3734

Common Causes

• Failed limit or proximity switch used for ATC sequence checking, or a cut wire in its input signal circuit
• Failed hydraulic or air solenoid valve driving the ATC motion, or a cut wire in the solenoid signal circuit
• Fault in the hydraulic or air supply circuit powering the ATC
• Mechanical interference jamming an ATC mechanism mid-step

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code XXXXXXXX = On/off status of the limit switches for each ATC component at the moment the alarm occurred, used to identify which sequence step did not confirm.
2. 2Read the code shown with the alarm; it gives the on/off status of each ATC component's limit switch at the moment the sequence stalled, showing which confirmation never arrived.
3. 3Open the 'ATC CONDITION' screen (available in AUTO, MDI and MANUAL OPERATION modes); when the stall is caused by machine interference, this screen identifies the faulty sequence limit switch.
4. 4Check the indicated limit or proximity switch first: verify it actuates physically, then check its wiring for a cut or loose connection in the input circuit.
5. 5If the switch and wiring are good, check the hydraulic or air solenoid valve for that ATC motion: confirm it is being energized and that its signal wiring is intact.
6. 6Verify the hydraulic pressure or air supply to the ATC circuit is present and at proper level, and look for mechanical interference blocking the arm, magazine or changer mechanism.
7. 7If the faulty switch or circuit cannot be isolated, record the alarm number and code and contact Okuma service.