After learning this course, you can:

Know the common and typical product problems   and master their general solutions.

Be able to classify problems for the convenience of subsequent targeted analysis

Quickly locate problems through troubleshooting methods and solve problems on site.

Be able to conduct preliminary analysis and collect useful information when encountering difficulties

【System Topology 】

【HD CVI Transmission Cable and Distance】

For HDCVI system, please make sure the transmission distance between the CVI camera and the CVI DVR follows the standards as below.

In some projects, balun is adopted in the transmission for easy implementation.  For different baluns, please follow there own specifications(transmission distance) when deployed.

【POC unit】

PoC, referred to as Power over Coax, transmits both video and electrical power over a single coaxial cable. By eliminating separate camera power supplies, HDCVI PoC technology further simplifies HDCVI system deployment, therefore reducing time and cost.

400 m RG59 transmission. One channel can support 12W HDCVI camera with built-in PoC.

400 m OSD control.

12V to 36V DC wide voltage power supply.


Upgraded POC solution:

Supports 6W & 12W PoC camera access

Do not exceed 48W/96W for all channels


【Signal switch on HDCVI camera】

【Signal switch via menu】

You can also switch the output signal via OSD menu through HDCVI DVR.

【Signal switch via UTC control】

【VGA interface 】

【HDMI interface 】

HDMI transmission distance: within 10M

HDMI can transmit both video and audio signals. 

【Camera Fog Issue】

Problem description: 

The camera installed there and worked properly, but it has fog inside after some while. 

Possible reasons:

Air leakage or bad structures.

Desiccant invalid.


Check if the camera’s top cover has been opened before. 

Check it is installed properly. 

Air-tight test.

Check the desiccant is valid

Check the desiccant’s color is changed or not.

We can judge its usability from its color, for example, the color of C-1, C-2, H-1 and H-2 is orange which means the desiccant is valid. The color of C-3 and H-3 is changed to black which means the desiccant is already invalid. 

Generally speaking, the desiccant will become invalid when its moisture rate is above or around 14%.

The color of desiccant changed:  light orange(valid) → orange(valid) →green(invalid) →black(invalid

Go for RMA.

【No signal on live view menu】

Problem description:

At the local live screen of CVI DVR, the channel of the connected CVI camera is no signal, black screen. 

Possible reasons:

Unmatched formats between the CVI DVR and camera (P or N)

Camera end is nor working

–Camera power is off or loose connection

–Camera fault 


–Check if the related CVI channel is disabled. Then the CVI DVR will not detect any signal ,not even the live image output.

–CVI DVR does not support the resolution  of the camera

–BNC interface is broken.

–AD register is broken.


–BNC Cable is broken

【Dark image at night】

Problem description:

The live image is very dark at night.

Possible reasons: 

Wrong image parameter 

ICR is not enabled. 

ICR is broken cannot switch automatically.


Check the image setting is normal, especially the brightness parameter. You’d better default these values to have a try. 

Enter the OSD of the camera and check its W/B mode.

Change the mode of ICR to see if the ICR will switch automatically. If the ICR can switch but the image is still dark, then it’s the fault of the IR light. Replace the  light. If the ICR cannot switch, then the ICR is broken and replace the ICR. 

【IR reflection 】

Problem description:

The image is normal at daytime, but at night, there is a white region or a strong light in the image.

Possible reasons:

The camera is too close to the wall or the floor and the IR reflect into the camera.

There are some obstacles in front of the camera and the IR reflect into the camera.

Sun shield is adjusted improperly or is white, and the IR reflect into the camera.

For the dome camera, there is gap between  the cop cover and foam, the light leaks. 

The lens and foam installed improperly, the light leaks. 


Adjust the camera installation height, position and direction.

【Stripes in the live image】

Problem description:

There are stripes in the live image

Possible reasons:

Centralized power supply interference 

Bad power supply

Poor quality cable or loose connection

Device fault

The camera is installed in elevator and the camera is not isolated from the elevator, the running elevator will interrupt the camera.


