TV is making a rat a tat tat sound

[GramBerna]

Not really Home Theatre, just my TV .
My Toshiba TV has started making a loud knocking or rat a tat tat sound - it is loud and I have to turn the volume up on the TV to hear over it!~ What could be going out? I have it hooked up to ATT+T Uverse with a DVR but the other TVs in the house go through the same box and I don't have this problem with them. What can I do?

 

[MiDNiGHTsoul]

The speakers could be messed up if the tv is old. Try disconnecting some of the stuff that are hooked on the tv.

or maybe a wild rattata got into the tv.