Concord DVR: all my cameras have no signal

Symptoms of this issue: The cameras displayed on the screen connected to a Concord DVR (Model name CDKxxxx-x) all say "Signal Lost" as shown below.

Cause: The cameras have lost power. The power pack that supplies the cameras is switched off, unplugged from the mains, damaged, or the splitter cable from the plugpack to the cameras is unplugged.

Solution: Look behind the system for the two mains power bricks or plugpacks plugged into it, and trace their cables. One plugpack will be connected to the DVR box itself - you can ignore this one.

The other plugpack will be connected to a 1-to-4 splitter cable that connects to red plugs on the ends of the white cables coming from the cameras. 

The camera plugpack needs to be checked to make sure it is plugged in, switched-on, and is supplying power to the cameras.

You can use a multimeter set to DC 20v range to test the plug output of the plugpack - it should be approximately 12v. If the plugpack is not supplying power, try another power point or power board (reset the power board if it has a reset button), and if no better, visit a store to buy a replacement, such as MP3316 or MP3490.