Use Dahua integrated mount tester to test the camera, if the image is ok on tester, then replace the BNC cable. If not, power the camera with the tester, if the image is ok on tester, then replace the power. If still not ok, then it’s the camera fault and go for RMA. 

【The image is pink or slight red】

Problem description:

The image is pink at day time, the image is normal at night. 

Possible reasons:

White balance or image parameter wrong.

ICR fault cannot switch.

Low power supply, ICR cannot switch as the camera needs higher power supply when the ICR is on. 


Default the image parameter and white balance parameter to see if it will be normal.

Check the ICR mode if it is auto, set the mode to color mode to see if the image will turn normal.

Enhance or increase the power supply. If the camera is centralized powered, then change it to independent power supply to see the ICR will switch automatically. 

If the methods above are all tested and with no success, then go for RMA. 

【Intermittent recording videos】

Problem description: 

General all day recording is enabled, but when searching the video, the videos showed are intermittent.

Possible reasons: 

If the missing video is at the same time every day, check the auto reboot is enabled or not

If the missing video only occupies several seconds, check the NTP is enabled or not.

If the missing video is about 4 minutes, maybe it is caused by abnormal reboot.

If the missing video is around 10 minutes, 1 hour or even several days, check if the device is powered off or not.

【CVI DVR Rebooting 】

Problem description: 

The customer is complaining  the device is rebooting randomly with no reason.

Possible reasons:

Abnormal decoding or recording

The device is overloaded

Firmware bug 

HDD fault

Reading/writing log stuck

Power supply abnormal 


If XVR reboots immediately after it is powered on, please get rid of the camera and HDD to see if it will still reboot. 

Enter the local menu, check the log of the device. Choose type as system operation, choose the frequently rebooting time, search the log and check the error code. 

Get the serial print log via U disk or get the serial port printing and send it to Dahua R&D.

Device log information on web menu:

【No signal on VGA monitor 】

Problem description: 

When the VGA monitor is connected to the CVI DVR, there is no signal on the monitor. 

Possible reasons:

Unmatched resolution format between the DVR and the monitor. By default, the output resolution of the CVI DVR is 1280*1024. But for some old monitor, it only supports the resolution up to 1024*768. 


Login to the web menu of the CVI DVR and change the output resolution of it.

Path: DISPLAY-Resolution


What’s the recommended installation height of CVI camera?

There is no definite standard. It depends on the actual installation scenarios. Generally speaking, it is around 3 meters and there should be no shelters in front of the camera.

The image is white and black in the day time.

Check the ICR mode is auto and make sure the camera is in the place where the light is enough.

How to switch the output signal of the CVI camera?

If the camera has dip switch, you can use it to switch the signal. If the camera has no dip switch but supports 4 signals, then you can switch it via OSD menu. Also you can use UTC controller to switch it. 

The camera’s output resolution is low and the image is blurred.

Check the camera’s video format is changed or not, then check the DVR’s output mode matches the camera which should support this camera’s resolution. 

The motorized CVI camera’s image is blurred, out of focus when opened.

Check the motorized lens is fixed well, the image will be blurred if there are some vibration in transport. So please implement auto focus function can solve this problem. 

ICR switches frequently at night.

Check if there are shelters in front of the camera or there are flickering strong light in the scene.

How to enable audio function in the system?

If the camera supports audio, enter OSD menu – advanced- audio mode, set mic in or external mode, also enable the coaxial audio function in CVI DVR side. 

Cable selection in CVI system

We recommend 75-5/75-3 cable in domestic market, RG59/RG6 in oversea market. If the transmission cable is network cable, you need a pair of balun to convert the signal. But notice that there will be noise in audio transmission when using balun. 


Cable and interface




Structure components

Camera fog inside


dark image

No signal on local live view

Pink image


Recording issue 


No signal on VGA output


the end