Report "I own a Proton TV Model No.VT290 I am trying to add two extra speakers. I plugged into the back at the audio "OUT" receptacles. No sound. I made sure the speaker switch is on. I checked the polarity of the wires.I placed the copper wire on the red terminal on back of speaker and attached to the center pole of the phono plug. There are other controls on the front of the TV.I'm not sure if I might have turned off a switch for these external speakers. Please advise"