Applicable Systems
AC500
AC590
ACS580
ACS880
Symptoms
MCB (motor control board) control fault detected.
Possible Causes
- MCB hardware failure
- MCB firmware corruption
- Internal communication to MCB lost
Troubleshooting Steps
- Step 1: Power cycle the drive
Fault may clear if transient - Step 2: Check MCB diagnostic LEDs
LEDs show normal status pattern - Step 3: Replace MCB if fault persists
New board initializes without fault
How to Reset
Reset via control panel or power cycle after repair.
Source: ABB ACS580 Firmware Manual
Category: PLC & VFD