Video flickering continuously/ going blank for a fraction of second..

[nulll]

Hello,
The video on screen is flickering continuously - screen goes blank for a fraction of a second and video is back.. happens every few seconds.. happening across channels, so not really a signal issue.

Any idea what is the reason? STB going bad?? Or is there some issue?

 

[82krishnakumar]

Which box .? may be box issue