Ensure the Squelch is not turned too far to the right and that the Volume is up.
If you are looking for more specific information, I can help you with: Finding for your area. Instructions for cleaning battery corrosion in old units. Identifying the correct AC power adapter specs. Which of these would be most helpful for your scanner ? Netset Pro-44 Scanner Manual
This usually means you tried to enter a frequency that is outside the range of the Pro-44. Check your frequency list. Ensure the Squelch is not turned too far
Enter the starting frequency of the range you want to search. Press . Press LIMIT to set the upper frequency boundary. Press SEARCH to begin the hunt. Advanced Features Netset Pro-44 Scanner Manual