I am having the same problem. I have an 8 channel Q see system. the installer ran cat6 cables and used one of the original power supply and one he bought. Cameras were working great, i just took off the system to change the tv position and plug them back in. All cameras show great during the day however at night, there's static and some no video. The red rings/ IR are on but no video on the screen. If i remove the PS the guy bought, the next four cams on the original PS works fine at the night. When it's plug back in, all 8 stops showing. this is only at night.
Do i have to change the PS again or what can be the issue? Bare in mind, it was working fine all the time at nights, it's just how i removed the power when adjusting the tv