Ok so I'm using hdmi and sometimes when I go on games it goes to a black screen and the sound still plays but no picture it's a new hard drive as well I'm so close to getting an Xbox again it's really annoying
Turn off the PS3 and then press and hold the power button on the front until the PS3 beeps a second time. This resets the display settings, and should sort your problem. You'll need to go to display settings and auto detect.
If the TV only supports 720p, then 1080i and p won't work and will result in a black screen.