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June 3, 2016
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I have a very weird problem with one of my BNC wired cameras.
This camera is in an 8 camera system. I have two transformers supplying camera power, and have switched power supply plugs several times, trying both transformers and several separate wires. Local line voltage is a steady 119.
I've been very careful to make sure all connections are clean and good, especially the coax ground to the camera and DVR which didn't quite seem secure at first.
The other 7 cameras work well, no matter which power supply or power connection is used.
I can switch the camera connection on the DVR, the problem follows the cable and camera, not the display location.
The picture on the problem camera is bright, clear, and consistent as long as there is any light outside. Once there is no daylight outside, the picture is noticeably darker than the other cameras.
At random times, the already low brightness will fluctuate, becoming noticeably darker, then recovering, then slightly darker, etc.
Also, usually before, after, or during this time, there may or may not be very short duration horizontal lines on the picture. The lines don’t seem to move, just appear and disappear.
At some times when the picture is darkest, there may also appear very black lines horizontally across the picture. These may be pretty thin (maybe just a few percent of the picture height), or very thick (like about ⅓ to ½ the picture height).
Maybe one of 10 times the darkness, lines, etc. appear, the camera will disappear to the system, showing the same indications as if there is no camera connected. This may last from a few seconds to maybe an hour or two. Then the camera will just reappear by itself, looking like it did just after dark.
All these problems may or may not appear multiple times through the night. Next day all is fine - until night arrives again.
This situation is not easy to just swap out the components (cable and / or camera) to isolate the problem as both are very difficult to reach. I’m hoping that someone here with lots of experience can use that experience to help me nail the problem down.
Thanks!
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May 15, 2015
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Hi Roger-
The problem you are describing sounds very much like a power issue on that line. Is that a long cable run?
If it is longer than 180 feet, you might be experiencing voltage drop on that line. This is magnified at night when the IR LEDs come on. (Voltage drop increases as the load increases)
Have you tried swapping a known good camera to that cable? That is the best way to troubleshoot the cable and power. Sounds like you have isolated the issue to that particular cable/camera - now the last step is to determine if it's the cable or the camera. Swapping it with a known good camera is the best way to sort that out. That will also show if that camera is good on a different line. That would be my first suggestion to troubleshoot it.
June 3, 2016
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The cable run is 60 ft. The power comes from a transformer at the DVR end, so 60 ft for that too. I'm using one of the larger diameter cables, not the really skinny type.
I can't easily swap out cameras, I prefer to take a shot at either cable or camera and get one. I could pull one of the other cameras and swap it in there, but it's a difficult to reach location, and switching really multiplies the work, since these cameras are REALLY difficult to aim and this is a difficult place to get to. I may end up doing this, though.
Another new detail - I have a 15v power supply (std is 12 v) at hand, and tried this at one time when the screen was black. The camera came back on line with a VERY bright picture, very bright infrared illumination - so bright I guess I was overdriving the camera, so I immediately unplugged it and went back to the 12V. The camera went back to working the way it was. This was only a one time thing, though I plan to try it again on the next long lasting black screen. Does this provide any more clues?
Thanks!
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May 15, 2015
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Roger -
It looks like cable length is not an issue then. It could be interference though - are there any high power lines close to your cable run? (Or anything that would emit RF interference, like high power motors, flourescent lighting ballasts, or microwave or anything like that?)
As for the 15V power supply - definitely a 'no go' unless you have really long cable runs - enough to produce a 3V drop in the cable. That 15 V on a short cable is enough to burn up the camera. If that was the same camera - then it still points to a low power condition - the higher voltage was enough to get it fully powered - but that is obviously not an option for the long term.
I hate to say it, but I think swapping that camera for a known working camera is the only good test to isolate whether it's a cable or camera problem. If swapping the cable itself is somehow easier - that's worth a try, but it leaves open the possibility of a routing issue where the new cable could be subject to the same RF interference. (if RF is the issue) That would make it appear to be the camera, because you swapped to a new cable - but if it's RF, the new cable would act the same. That's why i say the only definitive test would be to swap a known working camera to that position= if it also messes up, then there is an environmental issue pointing to the cable, or rarely, there may be high RFI at the camera mount position. (That's usually pretty unlikely)
The only other good test is to pull that camera down and test it on a short cable. (6 or 10 foot) If it tests good on a short cable...once again that would point to a cable issue.
