The Sony PlayStation 3 gaming console has three different connection types for connecting to TVs. The first and highest quality type is the HDMI connection, which is used to transmit up to a full HD 1080p signal. The second type is the component connection, which is used to transmit up to an HD 1080i signal. The third and lowest quality type is the composite connection, which transmits up to a 480p signal. The component and composite connections on the PS3 go through an AV port, so to switch from HDMI you need Sony's PS3 AV (component or composite) cable.
Reposition your PS3 in a spot where you can freely access its back connections panel, and then remove the HDMI cable from it and the back of your TV.
Connect the AV end of the PS3 AV cable (component or composite) to the "AV MULTI OUT" connector on the back of your PS3.
Insert the other end of the PS3 AV cable into your TV's component or composite input connection and turn on your PS3 and TV. Your PS3 has now been switched from the HDMI connection to AV; view the PS3 video signal on your TV by selecting the "Component" or "Composite" video input mode.