Vacon · X4
This fault indicates a problem with the control board temperature sensor (thermistor) or its connection. The drive cannot accurately monitor the control board temperature, which could lead to undetected overheating and damage to critical control components. This compromises the drive's ability to protect itself.
Click steps to track your progress.
1. Power down. Visually inspect the control board for any physical damage, burnt components, or loose ribbon cable connections.
2. Locate the control board thermistor (refer to drive manual for exact location) and verify its connections are secure.
3. Measure the ambient temperature immediately surrounding the control board using a calibrated thermometer.
4. If possible and safe, measure the resistance of the thermistor directly (requires knowing expected resistance values at room temperature). An open circuit or dead short indicates sensor failure.
5. Ensure all drive internal fans are operational and not obstructed, providing adequate airflow to the control board area.