Troubleshooting Probability Guidance

[fred3 0]

I'm working on a Q-See QT526 DVR system with Q-See cameras and camera power supply boxes. The system was installed a few years ago and exhibits some intermittencies with "video loss". I'm a capable tech but have little experience with the system components in this application. So, I'm looking for guidance in going about troubleshooting.

Such things as: "What is more likely to fail intermittently: power, power connections, video connections, DVR video channels, cabling?"

 

The system has what I think are called "Siamese" video and power cables with identical BNC connectors at each end and DC power barrel connectors at each end (which are different at each end). These are white-colored manufactured cables that *appear* to be of good quality. ONE BNC end appears to have been replaced on one of the 16 cables.

 

The use of barrel connectors on cables only causes me a bit of concern but I have little experience using this type of in-line connector.

There are short barrel connector adapters going from the Siamese cables to the camera power supply box connectors.

(This particular power supply has 8 barrel connectors each on the left side of the box). I have to wonder .. why are these necessary? Wrong cable or...?

 

If you had a "video loss" on a system like this one, how would you assign probable causes of failure?

 

Here are mine:

 

BNC connectors - 33%

Power connectors - 33%

Power supply per camera - 10% (but looks OK in this case)

Cameras - 24% (just because I don't know any better).

 

Since the cables look "good" cosmetically and because the power seems OK (but is it?) then I can imagine selectively replacing cable end BNC connectors if an intermittency shows up more or less consistently. Is that reasonable?

 

I've otherwise done some of the obvious troubleshooting things like swapping power connectors, swapping DVR ports and swapping cameras.

One or two camera locations (i.e. cables I suppose) remain questionable nonetheless.