PoE "oooppppssss"

awsum140

awsum140

Known around here
Nov 14, 2017
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Southern NJ
OK, I admit I should have known better and made a really dumb mistake, but i was in a rush while working on my system yesterday and accidentally used a crossover cable (see what happens when you assume all your cables are straight though?) instead of a straight-through on a PoE camera. The camera is now non-functional, IE no signal and the IR didn't come on last night.

I've done a little trouble shooting, re-terminated the RJ45 at the PoE injector just in case that failed from being manhandled, but that didn't do it. I'll be checking the cable, end to end, in a little while and will also bring the camera in at that time to check it, directly, on the injector/switch. The camera is about 120 feet from the house so it's kind of a chore to check out quickly and easily.

My question is would a crossover cable being used "toast" anything, AKA let out the magic smoke, if connected to a stock camera? I would assume, and we all know what that can do, that there would be internal protections built into the camera, at least I'd kind of expect it to be. The camera is a Grandstream GXV3672HD which is a fairly decent 1mp camera and has been in service for about four years now.
 
awsum140 said:
OK, I admit I should have known better and made a really dumb mistake, but i was in a rush while working on my system yesterday and accidentally used a crossover cable (see what happens when you assume all your cables are straight though?) instead of a straight-through on a PoE camera. The camera is now non-functional, IE no signal and the IR didn't come on last night.

I've done a little trouble shooting, re-terminated the RJ45 at the PoE injector just in case that failed from being manhandled, but that didn't do it. I'll be checking the cable, end to end, in a little while and will also bring the camera in at that time to check it, directly, on the injector/switch. The camera is about 120 feet from the house so it's kind of a chore to check out quickly and easily.

My question is would a crossover cable being used "toast" anything, AKA let out the magic smoke, if connected to a stock camera? I would assume, and we all know what that can do, that there would be internal protections built into the camera, at least I'd kind of expect it to be. The camera is a Grandstream GXV3672HD which is a fairly decent 1mp camera and has been in service for about four years now.
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what poe switch/injector did you use?
 
Just a "generic" 8 port injector, WS-POE-8-48v60w Passive and it's still running three other cameras with no problems. I've tried other ports with no success and have the camera on my desk, right now, and have tried a different port and cable set. Nothing, nada, zilch, not even a link status. I suspect the magic smoke has leaked out and it's time for a Dahua. I'm going to "wring" the cable, just to make sure that's OK. I just got done trenching, putting in conduit and switching this one over to a buried line from an overhead. Jeesh!
 
awsum140 said:
Just a "generic" 8 port injector, WS-POE-8-48v60w Passive and it's still running three other cameras with no problems. I've tried other ports with no success and have the camera on my desk, right now, and have tried a different port and cable set. Nothing, nada, zilch, not even a link status. I suspect the magic smoke has leaked out and it's time for a Dahua. I'm going to "wring" the cable, just to make sure that's OK. I just got done trenching, putting in conduit and switching this one over to a buried line from an overhead. Jeesh!
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Those passive injectors power via 4-5 and 7-8 pairs...those pairs are not crossed in a standard crossover cable...but if you made the cable yourself and crossed those pairs it would result in failure because the passive injector simply supplies dumb power..
 
Yup, I think it's toast. I did make that cable for some reason and I'm not sure what that reason was, too long ago. I was hoping that there was internal protection, but I guess not. I just took the camera completely apart looking for any signs of damage, but nothing. I'll stick it back up and wait for a new camera to get here.

Ever notice how "little" hobbies/projects turn into money pits? This started out because some yahoo decided to go offroading, in the snow, across a bunch of front lawns here a few years back. I considered spike strips, but decided I'd either step on them or run them over with the mower so I put up two cameras to catch the front lawn marauders. Now, it's four camera and I want to add six more. I just bought a new router. Now I want a truly managed switch with smart PoE as well.

