1. Directly connect the surveillance camera and the hard disk video recorder with a short-distance cable, and check whether the fault still exists. If there is no interference, check whether there is a strong current or a strong magnetic field near the line of the current surveillance camera with interference and replace the power supply of the surveillance camera with a new one;
2. Whether the display format of the surveillance camera and the video recorder is correct, such as PAL, etc.
3. Whether the wire impedance file of the surveillance camera is correct.
4. If there is a problem with the chip of the surveillance camera, return to the factory for repair.