On Feb 1, 7:47*pm, David Nebenzahl wrote:

But every so often the program I'm watching blinks. Every few seconds
the picture blinks black. No corresponding breaks in the audio.

Bad reception is NOT indicated; that would cause the audio to
drop out, and the screen would freeze, not go black.

Two possibilities: your picture circuitry (possibly a video driver
power
supply) has a loose connection, or the TV station is having 'video
difficulties'.
If the TV is a LCD type, the backlight could be going out
intermittently,
if it's a CRT set, the HV might be arcing (this will usually cause the
screen picture size to change a bit also).

Can you record some black-ing video and see if it has the same
artifact on playback?