0855

Common Causes

• Loose or damaged converter link cable or connector between the power unit and inverter unit
• Faulty power unit
• Faulty inverter unit control board
• Electrical noise or an interrupted link causing a time-out

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code X=0 = Communication error on the converter link; YY shows the communication status at detection; code X=1 = Time-out error — communication was interrupted; YY is always 0
2. 2Read the code: if the leading digit X is 0 it is a communication error; if X is 1 it is a time-out meaning communication was interrupted (YY then is always 0).
3. 3Lock out main power and allow the DC bus to discharge before touching drive hardware, then reseat and inspect the converter link cables and connectors between the power unit and inverter unit for bent pins, corrosion, or damage.
4. 4Check cable routing for chafing or proximity to high-noise sources that could interrupt the link.
5. 5If cables and connectors are good, suspect the power unit next; swap or test it per your service procedure.
6. 6If the power unit checks out, the inverter unit control board is the remaining suspect — replace or have it tested.
7. 7If the alarm persists after these checks, record the alarm number, code and object and contact Okuma service.