These flat screen LCD TVs have fluorescent lamps that are used to illuminated the screen. A problem with the supply to the backlight or the lamps themselves could cause a strobe effect. The other scenario is that the video itself is pulsating. In my opinion, the strobe effect is usually a product of a backlight issue. Depending on the version and model of your TV, the power supply may feed the backlights directly. If it does then I would try it first. If the backlight is separate or the supply does not fix it I would suspect a panel. That would make the repair non economical. Get a diagnosis from a TV tech who can see the TV and make checks if needed.