Sometimes after using your PS3 in HDMI mode you may not be able to connect it to another TV set, using the Scart mode (Not detected). In this instance, you will probably want to reset the console to ...
I tried swapping HDMI ports on the TV, turning the TV on long before the PS3, holding down power for ~5 seconds until it gives the single beep indicating a video setting reset, and swapping HDMI ...