TL;DR
Alarm 108 on the Haas VF-2 means the Automatic Pallet Changer (APC) has reported an excessive fault. The fix is to acknowledge the alarm, power-cycle the machine, then inspect the APC proximity sensors and connector J10 for debris or loose pins.
What you might see
- alarm 108
- APC excessive fault
- pallet changer error
- haas alarm code 108
Likely causes
Debris obstructing APC proximity sensors
Loose or contaminated pins on connector J10
Misaligned proximity sensors after a crash
Required tools
- Lint-free cloth
- Phillips screwdriver
- Multimeter (optional)
Safety first
- Lockout-tagout the machine before opening the electrical enclosure.
- Allow the spindle to come to a complete stop before reaching into the work area.
Procedure
- 1
Press RESET on the control panel to acknowledge the alarm.[1]
Control Panel Layout Haas VF-2 control panel — RESET button highlighted
- RESET Button
- ALARM Display
- Mode Switch
- 2
Navigate to ALARMS > ACTIVE ALARMS to confirm the message reads 'Alarm 108: Excessive APC Fault'.[1]
- 3
Power cycle the machine: turn the main breaker OFF, wait 30 seconds, then turn it ON.
Warning: Lockout-tagout the machine before opening any electrical enclosure. - 4
If the alarm persists, check the APC proximity sensors for debris and clean with a lint-free cloth.[1]
- 5
Inspect connector J10 on the APC motor for loose or contaminated pins. Reseat if necessary.[1]
- 6
Run SETTINGS > DIAGNOSTICS > APC TEST to verify all sensor states report PASS.[1]
- 7
Press RESET once more and resume operation.
Sources
Haas VF Series Operator's Manual, Haas Automation Inc.
Section 7.4 - APC Fault Codes, page 218
View source“Alarm 108: Excessive APC Fault, see proximity sensor cleaning and connector J10 inspection procedure.”
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