The SA300 series is known for a specific firmware bug—particularly in units manufactured around —that causes the screen to remain blank or show a "No Signal" message even when a cable is connected.
Updating to version 1.1.7 (or newer) is the standard software fix for these detection issues. download firmware samsung syncmaster sa300
Open the downloaded .exe file. It will typically install a small utility specifically for the update. The SA300 series is known for a specific