I connected a camera to 12V and POE at the same time. Now only 12V works. Help me fix it!

E

enricol

n3wb
Dec 16, 2019
20
8
Italy
Hi guys. I don't know how it could happen: I broke an IP camera by connecting both to 12V and POE at the same time. I was distracted and didn't notice that both were connected. Now only 12V works.

A bit of context: it's an IESS camera, model 72138

1783115287872.png
It's connected to an IESS POE NVR. If I connect the camera to the NVR POE port, the yellow led on the NVR port doesn't even light up. But if I also connect the 12V, then the yellow led starts blinking an the camera comes back to life.

I opened the camera to inspect the board. With some luck, I found a shorted SMD resistor 920 ohm and I replaced it with one 1000 ohm I had lying around

1783116595384.jpeg1783116657826.jpeg

Unfortunately that didn't do the trick. What should I check next? Do you have any suggestions?

I'm sorry if I missed some details. It's actually my dad working on the pcb. I'm just reporting here the progress.

Thanks to anybody that will try to help!
 
Check the three legged component next to the formerly-shorted resistor. It's most likely a voltage regulator.
 
I don't know about IESS cameras. Every one of the Dahua cameras I've opened up has a diode that's connected first thing to the 12 volt input, serving as both reverse polarity protection and to keep the DC from the poe circuit from flowing out of the DC input. The D15 on your board could be that component, easy enough to see by ohming it to the positive side of the DC power connector. That diode of course wouldn't protect the poe circuit from what comes into the 12 volt input, I'm just proposing it as an alternate starting point for circuit tracing. The newer Dahua cameras brag as a feature that they can be powered by both methods for power redundancy, so they would have something to protect the poe circuit output.

I'm assuming the chip right next to D15 is the network interface input. Maybe it's as simple as the poe pickoff function having been fried? Just thinking out loud rather than actually knowing much about it.
 
Last edited:
  • Like
Reactions: VorlonFrog
enricol said:
Thanks for all the answers!

I ended up just using one of those adapters that take the POE ethernet and transform it to DATA ethernet + 12V
Click to expand...
A "POE splitter".....good option! Are you able to protect the splitter from the weather and use dielectric grease on the connections? :cool:
 
  • Like
Reactions: looney2ns
You must log in or register to reply here.
Top Bottom