Philips Magnavox older model TV won't come on, makes clicking noise?

TV was on and working fine. I left the room and when I came back the screen was black and the only sound was a clicking noise. LED power light was not on. I have tried unplugging the set and resetting the cable box and pressing the On/Off button....nothing makes any difference. Still no picture or sound...except the clicking noise. Any suggestions of the possible problem and repair cost?