Sound but no picture

go to your manual selection botton on av source and select the rca input you plug the ps3

What is probably happening, is your PS3 is set for the wrong type of output. If you are using an HDMI cord, try switching to the AV cables that came with your PS3, and set your TV at the appropriate input to correspond with the AV hookups, and see if the picture works then.
If you are using the AV cables, it may have been set to HDMI accidentally. You need to use an HDMI cord, and hook the PS3 up to an HDMI compatible TV or monitor, and select the HDMI input. Once you get the picture working, go to Settings>Display Settings and set the display you wish to use.

is that the av channel? if so, how do you know your getting a signal from the ps3? try hooking the ps3 up to something else to make sure you have a signal coming out of that cable (this is where you have to start) if you have another device like a DVD player, or VCR, hook that up to the AV input (or channel one as you say). if you get a picture from those devices, the problem is your ps3 not sending the signals to the tv. sorry I can't be more helpful, but that's my guess

Be sure to check the cables. You may need to replace them.

Try the cables with another component, if possible.

Also, try using AV cables to verify that it is not the TV and to simply troubleshoot:

To get back to default AV settings:

Press and hold the power button until the systems shuts off. (wait 2 seconds)

Press and hold the power button again until it shuts off again.

Once you have verified that AV is working, turn off console, take out AV cables.

Plug in HDMI cable and turn system back on. Switch TV input to HDMI and it will ask you if you would like to use the HDMI cables, select yes again and verify.

If you cannot get sound, again, check the cables..

If new cables do not work, then your HDMI output is going bad, not from use rather normal wear and tear of the motherboard.

To get the best non HD picture, you will need to get some 'component' cables, rather than the standard AV (red, white, yellow).

Good luck

Look like ur Xbox 360 AV RCA cables is not making contact to the input board very well.Take some rubing achahol cleans the all those input holes,take the RCA AV connections make couples twises to the red,yellow and white,will help.Make contact with ur input board it should work.

Your display needs to be reset, Turn the ps3 off. Then turn the ps3 back on but continue to press the power button until you hear the beeps then it should work fine :)

make sure video cable is plugged in all the way on back of ps3. the a/v cable is little tricky. it looks like its plugged all the way but its not. also if doesnt work, if u have hdmi cable use it then go to display settings, then connetions. set it up as av cable connection then it will ask about audio - av rca connetions. and save. now its set up as av cables and then when u use hdmi it will automatically set up hdmi.

If you have set the component output on the ps3 for high def,ie 720p or 1080i and do not get a picture it sounds like the component input is not high def enabled on your amp,change the setting on ps3 to standard 576 output,or put picture into tv then sound into amp if you want to run 720p or 1080i.

Hope this helps.
CABLE GUY.

since you bought this console used, it maybe set to HDMI 1080p/ 1080i/720p output(by the original owner) and if your TV does not support this there will be no picture, the only way to lower the output resoloution is to get into the options menu but to do that you will need a freind with a tv that supports whatever resoloution its been set too.

I can't be exactly sure without more information, but it sounds like you ps3 is outputting from another port. My ps3 originally was outputting from the component/composite cable port so in order to use the hdmi output I had to do a soft reset. That makes the ps3 sense what cable is plugged into it and automatically output through that port instead of using whatever is the saved setting.

With your ps3 turned on hold down the power button for a few second until it beeps and flashes 3 times (should be about 5 seconds). You might have to try it a few times to get it to work, but you should get picture and be able to adjust the settings on the ps3.