parameter write enable | PWE = 1 on the SETTING screen. Set PWE = 0 and RESET. |
| 300 | APC alarm — reference return required | ABS position lost (battery change). Perform zero-return. |
| 401 | Servo amplifier VRDY (ready) OFF | Amp not ready — check DC link, E-stop, amp power and fault LED; repair/replace drive. |
| 404 | VRDY signal ON (stuck) | Faulty servo amplifier or wiring. |
| 410 / 411 | Excessive position error (stop / move) | Bind, overload, encoder or amplifier/motor fault. |
| 414 | Digital servo system fault | Check the amplifier alarm code, motor and feedback. |
| 417 | Illegal digital servo parameter | Restore parameters; replace CNC battery A98L-0031-0025. |
| 500 / 501 | Stored stroke limit + / − exceeded | Jog back inside range and reset. |
| 700 | Overheat: control unit | Check cabinet/control cooling fan and ambient temperature. |
| 704 | Spindle speed fluctuation / overheat | Overload, belt slip, motor or spindle amplifier fault. |
Need the Part — or a Repair?
JJ Automation stocks new and tested used/refurbished Fanuc 0i-A spares — 100% checked before dispatch — plus board-level repair.
- 🛒 Browse Fanuc 0i-A parts, servo drives and PCB boards
- 📞 Call / WhatsApp: +91 8802212394 ✉ jj.automation@outlook.com 🌐 www.jjautomation.in
Quick-reference of common alarms. For the complete list, refer to the Fanuc 0i-A Maintenance Manual.