Do you have the audio set to external speakers?
I was under the impression that the audio out for the television was an RCA cable, so you'd need an RCA-to-3.5mm(male) to send the audio from the television. (At least, the U.S. models are designed that way). Can you clarify where you plugged in the 3.5mm cable?
My tv (<1 year old) has a problem with its sound. I used a cable with a 3,5mm plug to wire the sound from Ipod, computer and also my tv to my amplifier but suddendly that doesn't work with my tv anymore. It works with computer/Ipod so I know it's not the cable. Also I DO have sound coming from my tv (but that is not great quality).
Anybody had this problem or knows what to do? Thanks in advance