2155

Common Causes

• Loose, damaged, or disconnected converter link cable or connector
• Faulty power unit
• Faulty inverter unit control board
• Communication interrupted (time-out) from noise or a momentary break on the link

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 (YY is always 0 in this case)
2. 2Read the code: X=0 means a communication error, X=1 means a time-out where communication was interrupted; a time-out points more toward a broken connection or a unit that stopped responding.
3. 3Lock out the main power and allow the DC bus to discharge before touching drive hardware, then inspect the converter link cable between the power unit and inverter unit: reseat both connectors and check for pinched, burnt, or chafed cable.
4. 4Check connector pins for corrosion, coolant contamination, or backed-out contacts on both the power unit and inverter unit ends.
5. 5If the cable and connectors are good, the power unit is the next suspect; swap or test it per your service arrangement.
6. 6If the alarm still returns with a known-good cable and power unit, replace the inverter unit control board; record the full code and object before contacting Okuma service.