Screw air compressor frequency converter failure is a common mechanical failure, and troubleshooting requires professional knowledge and experience. Here are some common troubleshooting steps:

1. Check the power supply: First, make sure that the inverter has been connected to the correct power supply and that the voltage and current are within the specified range.

2. Check the circuit board: Check the inverter circuit board for moisture or other physical damage. If there is a problem, the circuit board needs to be replaced.

3. Check the motor: Check whether the motor has any abnormal sound or the temperature is too high. If there is a problem, the motor needs to be replaced.

4. Check the sensor: Check whether the sensor is damaged or set incorrectly. If there is a problem, the sensor needs to be replaced.

5. Check the controller: Check whether the controller is faulty or has wrong parameter settings. If there is a problem, the controller needs to be replaced or parameters reset.

6. Shutdown for maintenance: If the above steps cannot solve the problem, the machine needs to be shut down for maintenance. Before repairing, it is necessary to disconnect the inverter from the motor and ensure that the inverter stops running completely.

It should be noted that inverter troubleshooting requires professional knowledge and experience, so it is recommended to seek professional help. Safety codes and procedures must be followed before any repairs are made.