CCTV Question

[blinkers 0]

Hi folks, New to forum.

 

 

Replaced a cctv camera with one that was not working. The new camera ( is a working camera ) still does not work properly.

 

The RG 59 passed on my cheap little paladin tester. No matter what port I try on the DVR- still the same result. The picture shows up great for about fifteen minutes on the monitor and then goes a redish black color and you can't see anything.

 

Seem to be getting the correct voltage 24 VAC that all other cameras are working of.

If the BNC connections were bad - how would it pass & would it work for fifteen minutes and then stop?

 

Any help appreciated.... thanks

[Soundy 1]

Welcome!

 

So if I follow this: you had an existing camera that stopped working... you replaced it, and the new camera works for 15 minutes (is it always the same? is it 15 exactly?), then goes dark... and it does this no matter which input you connect it to on the DVR?

 

The time frame suggests it might be something heat-related - is this camera in a tight, enclosed space or a warm location?

 

Are you still reading 24VAC at the camera when it's dark?

 

Can you try running another signal line from the camera to the DVR (doesn't need to be "installed", just run it across the floor and through doors or windows) for the purpose of testing?

 

How about disconnecting the existing cable run from the DVR and feeding it straight into the monitor?

 

When you swapped the cameras, did you put the old lens on the new camera? And if so, is it an auto-iris lens?

[ptzguy 0]

I had this problem(or sounds very similar) with a few eyeball domes(generic gimbal type), turns out it was a faulty batch of them. They were model benqxxxx and metallic purple in colour, they also blacked out during storms(when there was static in the air) and only came back on if you unplugged the power lead momentarily. Strange as they're supposed to be lightening proof!

I got no proper explanation from the supplier but they exchanged them for some Eneo domes.

[blinkers 0]

Welcome!

 

So if I follow this: you had an existing camera that stopped working... you replaced it, and the new camera works for 15 minutes (is it always the same? is it 15 exactly?), then goes dark... and it does this no matter which input you connect it to on the DVR?

 

The time frame suggests it might be something heat-related - is this camera in a tight, enclosed space or a warm location?

 

Are you still reading 24VAC at the camera when it's dark?

 

Can you try running another signal line from the camera to the DVR (doesn't need to be "installed", just run it across the floor and through doors or windows) for the purpose of testing?

 

How about disconnecting the existing cable run from the DVR and feeding it straight into the monitor?

 

When you swapped the cameras, did you put the old lens on the new camera? And if so, is it an auto-iris lens?

 

 

 

Thanks guys,

 

Tried connecting it three or four times. fifteen just an estimate. Doesn't always show up when you connect it. It did show up twice - right after I tested the cable with for opens or shorts and it passed both times.

 

Camera outside. Heat not an issue. Every other camera that goes bad we just replace it with a new one and it always shows up on the monitor. We just adjust and focus and job done.

 

Tried different ports in DVR that I know work. Same result. Camera a good two - three hundred feet away from security desk. can't really run one through the premises. If I do need to pull a new cable. Which is the most reliable for these kind of distances?

 

Why put old lens on new camera? sorry not familiar with this line of work.

 

Is there a good book to get started with in learning about the whole cctv game. Both residential and commercial applications?

 

Thanks guys

[Soundy 1]

Tried connecting it three or four times. fifteen just an estimate. Doesn't always show up when you connect it. It did show up twice - right after I tested the cable with for opens or shorts and it passed both times.

Alright, that sounds more like an interconnect issue - either bad terminations, or a bad cable run.

 

Tried different ports in DVR that I know work. Same result. Camera a good two - three hundred feet away from security desk. can't really run one through the premises. If I do need to pull a new cable. Which is the most reliable for these kind of distances?

RG59 should be fine for those distances... just make sure it's good quality stuff, and it's solid copper center conductor and 95% braided copper shield. Foil shield and copper-clad steel center conductors (or worse, both together) are well known to be problematic.

 

Why put old lens on new camera? sorry not familiar with this line of work.

You didn't specify what type of camera it is, but when using box cameras, it's not unusual to replace a dead camera but reuse the old lens, because box cameras don't typically come with a lens... and sometimes if you get a "specialized" lens (extra-wide or extra-long, for example), it's harder -and more expensive - to find a replacement.

 

The thinking here is, with an auto-iris lens, the iris sometimes stops working (either the camera's iris drive fails, or the iris itself fails in some way), and swapping the old lens onto the new camera just shifts the problem. Your description sounds like you're losing brightness, but not necessarily the video signal (or the DVR would report "signal loss"), which would be a common symptom of a failing iris.

 

Is there a good book to get started with in learning about the whole cctv game. Both residential and commercial applications?

Not that I've ever seen... but then, I've never looked

[blinkers 0]

Thanks Soundy for your sound advice.

 

You hit the nail on the head with losing brightness and not the signal. I just didn't understand why it would pass a cable inspection and work for fifteen minutes if it was a bad termination. However I'll try new bnc connectors and also a new power source before I go pulling in a new run.

 

Thanks for all your help!

[Soundy 1]

Can you confirm whether you're getting signal loss or not? If you disconnect a working camera, does the DVR tell you there's signal loss on that channel?

 

Do you have actual make and model names for these cameras? Can you tell if they have auto-iris lenses (normally will be a wire running up to a small motor on the side of the lens)?

 

The problem really doesn't sound like cabling to me... but even if it is, a simple continuity test won't always reveal a bad termination - it could be intermittent, or if it's just a poor connection, the increased impedance can cause problems at video frequencies that will never show up with DC voltages used by continuity and resistance tests.

 

I suggest before actually pulling a new cable through the ceiling/walls/whatever, just running it through the halls if at all possible, to test it... if that works, then your existing run is your problem, and you can pull the cable properly. But before confirming that, you might not want to go through the hassle of installing a new run, only to discover that's not the problem.

[blinkers 0]

Thanks again Soundy,

 

I got back to the job yesterday and found the problem.

 

It was an outside camera that was whipped from a surface box. The wire in the whip had been damaged - probably when they pulled it in, just enough to remove the insulation. This was then covered with tape and water had been getting into the whip, through the top of the box.

 

My first tester had passed it and that's when I tried new ends and had it working for fifteen minutes.

My second tester did not pass it until I found and repaired the problem.

 

I could squeeze the damaged coax with my pliers and see the water oozing out.

 

Thanks for the help guys!!