I have a 4 channel Techview DVR. It has worked fine for over one year but recently was unplugged for sometime and when I switched it on again all I see where the 4 video images should appear on the monitor is the words "Video Loss". I had assumed that as long as the input cables are connected then the images should appear without configuration. Is this so ? , if not can someone please guide me how to get the live view to appear. Thank you in advance. Gerry