Yep, check the device.
I tossed the brick (power supply) for my TV. It works great on ships 12VDC power. I also wired my laptop directly. That works too except my newer Sony was flickering at 12 volts. I wired in a transformer to raise its' supply to 19VDC. It still runs off of 12 volts, not 110AC. Now I'm still thinking about the Home Theater. It runs off of the inverter. It's designed for home use.P.S. As far as that TV not working anymore from the first post; the friend probably reversed the polarity. Most of these products aren't protected from mis-wiring because their bricks can't be hooked up wrong. A repair shop can fix it. (that's experience talking)(the first laptop, not the TV)