That is rather odd. The only thing I can think of is to change
/boot/config.txt
sdtv_mode=1
to
sdtv_mode=0
From here:
http://raspberrypi.stackexchange.com/questions/23915/the-composite-video-on-my-raspberry-pi-isnt-working
Otherwise, short of a fresh SD image install I’m not sure how to fix it.
