I jus reseted my playstation 3 and still didnt work, i get sound but no video. my standard a/v cables do not work, but the universal a/v cables come in black and white

should be an 'input' button or some variation of the name on the remote.
or
Copied directly from the Sony website:

Perform the following steps to reset the Video Output Settings.

Make sure the HDMI cable is connected to the [HDMI OUT] port on the back of the PLAYSTATION 3 system.

Connect the other end of the HDMI cable into the [HDMI Input] port of the TV or display monitor.

While the PLAYSTATION 3 system is in standby mode (red light on the front of the system), hold down the touch-sensitive On/Off button on the front of the system until the system goes into standby mode again . (So the light cycle would go from: red light to --> green light --> then back to red light) This will ensure that you have held down the On/Off button long enough to reset the Video Output Settings.

Turn ON the PLAYSTATION 3 and once the system finishes powering up, the Video Output Settings will automatically reset to the standard resolution (or detect the current display output settings of your TV/monitor).
If resetting does not auto-detect your HDTV, see next step below.

It is probably due to the fact that your PS3 needs resetting back to standard definition. Try holding the power button down for 5 seconds until it beeps. It should then revert back to standard.

Hope this helps

1. Make sure the HDMI cable is connected to the HDMI OUT port on the back of the PLAYSTATION 3 system. Connect the other end of the HDMI cable into the HDMI Input port of the TV or display monitor.
   
2. While the PLAYSTATION 3 system is in standby mode (red light on the front of the system), hold down the touch-sensitive power button on the front of the system until the system goes into standby mode again . (So the light cycle would go from: red light --> green light --> then back to red light). This will ensure that you have held down the power button long enough to reset the Video Output Settings.
   
3. Turn on the PLAYSTATION 3 system and once the system finishes powering up, the Video Output Settings will automatically reset to the standard resolution (or detect the current display output settings of your TV/monitor).......
   

1. Make sure the HDMI cable is connected to the HDMI OUT port on the back of the PLAYSTATION 3 system. Connect the other end of the HDMI cable into the HDMI Input port of the TV or display monitor.
   
2. While the PLAYSTATION 3 system is in standby mode (red light on the front of the system), hold down the touch-sensitive power button on the front of the system until the system goes into standby mode again . (So the light cycle would go from: red light --> green light --> then back to red light). This will ensure that you have held down the power button long enough to reset the Video Output Settings.
   
3. Turn on the PLAYSTATION 3 system and once the system finishes powering up, the Video Output Settings will automatically reset to the standard resolution (or detect the current display output settings of your TV/monitor).

1. Make sure the HDMI cable is connected to the HDMI OUT port on the back of the PLAYSTATION 3 system. Connect the other end of the HDMI cable into the HDMI Input port of the TV or display monitor.
   
2. While the PLAYSTATION 3 system is in standby mode (red light on the front of the system), hold down the touch-sensitive power button on the front of the system until the system goes into standby mode again . (So the light cycle would go from: red light --> green light --> then back to red light). This will ensure that you have held down the power button long enough to reset the Video Output Settings.
   
3. Turn on the PLAYSTATION 3 system and once the system finishes powering up, the Video Output Settings will automatically reset to the standard resolution (or detect the current display output settings of your TV/monitor).

try resetting the display settings u can hold the power button for 2 beeps and the settings will be reset to the standard settings. make sure that your using the correct cables and that your tv is on the correct input. i reccomend using an HDMI cable its a universal cable and it works world wide!

jus keep checking the cables in the back of the tv and if they are in correct it could jus be the video cable is being dodgy lol

If you originally set up the PS3 with A,V cables it won't work on HDMI even if you set it up to and visa versa. There is a work around but you will have to call tech support. Here is a link at Sony's PS3 tech support that may help also. http://playstation.custhelp.com/cgi-bin/playstation.cfg/php/enduser/std_adp.php?p_faqid=263

does your ps3 power up but no video?

Have you tried doing a video check and reset with the standard def cable that came with the PS3?

All: Try this -

Perform the following steps to reset the Video Output Settings.

1. Make sure the HDMI cable is connected to the [HDMI OUT] port on the back of the PLAYSTATION 3 system. Connect the other end of the HDMI cable into the [HDMI Input] port of the TV or display monitor.
   
2. While the PLAYSTATION 3 system is in standby mode (red light on the front of the system), hold down the touch-sensitive On/Off button on the front of the system until the system goes into standby mode again . (So the light cycle would go from: red light to --> green light --> then back to red light) This will ensure that you have held down the On/Off button long enough to reset the Video Output Settings.
   
3. Turn ON the PLAYSTATION 3 and once the system finishes powering up, the Video Output Settings will automatically reset to the standard resolution (or detect the current display output settings of your TV/monitor). [If resetting does not auto-detect your HDTV, see next step below.]

NOTE: As of system software update version 1.60, the PLAYSTATION 3can automatically detect an HDMI connection to a TV. If the PLAYSTATION 3 is turned on with an HDMI cable connected, the screen for switching video output settings will be displayed automatically. (Does not function unless the TV that is connected by the HDMI cable is turned on.)

As of version 1.80 of the system update for the PLAYSTATION 3, the PLAYSTATION 3 can upscale the video content of PlayStation® format software, PlayStation®2 format software, and DVDs to HD resolution.
If Resetting the Video Output Setting Did NOT Detect Your HDTV Automatically (Certain TV's Only)
With certain televisions, the PLAYSTATION 3 may not automatically detect the HDMI source (TV) which it is plugged into, even after resetting the Video Output Setting (as described above).

If resetting the Video Output Setting did not work, you may need to follow these steps to manually locate the HDMI source:

1. Connect both the AV Cable and the HDMI cable from the PLAYSTATION 3 to the corresponding (AV and HDMI) ports on your TV. 2. Proceed with resetting the Video Output Setting on the PLAYSTATION 3 again. (Follow these steps, then continue to step 3 below.)
3. Turn the TV channel to the corresponding "Input" or "Video" channel for the AV Cable connection.
4. Manually change the Video Output Settings to HDMI. (Follow these steps, then continue to step 5 below.)
5. Now switch the "Input" or "Video" channel on the TV for the HDMI port the PLAYSTATION 3 is currently plugged into.
6. Accept the display settings for HDMI before the timer runs out (30 seconds). Highlight "Yes" and press the X button.
7. You can now disconnect AV Cable from the PLAYSTATION 3 and the TV, as it is no longer needed.

With certain televisions, the PLAYSTATION 3 may not automatically detect the HDMI source (TV) which it is plugged into, even after resetting the Video Output Setting (as described above).

If resetting the Video Output Setting did not work, you may need to follow these steps to manually locate the HDMI source:

1. Connect both the AV Cable and the HDMI cable from the PLAYSTATION 3 to the corresponding (AV and HDMI) ports on your TV. 2. Proceed with resetting the Video Output Setting on the PLAYSTATION 3 again. (Follow these steps, then continue to step 3 below.)
3. Turn the TV channel to the corresponding "Input" or "Video" channel for the AV Cable connection.
4. Manually change the Video Output Settings to HDMI. (Follow these steps, then continue to step 5 below.)
5. Now switch the "Input" or "Video" channel on the TV for the HDMI port the PLAYSTATION 3 is currently plugged into.
6. Accept the display settings for HDMI before the timer runs out (30 seconds). Highlight "Yes" and press the X button.
7. You can now disconnect AV Cable from the PLAYSTATION 3 and the TV, as it is no longer needed.