Ps3 2 monitor

are you swapping it from another display that has a higher resolution not supported by your monitor? if so make sure to change it to the native resolution of your monitor before unpluggin it from the other display.

If you're running your PS3 1080p and your monitor's maximum resolution is below that then you're not going to get a signal.

Change your PS3 output to 480p (or 576p if you're in a PAL area) then plug it into your monitor. You can then change the PS3's resolution to match the monitor.

Sounds like a resolution problem. 480p [640x480] should always work, regardless of moniter, so try that first.