HAAS® Alarm 105 — Z SERVO ERROR TOO LARGE
Part of: our HAAS® alarm reference · covering 60 of the most common alarms.
What it means
Following error on the Z axis. Z is the most common axis for this alarm because it carries the spindle weight and takes the worst of any crash.
Common causes
- Z counterbalance pressure low (mills) — the air or hydraulic counterbalance helps support the spindle weight
- Crash damage to the Z ballscrew or guides
- Way lube starvation on the Z column
- Encoder cable fault
What to check first
- Check air pressure (mills with pneumatic counterbalance need ~85–100 psi)
- Move Z by hand — it should feel smooth, not heavy or notchy
- Inspect the way lube system and check the lube reservoir
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.