I have 4 standard bullet cameras and 2 PTZ cameras from Lorex. They are all hard wired to an NVR. I've had this system for about 3 years and it worked perfectly. Recently I noticed that all of the cameras lost night vision. I rebooted the NVR and removed and reinserted each wire. Still the same. I called Lorex for help and they did some troubleshooting on the PTZ camera and insisted it was a camera issue and sent me a new one. Of course it is not and that did nothing. I called them again and asked if it was an issue with the NVR and they told me no way, not possible. So basically they have no clue. Since then 2 of the bullet cameras have become very fuzzy like an old black and white movie with the lines running across it. My question is, what is causing this? Is it the NVR itself or the wires going to the NVR are maybe damaged outside? The cameras look perfect in the daytime btw. I just need a little guidance so I know what to replace. Thank you.