CJ04 0 Posted April 29, 2009 I've been interested in this topic and finally decided to give it a try at home. This is my first installation and a low budget one. I thought the DVR programming and Internet monitoring would be the greatest challenge but it turned out working fast. The problem actually lies with powering the cameras and here I'll appreciate any guidance. This same problem occurs in two different camera locations at home. After doing the cutting/cramping & soldering of the camera pwr supply barrel connector I measure the voltage correct at both ends of the wire, but the camera (tested) does not work. I have two pairs on each run and I have also tried unsuccessfully to use them combined, I realize there is a voltage drop but distance is less than 50 feet and related charts I've seen do not show any major drop. Any suggestions ? TIA. AVR761 Model 4 2xQ-see 30ft night / Color Sony Sensor 12VDC 200mA 1xQ-see 100ft night / vision Sony Sensor 12VDC 1.5A Share this post Link to post Share on other sites
zmxtech 0 Posted April 30, 2009 test the cams next to the DVR with short leads first. then you can use a small12v battery at the end -to power the camera to see if its a "power" problem. z Share this post Link to post Share on other sites
scorpion 0 Posted April 30, 2009 I am willing to bet that you have power at the camera, but the video is the problem. Take a small TV that has the yellow video input on it, and set it up on your ladder, and plug in the camera. If you see video then the voltage side is ok. You might have the wires reversed? If you put pigtails on the end of the wire for the camera then the pigtail may not match the camera power lead just right. I have seen this but it is very rare. It could be just the one individual style, or just the one connector only. Share this post Link to post Share on other sites
Soundy 1 Posted April 30, 2009 Silly question, but are you sure your power connections are the proper polarity? With most 12VDC cameras with barrel connectors, the "tip" should be positive and the shield is ground. Share this post Link to post Share on other sites
CJ04 0 Posted April 30, 2009 test the cams next to the DVR with short leads first. then you can use a small12v battery at the end -to power the camera to see if its a "power" problem. z Thanks zmxtech, done that. In fact I have good video if I use the power supply connected directly to the camera (by using several extension cords). Share this post Link to post Share on other sites
CJ04 0 Posted April 30, 2009 Silly question, but are you sure your power connections are the proper polarity? With most 12VDC cameras with barrel connectors, the "tip" should be positive and the shield is ground. Thanks Soundy. Yes I am sure, tip is positive, shield is ground and polarity is verified with my voltmeter. Although I must confess I also tried reversing polarity to check, with the same results (power supply still works ) I have the same DC level and polarity in my connection to the camera as I have in the IT room where the power supply is. Share this post Link to post Share on other sites
CJ04 0 Posted April 30, 2009 I am willing to bet that you have power at the camera, but the video is the problem. Take a small TV that has the yellow video input on it, and set it up on your ladder, and plug in the camera. If you see video then the voltage side is ok. You might have the wires reversed? If you put pigtails on the end of the wire for the camera then the pigtail may not match the camera power lead just right. I have seen this but it is very rare. It could be just the one individual style, or just the one connector only. Thanks scorpion. Actually I have video in the DVR (located in the IT/Washer/Dryer room) when I put power directly into the camera, by way of several extension cords. So I know video is fine. Could it be possible to have the cable stapled against an aluminum stud affecting the ground connection ? while still having the DC voltage correct at the camera end. Share this post Link to post Share on other sites
scorpion 0 Posted April 30, 2009 Thanks scorpion. Could it be possible to have the cable stapled against an aluminum stud affecting the ground connection ? while still having the DC voltage correct at the camera end. This would tell me that the Jacket of the power wire has been pierced? Is this correct? In other words the power lead ground goes through the staple, and in to the metal stud? Share this post Link to post Share on other sites
survtech 0 Posted April 30, 2009 Actually I have video in the DVR (located in the IT/Washer/Dryer room)... A suitable place. I've always wanted to "clean up" our IT Department! Share this post Link to post Share on other sites
scorpion 0 Posted April 30, 2009 LOL! That was a good one!! Share this post Link to post Share on other sites
