Abstract: Method and apparatus for testing the video subsystem of a PC in a manufacturing environment. Hsync and Vsync signals from a VGA connector of the PC are input to first and second trigger inputs, respectively, of a monostable multivibrator (“MM”) of the test device to drive respective outputs thereof. In particular, the presence of Hsync at the first trigger input triggers the MM to output a positive pulse at a first output thereof; similarly, the presence of Vsync at the second trigger input triggers the MM to output a positive pulse at a second output thereof. Each of the first and second outputs is used to drive an LED, such that the presence of Hsync and/or Vsync results in the illumination of a corresponding LED.