Blank screen on HDMI connected PS3

[CptGreedle]

The PS3 should be set up to use HDMI, as well as the tv. Make sure it is looking at the right source now that it using HDMI and not composite.
Also, assuming the HDMI cable is not faulty/broken, it could be the port on the TV or AV receiver. See if you can use a different port. My sister had this happen to her computer, we spent months trying to fix the graphics card only to find out the monitor had a bad port.
Finally, HDMI is very picky. I often had certain cable channels go out on me for no reason and come back on when I change the channel. This is due to 2 things, the HDMI cable, and Hi def copy protection.
The HDMI cable will be very likely to go out if it is moved or not in place just right. Some cables probably are better than others at this, but it has been known to happen. Also, some hi def signals use a copy protection that will turn off the signal if it thinks it detects any recording device. It is easily fooled and will turn off the signal if the HDMI cord is not in "just right".
I am not sure this helps at all, but these are a few of the things I could think of.

Make sure the cord is good, make sure the port is good, make sure the tv is set right, make sure the PS3 is set right, make sure the cables are in properly.