Magnum Delta Force USB Issue

Hi everyone,
This is the anomaly that occurs on my Magnum Delta Force:
In AM and FM and LSB everything works correctly, when I switch to USB the s-meter rises almost to full scale and the radio becomes silent. If I turn off the radio switched to usb mode and after some time i turn on it works normally until I press the button to switch again into USB mode and the radio shows again the defect becomes silent.

Has anyone ever encountered the same problem?

Thank you