[Link: community.sony.com]

Post #4:
"The catch with Sony is that they use a 3 conductor jack on the TV IR input. If you use a 2 conductor, "mono" cable, the sleeve will short the sleeve and ring together and the IR input will not work. Switch to a "stereo", 3-conductor cable and it should work. You want sleeve to be ground, tip to be signal and no connection on the ring."