1771

Common Causes

• Front door open/close confirmation limit switch out of position or faulty
• Ceiling door confirmation limit switch out of position or faulty
• Faulty door confirmation limit switch on a mechanical-locking type door
• Tailstock maintenance door, APC door, or operation door confirmation switch failure

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code None = Front door open/close confirmation limit switch failed (door interlock type S spec); code 1 = Ceiling door open/close confirmation limit switch failed (type S spec); code 3 = Front door open/close confirmation limit switch failed (mechanical locking type door); code 4 = Tailstock maintenance door confirmation limit switch failed (type S / flat machine spec); code 5 = Front door confirmation limit switch failed (type S / flat machine spec); code 6 = APC door open/close confirmation limit switch failed (type S spec); code 7 = Operation door open/close confirmation limit switch failed (type S spec)
2. 2Read the code to identify the failed switch: no code or 5 = front door (type S / flat machine spec); 1 = ceiling door; 3 = front door on mechanical-locking type; 4 = tailstock maintenance door; 6 = APC door; 7 = operation door.
3. 3Open and close the indicated door slowly while watching whether the limit switch actuator actually contacts and releases the switch plunger.
4. 4Check the switch mounting position — a switch that has slipped or a bent actuator bracket will not trip; readjust the switch position per the manual.
5. 5Inspect the switch wiring and connector for damage or coolant contamination.
6. 6Replace the faulty limit switch (for mechanical-locking doors, replace the open/close confirmation switch as the manual directs).
7. 7If a new, correctly positioned switch does not clear the alarm, record the alarm number and code and contact Okuma service.