Thanks for your help/advice, fenderman.
 
awsum140 said:
Yup, I think it's toast. I did make that cable for some reason and I'm not sure what that reason was, too long ago. I was hoping that there was internal protection, but I guess not. I just took the camera completely apart looking for any signs of damage, but nothing. I'll stick it back up and wait for a new camera to get here.

Ever notice how "little" hobbies/projects turn into money pits? This started out because some yahoo decided to go offroading, in the snow, across a bunch of front lawns here a few years back. I considered spike strips, but decided I'd either step on them or run them over with the mower so I put up two cameras to catch the front lawn marauders. Now, it's four camera and I want to add six more. I just bought a new router. Now I want a truly managed switch with smart PoE as well.

Thanks for your help/advice, fenderman.
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if you used a proper poe switch it would not have occurred...you likely have an improper crossover cable..
 
Definitely, both are true, that's why I mentioned getting a smart, managed, PoE switch in the list of "wanna gets". When I bought that injector, like four years ago, I had no intention of ever needing anything fancier. Now, times and needs have changed. If only the wallet would cooperate.

I believe that cable was actually a "demo" cable showing how to install an RJ45, I used to manage cable plant and network installs, back in the LatticeNet/10Base5 or 2 days. When I looked, carefully, at the end I hadn't done, it was USOC so things really went awry. It got thrown in a box of cables and has been lying in wait to ambush me, which it finally did. It now has 568B on both ends.
 
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If the poe electronics in the cam got fried, then no power to the cam. eg: stepping down from 48V to 12V may not work any longer. If you can provide 12V directly to the cam, the cam may work.
You could use a poe splitter to power the cam at the end of that long cable run.....
Good luck!
 
Try running power from a direct source without using the poe function. If you get it to boot reset the camera and try again with a poe plug. The Poe injector should have been smart enough to not supply power until it verified the cable. When you initially plug in a poe cable it checks for resistances from the poe destination and does a little handshake prior to ramping up the power. If you had a wonky cable or miswired one it would just fail the handshake and not supply power. Make sure your poe is rated for the wattage required as well. I.e poe Vs poe+
 
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Darkflame808 said:
Try running power from a direct source without using the poe function. If you get it to boot reset the camera and try again with a poe plug. The Poe injector should have been smart enough to not supply power until it verified the cable. When you initially plug in a poe cable it checks for resistances from the poe destination and does a little handshake prior to ramping up the power. If you had a wonky cable or miswired one it would just fail the handshake and not supply power. Make sure your poe is rated for the wattage required as well. I.e poe Vs poe+
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see his post, he used a passive poe injector that does not have this protection...
 
Darkflame808 said:
I apologize. Thank you for clarifying. Forgive me I'm old and not wearing my glasses today. :D disregard my comment. :)
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Hey, I resemble that remark!

Seriously, I will try direct 12 volts to it after I replace it. I didn't have time to dig out a 12 volt wall wart today. It was fill in the trench day because it's supposed to snow here overnight and tomorrow. I may actually have the one that came with the camera, but fining it will be a challenge. (old age again)
 
You might want to give the camera a good disassembly if you have the patience and time. Anytime I find myself with a dead piece of electronics I always take it apart and start sniffing around, (literally sniffing) and hunt down scents of burnt popcorn. I know it's not a proper way to diagnose electronics but my nose does help me pinpoint a general area to do my diagnosing. From here I look for damaged traces or blown caps. I've repaired quite a few televisions back in the day with this method...what you should do too is analyze the Lan cable and see where the voltages were going. You might have fudged data lines and not poe lines. If luck finds you it'll be a simple fix like maybe just an overloaded cap or a hairline trace that burnt out before any of the soc's took a hit. Just rebuild the traces with a solder pen or a thin copper wire and hopefully you'll be back up and running in no time. Best of luck!
 
