HAAS® Alarm 106 — A SERVO ERROR TOO LARGE
Part of: our HAAS® alarm reference · covering 60 of the most common alarms.
What it means
Following error on the A axis (4th axis rotary, indexer or trunnion). The A motor is failing to track its commanded position.
Common causes
- Worm gear preload too tight or worn
- Brake not fully releasing before the move
- Encoder cable fault on the rotary
- Aggressive feed on a heavy fixture
What to check first
- Check that the rotary brake releases properly — listen for the air or hydraulic release
- Inspect the rotary's encoder/feedback cable
- Reduce feed and try a small index move
Prevention
Following errors are often a slow-creeping problem before they become an alarm. Keep an eye on the axis load meters during normal production — if one axis is consistently working harder than it used to, get it looked at before it trips. Way cover seal replacement and ballscrew lubrication are the cheapest insurance you can buy.
If you’re still stuck
If you’ve worked through the checks above and the alarm hasn’t cleared — or if it cleared and came back — that’s the point to call. Persistent alarms after a reset usually mean a real component fault, and pushing through them risks turning a simple repair into a bigger one. Keith covers HAAS® breakdowns across the UK with same-day phone diagnosis.
A note on this guide. Alarm wording and numbering can vary by HAAS® machine model and software revision. The descriptions here are written in plain English to help you understand what the machine is reporting and what to check first — they’re not a substitute for the official HAAS® operator manual or for a qualified service engineer’s diagnosis. Always confirm the exact alarm message on your screen and consult your machine’s documentation before attempting any repair.