Sorry I can't think of an easier way to test that doesn't involve taking the camera down.
June 3, 2016
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I understand.
You mention about "high power" lines - there is a regular outdoor 110v wire running close to, but not next to (maybe 3" away), this cable run for maybe 15 or 20 ft. However, this has been true since initial installation about 3 years ago, and this problem is now maybe 2 months old. What is your opinion about this being a possible problem?
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You have given the best answers so far, so I want to ask a different question. If you want, please move this to it's own question, just please subscribe me so I get notifications.
In the past, on the 12v power supplies, I had one of the other coax cables (not this run) burn in half about halfway to the camera. This was in an attic area, so that's scary to me. There was no other damage I could see, system or woodwork. Is this even remotely common? Everyone assures me that this was so rare that I'm not sure they believed that it really burned in half. Should I be using a fire rated coax? Is there such a thing? Some other precaution?
Thanks!
Members
May 15, 2015
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Roger -
The 110V line could well be causing interference if they are running parallel for that distance. A good rule of thumb for separation would be to keep them 8 ~ 12 inches apart at minimum if possible. (Crossing a high power line at right angles does not affect you as much as running parallel) If the camera is 3 years old and this problem has just started - the camera itself may be producing a weaker signal now, and just starting to allow the interference to affect it. (All electronics degrade over time with use) If possible - see if you can get some more separation in that 15~20 foot run. That may be our culprit.
As for the 12VDC line burning the cable in half - I am guessing it was siamese cable (coax with the 12 volt lines attached as a seperate cable) Did that burn through the coax as well, or just the 12VDC part? I have been in this industry for 14 years now and have never heard of that happening. Usually the 12VDC is fused or has thermal breakers in the supply side that should have killed the connection before it gets that hot. (referring to a 12VDC power box where all cameras connect to same power supply) If you were using 'wall warts' they may not have that same protection though. Rest assured that is a pretty rare occurence for a 12VDC line in any case.
June 3, 2016
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I understand about the 110 line, and will have to consider that. Maybe if the line is replaced I can run it along the house side instead of under the eaves.
The toasted cable was a round cable, like this one (omited link), but pretty sure it is 60 ft, not 100 like this one.
The power supplies are the "wall wart" type. What should be the voltage of these two power supplies with three leads plugged in, checking voltage on the fourth? Is there anything I can add that might reduce the risk of wire overheating?
Thanks!
Members
May 15, 2015
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Roger,
What is the possibility that a critter may have chewed the wire? That's pretty uncommon for a siamese to burn through for no reason.
Especially from a 12 VDC power supply. Your wall warts should be 12 VDC with a minimum of 1 Amp for each camera.
The best protection against any overheating would be to use a power supply that has internal fuses or thermal breakers. Most professional power supplies have that. It also makes for a lot cleaner installation to have a single power supply instead of all those wall warts. here is an example of a 16 channel supply = https://www.securitycameraking.....-prd1.html
June 3, 2016
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Not unless a critter has flaming teeth... I'm looking at it right now, and the wire broke into two pieces, with charring around the break. Insulation is bubbled just beyond the charring. The metal wires are still mostly copper colored, but do appear slightly rounded at the break point. As I remember, it was hanging by a few of these remaining wires when I discovered it. I can send a picture if you want, if there is a way on here.
There are no gnaw markings near the burn area, or anywhere else I can see.
You mention "siamese" wires, I guess that applies here, with a round outside shape with a plastic outside covering? The inside wires would be +, -, and video.
Is there a way to check these wires with a multimeter? How much resistance between the two hot leads, and the hot leads to the video? I also have a checker ( GET-4220T Lan Tracker/Line Tester), but not sure how to use it, or even if its applicable for this.
There are only two "warts", each with 4 power leads coming out (8 cameras). They are 12v, 3A output each. That gives a bit less than one amp per camera. Most of the runs are 60 ft, I think there is one 100 ft (not the problem camera).
