Fanuc spindle alarm 88 means the spindle amplifier's heat sink cooling fan is not running — the external radiator fan that carries the power stage's heat out through the cabinet's rear duct has stopped. Fanuc's remedy is one line: replace the heat sink cooling fan. It completes the spindle amplifier's fan pair: AL-56 = the internal control-circuit fan; AL-88 = the heat-sink fan doing the heavy thermal lifting. Catching the fan stopped before the sink overheats is the point — ignore it and AL-09 (or worse) follows.
The fix — with the usual practical notes
- Confirm and inspect: open the rear duct and observe the fan. The duct-side fan is the dirtiest component on the machine — matted oil-dust is the usual killer. Power off before touching; a finger-spun fan that feels gritty has finished its bearings even if it still turns.
- Clean, then replace anyway: blowing it out may revive it temporarily, but a stalled fan has stressed windings — fit the replacement on your schedule, not the machine's.
- Genuine-spec fan only: the standing rule of this series — the amplifier monitors rotation via a sense wire; a generic two-wire fan reads as ‘stopped’ at full speed and the alarm never clears.
- Check the power feed: fan supply arrives via the amplifier/cabinet wiring — a fan that is genuinely unpowered points at the feed (connector, fuse) rather than the fan itself.
- If a genuine, powered fan doesn't clear it: the fan-sense input on the amplifier has failed — board-level repair.
Tip: The rear duct is shared — the PSM's and SVMs' radiator fans breathe the same dirt and are the same age. One dead duct fan means the whole row is due: clean the duct and inlet grille, and replace the fans as a planned set. Fans are the cheapest insurance in the cabinet; heat-soaked amplifiers are the most expensive consequence.
Related guides
- Fanuc spindle alarm 56 (control circuit fan)
- Fanuc spindle alarm 09 (heat sink overheat)
- Fanuc PSM alarm A (radiator fan)
AL-88 — or a whole duct of tired fans? JJ Automation stocks genuine-spec Fanuc fans for SPM/SVM/PSM units and repairs fan-sense circuits at component level. On-site fan-row replacement in NCR in one visit. WhatsApp us or call +91 88022 12394.