mr.surveillance 0 Posted May 1, 2009 Have you tested the voltage on the camera end with the camera connected? If its a cable problem it may check OK with no load and only show a voltage drop when the camera is drawing power through it. Good Luck! Share this post Link to post Share on other sites
CJ04 0 Posted May 1, 2009 Have you tested the voltage on the camera end with the camera connected? If its a cable problem it may check OK with no load and only show a voltage drop when the camera is drawing power through it. Good Luck! Thanks for your input, I'll test it as soon as I get home later today and post the results. If I understand what you're saying, without the camera there is no closed circuit, therefore no current and hence no voltage drop. If so, there would be a voltage divider between the cable resistance and the camera. Increasing the voltage source, assuming cable load is not very big, should help bring the voltage back to operating parameters, although power consumption won't be close to optimal. CJ. Share this post Link to post Share on other sites
Soundy 1 Posted May 1, 2009 Nothing that complicated, really... sometimes you get a bad or flaky power supply that will measure full voltage with no load, but can't provide any current when there's even a small load on it, and the voltage will drop out. In that case, a new power supply is all it takes. Share this post Link to post Share on other sites
CJ04 0 Posted May 1, 2009 Actually I have video in the DVR (located in the IT/Washer/Dryer room)... A suitable place. I've always wanted to "clean up" our IT Department! Share this post Link to post Share on other sites
CJ04 0 Posted May 1, 2009 Nothing that complicated, really... sometimes you get a bad or flaky power supply that will measure full voltage with no load, but can't provide any current when there's even a small load on it, and the voltage will drop out. In that case, a new power supply is all it takes. Thanks for keeping contact on this issue. I've measured voltages at power supply and camera ends, with and without load (camera) and the result is the about the same. I've several power supplies, tested & working with other cameras, and the result is the same. The only way I get video on the DVR is when I connect the power supply (any of the ones I have) directly at the camera location, hence bypassing the power wire-run. I'm about to give up and run a cable to the garage, not easy, but is the nearest power source. Any last thoughts ? Anyone.. Share this post Link to post Share on other sites
kensplace 0 Posted May 1, 2009 Although I must confess I also tried reversing polarity to check, with the same results (power supply still works ) Have you tested the cameras again with a local power supply after you tried reversing the polarity. Are those cameras reverse polarity protected, if there not they could be damaged now. Share this post Link to post Share on other sites
Soundy 1 Posted May 1, 2009 No more ideas, sorry... that's a strange one alright. What IS the actual voltage reading AT the camera? Share this post Link to post Share on other sites
CJ04 0 Posted May 1, 2009 Although I must confess I also tried reversing polarity to check, with the same results (power supply still works ) Have you tested the cameras again with a local power supply after you tried reversing the polarity. Are those cameras reverse polarity protected, if there not they could be damaged now. Kensplace, I would doubt they have any sort of protection, they are low budget q-see. But in answer to your question, yes cameras are still working and using those same power supplies. Share this post Link to post Share on other sites
CJ04 0 Posted May 1, 2009 No more ideas, sorry... that's a strange one alright. What IS the actual voltage reading AT the camera? It is strange alright, but I'm grateful for everyone that suggested options, it is a good community. q-see power supplies, rated at 12Vdc 200mA (tried 2 on same wire run) is 18V at both ends. Another power supply, rated 12Vdc 400mA, actually gives 12Vdc. CJ Share this post Link to post Share on other sites
zmxtech 0 Posted May 1, 2009 200mA is not much that would be pushing the limits on a long run. I would be using 1A supply's at least. and> TDR the line, look at the DC volts on the line with a CRO to check for any hanky signals. z Share this post Link to post Share on other sites
Sawbones 0 Posted May 1, 2009 200mA is not much that would be pushing the limits on a long run.I would be using 1A supply's at least. and> TDR the line, look at the DC volts on the line with a CRO to check for any hanky signals. z I agree with this... 200mA is pretty weak. You really want a beefier power supply than that. Share this post Link to post Share on other sites