The power supply you show looks interesting. How do the power plug ends connect? I just see screw terminals. Use pigtails with connectors, or?
Thanks!
Members
May 15, 2015
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Ha ha! I've seen those little beasts with flaming teeth! What I was thinking was something gnawed on the line just enough to break the insulation and cause a short - then the current would have taken over and melted the line. (still pretty far fetched idea) I was thinking another possibility is a lightning strike - where the lightning chose that point to exit the line and jump to something nearby that was grounded. Seems like you would be able to find burns on something else close by if that were the case.
When I say siamese cable - that is generally a standard coax cable (RG-59 or RG-6) with an 18/2 conducter attached to the outside of it. They are not molded inside the same insulation, but just attached - that way you can pull them apart at each end to get to the two different end points of power and video. At the DVR end you would split them apart several feet - run the 18/2 to the power source and the coax to the DVR.
As for testing - the only sure test is to disconnect the cables from camera and DVR - (have them connected to nothing)- then run a continuity test - there should be no connection between any of the 4 leads (coax center line / coax ground / 12V + / 12V -)
Now - I have assumed that you are running coax or siamese cable because you mentioned BNC connectors - but you mentioned the wiring earlier and it gave me the impression you may be using Cat-5 with baluns at each end. (Cat-5 is network cable with 8 wires inside it twisted into 4 pairs) That kind of wire could be burned through a LOT easier than siamese. Wires are thinner and there is a lot more possibilty of something shorting due to defective insulation.
And then the power supply - yes it has screw terminals for power output. (+ and - for each camera) That is where you would just pull a siamese cable apart - the 18/2 would run directly to the power supply - no ends needed - just screw them down, and the coax goes to the DVR and attaches with BNC connector.
At any rate - having a line burn like that is not just uncommon, it is a little odd! I would think the possibility of that happening again are fairly astronomical.
June 3, 2016
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It would be possible to just be gnawed at the one place, but where I've seen gnawing before it's spread around a bit, at least like a half an inch or so. And I'd be really surprised if anything like that could even reach it - but I've been really surprised before. A nearby lightning strike is a real possibility, though if this cable was the ground path lots more would be toasted, like probably the entire system? My best guess at this point is a kink or other stress (pulling too hard?) during installation that caused minor damage, but enough to increase (no short) or decrease (short) resistance at that point.
Also, with 3 amps available across 4 equal power wires, if one of them had less resistance due to damage or whatever, then up to almost 3 amps could be available(?) to that one damaged point, maybe allowing this kind of toasting? How much current is available to one wire, at a dead short on that one wire, with the power supply you mentioned before the breaker pops? I'm assuming that there is a breaker for each lead, or I think the available current could be lots higher?
With that description of siamese cable, it does match my thought of something like O8 or Oo shape. This one is a coax, just one O shape inside one molded jacket. This one is about 3/16" cable diameter, and is "factory split" at each end into the video connector and a power plug type connector for the 12v. All the splits and connections are molded and insulated, like this one -
I have seen some with only about 1/8" diameter. These are also cheaper. These just seemed to me to be... cheaper, less well made, though I might be wrong.
Thanks!
January 3, 2014
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Roger,
What are the models of the cameras, recorder and power supply?
Jose Malave - IT Director| Toll Free: 866-573-8878 | E-mail: support@securitycameraking.com
June 3, 2016
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DVR = Q-see QC40108 - analog
Camera model - QM6008B
Power supply - Brick type - quantity 2, one for each 2 cameras, each one has a 1 to 4 splitter. Label says "CS". There are only two "warts", each with 4 power leads coming out (8 cameras). They are 12v, 3A output each. That gives a bit less than one amp per camera. Most of the runs are 60 ft, I think there is one 100 ft (not the problem camera).
January 3, 2014
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Since this is a third party recorder it is hard to provide a precise resolution to your problem. It seems to be a power issue were the cameras are consuming more amperage that what the Power supply can produce. In many cases the PSU will loose its efficiency.
I would consider upgrading to a new system. Give us a call and we can assist on this. 866 573-8878 option 2
Jose Malave - IT Director| Toll Free: 866-573-8878 | E-mail: support@securitycameraking.com
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