3155

Common Causes

• Converter link cable damaged or connector loose/corroded
• Power unit faulty
• Inverter unit control board faulty

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code X=0 = Communication error on the converter link; code X=1 = Time-out error — communication was interrupted; code YY = Communication status value (always 0 when X=1)
2. 2Read the code on screen: X=0 indicates a communication error, X=1 a time-out meaning communication was interrupted entirely; YY shows the communication status (always 0 when X=1).
3. 3Before touching hardware, power down, lock out, and allow the DC bus to discharge — the power unit holds hazardous voltage after switch-off.
4. 4Inspect the converter link cables and connectors between the power unit and inverter unit: reseat both ends, check for pinched cable, bent pins, or oil contamination.
5. 5Swap or replace the converter link cable with a known-good one and retry — cabling is the most likely cause.
6. 6If the link cable is good, substitute or have the power unit checked, then the inverter unit control board, in that order.
7. 7If the alarm returns after these checks, record the alarm number, code, and object and contact Okuma service.