Swann camera not working

[thewall58 0]

I have a NVR 7400 with NHD-818cam cameras the other day one was showing video loss then after 5 hours it came back on for a week then went off and not worked since, i have changed cables, ports and tried in another position and tried a reset still no life.

Are there any other camera that are compatible with this system.

I have a mate who is very good at circuit boards does anybody know what each wire carries i.e power, sound, video etc