I have a Sony hx853 40" tv, couple of years old, but the last few days I've been experiencing these periodic blackouts where the screen goes black, but the audio continues. These episodes usually last a split second to a couple of seconds. 

Signal quality/strength are high, 100/97, and doesn't happen on hdmi feeds such as blu-rays. It doesn't happen that often, but I'm at a loss as to the cause.

Edit: should add, tv is on the latest firmware that has been fine for 9 mnths or so