Need help with mainboard for AXIS PTZ-camera.

Thread Starter


Joined Feb 14, 2019

Long story short.... I got this faulty mainboard for an AXIS PTZ-camera. It's POE only, and it seems to be something wrong with that portion of the mainboard. The injector turns on and of in half second intervals and this according to the manual suggests short circuit in the receiving end or some other POE failure. I've talked to Axis and they have a hard time sourcing right kind of mainboard, and in the same time it feels like such a waste to just throw what I guess is a pretty competent camera. I believe the on site injector was hit by lightning at some point approximately 3-4 years ago and up til this autumn it was just hanging underneath the beam in the ceiling. We were pretty sure the fault was due to moisture, but it was perfectly dry with not a hint of moisture when I teared it apart.

Now, I've got a basic knowledge regarding different components, I know some measuring techniques and am fairly good at reading components names and find their data sheets, but other than that I'm pretty blank. I've never dived into the depths of electronics so I am wondering if there are some kind people out there with more understanding of this than me who would like to help a less knowing fellow out. Any guidance on where to start would be grately appreciated. My hope and goal is to bypass the POE-section of the mainboard and feed the camera and PTZ-sections directly using an appropriate power supply.

This is what I've gathered so far, please correct me if I'm wrong:


Picture 1: This is the top surface of the PCB, to the right is the POE-part with coils, diodes and some other random things. I believe theres also some kind of filter(black POE+)intended to split the signal from the voltage source.



Picture 2: This is the other side of the PCB. Top right is what I believe to be the stepdown voltage converter circuit. I draw this conclusion from the fact that it is isolated from the rest of the circuitry on this side, its connected to the portion on the top side of the PCB that make up the POE-part. And also I believe those two white things connecting it to the rest of the PCB to be opto-isolators(Pic.3), what those other two smaller ones are idk, but perhaps they are diodes? Also on this side, where the screws is protruding through the PCB is the logic part of the circuit, but I figure I don't have to concern myself with those yet.

Picture 4: Just right next to, and underneath, the daughterboard we find these components depicted in the third picture. I take a wild guess here, but I'm fairly certain these are the driver circuits for the 3 axis motors. All 3 groups are similar in composition and I think I can spot three seperate coils. I haven't looked into this yet.

Various info:

I've measured all diodes I could identify and all check out fine. I've not measured any resistors or caps yet.
My best guess would be that the POE300 is the faulty part.

But to be honest it would be much more fun to be able to bypass this circuit alltogether.

To any OPs reading: If I've put this thread in the wrong category I apologize in advance, please feel free to move it to the right section.

Thanks in advance, and thanks for reading!

Best regards from Norway