Cctv Problems - Help Please

[mesteptoe]

I have had a 674DVR and 4 Sony 36IRVF 420 cameras in a system for about 6 months. Each of the cameras has a separate power supply (12v, 1.5 amps on the units, which came with the system). Each camera is linked to the DVR via 4 No. 20m cables which combines video, power supply and audio (not used). The cable came with end connectors so I didn't cut the cable to exact lengths. As regards viewing, this is via a CRT TV using a scart connection.

All was connected up and it worked fine for about 3 months. The picture then deteriorated on each camera - faint horizontal and diagonal lines appeared, moving slowly down the screen. At night, when the infa-red came on the pictures started to flicker - so much so that the alarm was triggered on the DVR, i.e. video loss. Presumably the power requirements of the infa red doesn't leave enough for the cameras.

I suspect that there is some loss of power along the 20m cables, although I have checked that 12V is still available at each camera. I note that the Specification for each camera is 12v 400mA - bit strange because they came with 12V, 1.5amp power supplies. If I connect the power supply direct to the camera, i.e. omitting the 20m cable, it works fine again - but it is not convenient to run extension leads to each camera and solve it that way. I did wonder whether the power supply cable was of inadequate size to take the required current so I tried using 2 core 0.75mm2 cable - but camera didn't turn on at all. The system supplier did suggest I connect the unused audio cable to the power supply cable in parallel - to beef up the cable a bit, but this made no difference. I have managed to get a camera to work using a different power supply (supposedly 12V, 200mA but it actually registers 21V on a meter). But I am a bit worried the increased voltage may damage the camera.

Does anyone have any idea what might be happening and advice on how to solve it without running extension leads to inaccessible places. Maybe I need different power supplies, or cable which can supply the correct feed to the 12V 400mA cameras.

Any suggestions much appreciated.

Thank you.

Graham

[PeterJames]

Could be power supplies, could be mains induction on your cables (Have you run your cable close to mains?) or it could be cheap cameras worn out, try a camera plugged directly into the dvr if you lose the lines and you know the cables are nowhere near any mains its most likely the psu's. If the lines are still there its the cameras

[magpye]

Have a look here

http://www.tectonrd.demon.co.uk/humbug.html

[james.wilson]

cant see how a humbug will help magpye?

As pete says try conecting directly to dvr on a sort cable to prove the kit.

Plus its not a sony camera. If it was it would have sony all over it. It has 1 sony component in it among thousands of components.

[tomcctv]

i would get shut of the cheap cable kits. they dont last long .... and do give problems. it is something you would have to do anyway.

[sixwheeledbeast]

The cheap cable kits are normally of poor quality and the conductors are too thin for the current at that length.

That said if you have tried to "beef it up" to no avail, sounds like you are looking at a PSU fault.

I wouldn't run a 12 volt camera on anything like 21 volts either, it may work but in the long run it's damaging the kit.

Although this could be a sign it's the cabling.

The PSU's should be rated with the correct polarity, voltage and supply adequate current to run the cameras.

Try testing all the kit near the DVR to prove the kit.

Also try testing the voltage of the PSU with and without load (the camera), in both locations (next to the DVR and locally).

If you can check the voltage with the IR's on too.

These values with help diagnose if the PSU is faulty/suitable.

If new cable is required "Shotgun" RG59+2 Core will be suitable, try to get a large conductor on the 2 core, 0.75 or more will be better.

Remember you will need to buy and put connectors on the ends of the cable, it's not pre-made rubbish.

[fozzies]

If you plug each camera individually direct into your monitor,do you get the lines on all cameras? Completely bypassing the dvr i mean

[mesteptoe]

A lot of comments above, thanks for the interest. Perhaps I could make comment on some of the points raised,

1. Currently the multi cable from the DVR to the monitor runs directly alongside the extension cable supplying the 4 psu's and the DVR. I did think that may be an issue and so ran a completely separate extension away from the multi cable - but the interference was still there.

