Whats wrong when plasma stays black but you can hear the sound?

the video feed isn't getting through (AV cable not inserted properly or faulty or incorrect cable being used). If the only cables going into the tv are the AC lead and the antenna cable the tv is faulty and needs a repairman the video feed isn't getting through (AV cable not inserted properly or faulty or incorrect cable being used). If the only cables going into the tv are the AC lead and the antenna cable the tv is faulty and needs a repairman