Probablemente será por que el puerto USB de la tele es UNICAMENTE para servicio
inputs and Outputs
AC Power Input : 1 (Rear) Pigtail
Analog Audio Input(s) (Total) : 3 (3 Rear)
Audio Out : 1(Rear)
Component Video (Y/Pb/Pr) Input(s) : 2 (Rear) (1 fixed/1 selectable)
Composite Video Input(s) : 1 (Rear selectable)
Digital Audio Output(s) : Optical Digital Output - 1 (Rear)
HDMI™ Connection(s) (Total) : 2 (Rear)
HDMI™ PC Input : Yes
PC In (D-Sub) + Audio In (Stereo Mini) : 1 (Rear) (see owner's manual for supported timings)
RF Connection Input(s) : 1 (Rear)
USB 2.0 : 1 (Rear for Service Only)