Darkflame808,
Excellent guidance! As an EE who designed many products that went into production, the Service Techs would ask Engineering to come down and help with troubleshooting on the new products they weren't familiar with (yet). The sniff test helped quite often. After a bad smell, a closer examination was warranted on a particular part. Then we'd see the chip package was broken, to "let the smoke out".
Blistering on the solder mask on traces was another clue. A symptom, for sure, but not root cause. A fried chip, or solder bridging between chip leads, was the root cause. Later, automated camera-based visual inspection of PCBs (Printed Circuit Boards) helped to spot problems quickly, (solder bridges esp, or chips or diodes put in backwards) before further assembly.
That was back when electronics were mainly built in this country. "Production Yield" was the metric, with scrap cost and t-shoot labor being closely scrutinized. Now, with a lot of low-labor overseas production, scrap cost is handled differently.
Anyway, thanks for the reminder of the "sniff test", before "ATE" (Automated Test Equipment) that probes PCBs with "flying leads" to test PCB and soldering integrity.

Fastb
 
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Thanks for the advice guys.

I already had it totally apart, curiosity. Only took about a half hour to tear down, inspect and re-assemble. I examined all three boards under a binocular loupe and didn't see any signs of where the magic smoke might have leaked from. I've done some trouble shooting and repair over the years, from discrete component vacuum tube stuff, back in the day, to SMD today so I have some, limited, experience. I will say I was impressed with the build quality, heater pad inside, ribbon cables and mini pin connectors all secured with some kind of lacquer (PITA to unplug) and all the boards lacquered as well. Maybe I'll get lucky with an external 12V supply. If that works I may try a regulator board inside and use the PoE lines for power.

I really can't check the cable that started it all very easily. As soon as I realized what was wrong I cut the "offending" RJ off and tossed it.
 
awsum140 said:
Maybe I'll get lucky with an external 12V supply.
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That's what I was going to suggest. Sometimes the POE circuitry can die but leave everything else functional. I've got an older Hikvision like that. It died, got replaced, and then while I was puttering around later figured I'd try a 12v adapter and voila! An extra camera. It's now up high in a garage close to 110v so no major inconvenience for the lack of POE.
 
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I found a 12volt, 1amp, wall wart the other day. My new 5231R-Z should be in by the end of next week. I'll replace the Grandstream at that point and give the wall wart a try on it. Worst case, I'll let out more magic smoke, best case I've got a spare camera. If it does work I'll kludge a method of running power to it on the CAT5 rather than try to locate it near an outlet and deal with an extra cable.
 
You know, I never even considered that. Thanks! Out of curiosity, how big are those things? Grandstream has a rather large RJ45 connector, plus power and a BNC connector. In my case the camera is mounted to a 4" round WP box and it's already pretty tight in there. I could cut off the BNC connector, will never use it anyway, but is still might be a serious challenge to get a splitter in there, too. I guess, worst case, I can swap out the 4" round for a 4" square, but that means drilling a new plate and painting the box and plate to match the "camo" brown I'm using (tree mounted).

 
alastairstevenson said:
just use a PoE splitter to provide the 12v
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awsum140 said:
You know, I never even considered that. Thanks!
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Huh? My previous post:

Fastb said:
You could use a poe splitter to power the cam at the end of that long cable run.....
Click to expand...

As a Newbie, I bought a wifi cam. And learned the hard way that wifi connected cams suck. So I converted it to wired. But wifi cams don't generally support POE. They expect 12v power. But they do have an e-net connector. To use the wifi cam as a wired cam required I run an e-net cable. I ditched the AC cord that powered the wifi cam, and replaced it with a poe Cat 5 cable, to provide a) video and b) power.

My wifi cam is now a wired cam. POE replaces the wifi connection, and the ac cord to the wifi cam power supply. The poe splitter does that.

A conventional 4" round AC outdoor junction box can fit the connections and a POE splitter. I've done that, but it's tight. I haven't done that yet with a purpose-designed cam juntion box.

Fastb
 
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