Why does my hdmi cable only work sometimes on ps3?

Like the first guy said always make sure your system is in a cool spot for it to vent and stays clean. But, have you tried it without the AV cables? I only use the HDMI cable hooked up, maybe if you leave the display settings to adjust automatically and only have that cable in use it will just lower the graphics quality but keep using the cable.

Well, standard AV cables would mean the PS3 will output at standard definition, not HD like the HDMI. HD requiring more work of the graphics card than standard definition. So, this extra work, causes the interals to get hotter. It gets to a point, and it'll freeze up. So, my solution, clean your PS3, make sure it doesn't have dust inside. Place the PS3 in an open, somewhat ventilated area, and try to keep that area clean from dust. Finally, lower the thermostat a little, bring down the overall temperature of the room. You could probably verify this by having HDMI output, but lower the video settings to 480p. If the PS3 doesn't shut off while running at 480p, that's the cause. If not . . . well, I don't know, that's the only logical explanation I can come up with.

Well, standard AV cables would mean the PS3 will output at standard definition, not HD like the HDMI. HD requiring more work of the graphics card than standard definition. So, this extra work, causes the interals to get hotter. It gets to a point, and it'll freeze up. So, my solution, clean your PS3, make sure it doesn't have dust inside. Place the PS3 in an open, somewhat ventilated area, and try to keep that area clean from dust. Finally, lower the thermostat a little, bring down the overall temperature of the room. You could probably verify this by having HDMI output, but lower the video settings to 480p. If the PS3 doesn't shut off while running at 480p, that's the cause. If not . . . well, I don't know, that's the only logical explanation I can come up with.