First, check whether the power supply of the surveillance camera is out of the question, if it is an infrared surveillance camera, you can see the red light at night, it means that the power supply is normal; if not, you can use a multimeter on the power supply and power supply lines to measure.
Second, check the line is not a problem, if the line is not a problem, it may be a bad camera, you can replace the alternative method of detection, with a good camera to replace the test, if there is an image that the camera is bad.
Third, look at the video terminal is not a problem, because the video equipment is not set up or with the wrong phenomenon will also appear black screen.
Fourth, the monitoring of the video signal line broken (including line damage, poor contact connector), also can cause a black screen.
Fifth, the monitoring camera control equipment, such as DVR/NVR/capture card, etc., to check whether the relevant software is running normally, whether it is the latest version, if not, it is recommended to contact the manufacturer for software upgrades.