2. Don't think they were cheap cameras. I thought they were Sony but what's written on the box is Model 36IRVF420, Sony CCD,1/3", 420TVL, 3.5 - 8mm V/F lens, Power DC12V 400mA. But, quite right, they are not Sony as it says HENELEC on the side - misleading selling by the retailer there. Strange that they work okay when directly connected to the psu.

3. I did wonder about a ground earth loop and the "humbug" but surely the fact that I can get them working by connecting the psu direct cuts that out.

4. If the camera has 12v 400mA written on it does anyone know what psu spec. I need to supply down 20m of cable? One comment states "adequate current" but what is that? As I said above the psu's supplied have 12V, 1.5 amps written on the back - I have checked the 12v at both the outlet and at the end of 20m cable.

5. I have tried connecting the camera direct to the monitor, i.e cutting out the DVR - no change.

6. I am not sure how to check the voltage after connecting the camera or the IR as it not very accessible for a multimeter then.

7. Is "Shotgun" RG59+2 core two separate cables, i.e. the RG59 for the video and the 2 core (0.75 or more)for the power. If so I have already mentioned that I tried replacing one of the long power supply cables with 2 core flex (0.75mm2). Although it registered 12v at the end, the camera did not work at all.

Still no nearer sorting it out then. The strange thing is that it all worked fine for 3 months. Please don't give up on this one.

Thanks

Regards

Graham

[PeterJames]

A lot of comments above, thanks for the interest. Perhaps I could make comment on some of the points raised,

1. Currently the multi cable from the DVR to the monitor runs directly alongside the extension cable supplying the 4 psu's and the DVR. I did think that may be an issue and so ran a completely separate extension away from the multi cable - but the interference was still there.

2. Don't think they were cheap cameras. I thought they were Sony but what's written on the box is Model 36IRVF420, Sony CCD,1/3", 420TVL, 3.5 - 8mm V/F lens, Power DC12V 400mA. But, quite right, they are not Sony as it says HENELEC on the side - misleading selling by the retailer there. Strange that they work okay when directly connected to the psu.

3. I did wonder about a ground earth loop and the "humbug" but surely the fact that I can get them working by connecting the psu direct cuts that out.

4. If the camera has 12v 400mA written on it does anyone know what psu spec. I need to supply down 20m of cable? One comment states "adequate current" but what is that? As I said above the psu's supplied have 12V, 1.5 amps written on the back - I have checked the 12v at both the outlet and at the end of 20m cable.

5. I have tried connecting the camera direct to the monitor, i.e cutting out the DVR - no change.

6. I am not sure how to check the voltage after connecting the camera or the IR as it not very accessible for a multimeter then.

7. Is "Shotgun" RG59+2 core two separate cables, i.e. the RG59 for the video and the 2 core (0.75 or more)for the power. If so I have already mentioned that I tried replacing one of the long power supply cables with 2 core flex (0.75mm2). Although it registered 12v at the end, the camera did not work at all.

Still no nearer sorting it out then. The strange thing is that it all worked fine for 3 months. Please don't give up on this one.

Thanks

Regards

Graham

They're Sony chipped so they can retail them as Sony, Sony sell different quality CCD chips and reject chips these end up in cheap cameras (Anything less than £100 per cam is cheap a decent Sony chiped Camera will be twice that)

The camera will draw as much current as needed remember the cable will consume current as well so 1.5 amp is a sensble psu assuming that its a decent regulated psu again cheapo psu can leak ac.

When you say you have plugged the camera directly to the monitor, did you mean as fitted or did you remove the camera from its installed position and plug it directly in the back of the camera, if the picture is still u/s plugged directly into the monitor you know the camera is the problem

[fozzies]

Might be worth checking the scart to bnc lead too. if all cameras are individualy giving the same fault, it would be strange for all 4 to fail in the same way at the same time.

Unless your using 1 pair cable for the power , id imagine the psu,s are adequate.

i think your looking at a common element failing, rather than a camera/ cable problem, unless its an induced current