So digging into my other brand ip ptz camera I thought it would be an easy repair when I connected it to one of my older POE NVRs and stopped working on POE.. well today thought I would take it down and take a look.. seems the issue I thought it might be isn't. Now have to find someone with like ptz that would be willing to take there's apart and tell me what the chip is so I can order one to repair this. The camera still works if I power with 12v but main reason to have POE is so we can have just Ethernet cable ran to install site and means I don't have power source at normal camera location.
The Amcrest cameras have much better circuit and offers better protection to the circuit.
Seeing this is a Ver B circuit board they must have already had some issues with the camera dying already.
Can you spot the damaged area? Had to resize image the normal size was to large for site upload..
20240408_143951_resized.jpg (1.37 MiB) Viewed 496 times
Once and if I ever find out what the chip is lol. I will post some still shots of the repair. First one is already there with the Chip in place. With the removal just need to use hot air with long bent tip to get the heat down to that chip area. I am not sure if it is glued my guess is that it might be only soldered with a center pad either way it shouldn't be to much of a pain. Then will clean the old solder off add some fresh solder and then heat the area and set the chip. Or if that seems to hard because of the Transformer there then I will use solder paste on the pads to set the chip either way it will be a 1 or 2 try.. I will know more when I go to take the chip off if I am going solder paste or normal placement..
Don't know if you notice or not, But the Reflow and Wave are both same direction. You can tell this PCB was designed for mass production in mind with all the test points and solder mask.
So far i am not sure what it is. I would need to do a deep dive into the PCB to find out where each part is going to the chip to know for sure what it might be for sure. Even then 50/50.. So far only thing that I have found that might be what was used is a Ti part TPS23754 However would have to look over the board. I have installed it back in the camera and have placed it at a different location for now with Power close by so I could use 12v power supply.
Maybe one of these days I'll get to the power board problem from that cool little HDCVI Dahua PTZ that died straight out of the box. Unfortunately my surface mount troubleshooting skills leave much to be desired!
Here is an idea, Get some Alcohol and test the voltage input area of the PCB. Once you find what Sizzles report it back Keep in mind that it should be 99% pure Isopropyl Alcohol (IPA). Where there are some that use other keep in mind that not knowing what you are doing can cause more damage then good..
Why does Alcohol work to find a short? Mainly because the short will heat up and cause it to evap faster then normal. IF the fault is caused by an open this method won't help. So double check any fuses and make sure there is no open fuses. Not everyone has 1amp buss wire but if you happen to have some and the fuse is open you can use the buss wire for a temp fuse for testing out the rest of the circuit. Just remember there was a reason a fuse was blown. So some down line testing after the fact is good to try and find a short. Diodes and fuses are designed to protect the circuit it is on line with. They work as reverse polarity, help with voltage spikes or transient voltage from damaging other components. Most diodes are used for current flow control but as I pointed out they also play a protective role in circuits.
Having a good muli meter with diode tester is good. Keep in mind that testing diodes can be tricky when it comes to TVS, Schottky, LEDs, and or Zener diodes, so understanding that some testing require specialized equipment. These would be things like curve tracers and Oscilloscope can help with most diode testing. The specialized testers would provide precise measurements.
If you find a short divide the circuit into sections and test each section to help isolate the area where the short occurs. Some times you will need to remove different components one by one and test the circuit after each disconnection to see if the short persists.
