Echogram is fixed and blue
The echogram displayed in Scala2 is completely blue. There is no yellow line moving on top of the echogram, which means that no sonar data is received.
![](../img/iconeFleche.png)
- From Mosa2, click and check that the frequency is between 120-210 kHz.
- If not, change the frequency.
![](../img/iconeFleche.png)
- Check that the name of the sensor on the top left corner of the echogram is Trawl Explorer.
- If not, from Trawl Explorer sensor data, click + hold Range of Sonar Data and drag it to the page.
![](../img/iconeFleche.png)
- Contact the support service for repair.