The optical audio out "red light" comes on and prevents the Comcast cable box from powering on. Every time I try to turn on the cable box blinks four times, then the red optical audio out light comes on and shuts off the power light. I read in manual that this is an HDMI issue that can be resolved by choosing the proper option that will shut the red light off. But I cannot activate the menu/setup because the box does not show a picture on the screen. So nothing happens when I try to activate menu.