No image on screen (NVR & DVR)

Hold the right mouse button down for ~8 seconds (until you hear a beep), this will force change the resolution.

Repeat up to 4 times until image is displayed.

No online connection via Powerline Adaptor (NVR & DVR)

Connect the recorder LAN port directly to a router LAN port via Ethernet.

Login to the recorder, navigate to: "Settings" > "Network" > "TCP/IP" >Enable "Obtain IP automatically". Once the recorder obtains new IP settings (IPv4 address will likely change from the default: 192.168.1.200) take recorder back to the powerline adaptor and reconnect. 

Recorder not online when a new broadband router is fitted. (NVR & DVR)

Login to the recorder, navigate to "Settings" > "Network" > "TCP/IP", deselect "Obtain IP automatically" click Apply, then re-select it and click Apply again. This prompts the recorder to find new IP settings from the new router.

No camera audio on DVR

Login to the recorder, navigate to "Main menu" > "Camera" > "Camera Signal". Locate the "Audio Over Coax" column and enable for each camera requiring audio. 

No image from a Dahua camera on Viper DVR

Login to the recorder, navigate to "Settings" > "Camera" > "Camera signal"  - change the "signal type" for the Dahua camera channel to CVI. If the Viper DVR does not support CVI, the camera needs to be manually changed to TVI mode using a Dahua DVR or Test Monitor.