HikVision camera troubleshooting

[Adenitz]

Hello to all,

I have a very similar problem to what is already described herein this thread.
The model is DS—2D2123. In normal operation the camera is forseen to operate on PoE. There is additional connector 12VDC. There was a power surge caused by a short circuit on nearby power line 230VAC cable for light was next to ethernet cable, so Camer has no power after that. I have found one protection diode short circuited to ground and remove it. That did not solve the problem. However if I use 12VDC connector and connect to PSU, it seems that camera works, there is a LED green flashing. However, I didn‘t connect ethernet cable, because I know there is 48VDc in it, so I didn‘t test it because I am not sure if it can inflict damage on the DVR device.
So my first question is should I try to connect ethernet cable to the DVR to test the camera or perhaps to identify and cut 48VDC first?

I hope someone can provide an useful advice.

Thank you.

[CapLeaker]

As stj already said, these rectifier diodes aren't there to rectify AC. These diodes are there to make sure the DC always has the same polarity to the board. Someone could crimp a RJ45 wrong, etc. The protection diode is probably some sort of a TVS.
Just put a normal ethernet cable to the camera and plug it and the NVR into a switch so both are on the same network. Config the NVR to see the camera on the "internet" side. done.

[CapLeaker]

I'd protect the NVR and buy a POE switch like TP-Link and play with the camera on there. If something does go sour, that TP link switch will turn the power off. By right's the NVR should do the same, but there are no guarantees.

[Adenitz]

Hi CapLeaker, that is very good idea. I will order one used PoE switch, it can serve even as "PSU" for my IP cameras.

In the meantime, I did some troubleshooting and would like to hear your advice. Since camera can be both supplied by PoE and 12V DC I guess this part of input PSU is somewhat "redundant".

Please have a look at the attached picture.

I have found one ESD/TVS protection diode shorted to ground and this diode is removed. This diode has label: B58C2, so I assumed it is BV-SMBJ58C2H diode. This diode is removed from the board.
Now, very near to the connector there are two Vishay MB6S-E3/80 rectifier diode. I assume these diodes will rectify input voltage from the connector. This part is somewhat confusing since PoE 48V should be DC and not AC, but in any case, I have found that one of these two diodes have some of the diodes shorted.

One diode package MB6S-E3/80 per datasheet contains 4 diodes.
So I know for sure that in one diode package I have a short circuit between "-" side and "~" side. So this clearly needs to be changed.

So my question is the following:
Is it possible to solve this problem using the following steps:
1. move protection diode B58C2 from its current position to the position where other B59C2 got shorted
2. remove shorted diode rectifier package and in its position move correctly functioning rectifier package

My assumption is that one protection diode was on PoE and other is on 12 VDC and also, one rectifier diode package is used for 12 VDC while other is for PoE.
I'm not sure whether both MB6S-E3/80 are needed for PoE

Thank you.


P.S. I have just realized that these diode packages are not redundant. + and - sides are indeed in parallel, but not "~" sides. In fact when follow 12VDC wires that go into connector, they are not connected to diode packages.

So I guess I'll have to order a new diode package MB6S-E3/80 and find someone skillful not to damage plastic connector while soldering. I just hoped I could use this one correct diode package instead of two.

[stj]

even if POE is dc, using a rectifier will correct the polarity if the wires are crossed over.
i used to put rectifiers into kids toys incase they plugged the wrong psu in.

[Adenitz]

Thanks for reply.
I'd like to try one more thing. NVR is supplying power to the camera via ethernet wires (POE). I can see according to the pinout that POE DC+ are wires 4 and 5 while DC- are wires 7 and 8. Therefore, I will cut these wires just in case, and use 12 VDC separate camera supply. This should work if the rest of the mainboard is OK. This way only data wires will have actual contact to the port on the NVR/DVR device.

This way I think, I can safely test whether mainboard survived or not. It shows some signs of life when connected to 12 VDC separately, but no signs whatsoever if connected to the PoE port.

[CapLeaker]

As stj already said, these rectifier diodes aren't there to rectify AC. These diodes are there to make sure the DC always has the same polarity to the board. Someone could crimp a RJ45 wrong, etc. The protection diode is probably some sort of a TVS.
Just put a normal ethernet cable to the camera and plug it and the NVR into a switch so both are on the same network. Config the NVR to see the camera on the "internet" side. done.

[Adenitz]

Thank you CapLeaker, this is the way I'm going.