The DX-440 is a ruggedly built electronic unit with all parts conservatively rated. You will find it will give you long life enjoyment if kept free from excessive humidity. Weak microprocessor or radio batteries. Microprocessor fails to intialize. This may happen when you first install batteries.
Display is dim Weak microprocessor or radio batteries.
Headphone jack is plugged in. DC power cord is not correctly inserted into cigarette lighter socket in vehicle operation. AC jack or external DC jack is plugged in when trying to operate on batteries. Weak or intermittent sound Weak radio batteries Antenna adjustment insufficient. Try moving the unit near a window when operating in a vehicle or in a metal frame building.