It did not work for a very long time for me.. finally if I did not insert fully and if the TV part is plugged in first it works. I think for many the cable connector is loose or is not oriented properly such that a stable connection is made when fully inserted..

Last page of this thread might be of use

http://talk.maemo.org/showthread.php?t=67868

Not the best solution but you could buy a 4 pole 3.5mm jack cable, cut it down and attach a 75 ohm resistor to the signal cable for video and to ground. Then plug this in just to enable tv out and swap for your normal cable.

Could also make a new cable with a switch built in to go to a 75 ohm resistor. The flick this on and off to enable tvout

Please, could someone tell me how can i debug tv output ? I'm facing problems with video. The audio is played ok on a sony bravia TV but no video at all. Is there any log that i can catch to see if the problem is either hardware or software related ?
Thanks in advance.

edit: Solved. The problem is with a cheap input selector. Sorry for ask before test all possibilities.