Hi,
it's a PoE camera and it stopped working. Using thermal image I identified failing component U22 marked as 16AF which seems to be buck convertor TI https://www.alldatasheet.net/datashe...62569DBVR.html. I took it out and It is inteed shorted on the output. However, after I took it out, the resistance between the output pads (on the board) still shows 190ohm, is that bit low?
Another issue is, seems to me I must be missing one of the tiny resistors R810 that should make up the voltage devider for the buck convertor. Honestly I did this months ago, I cannot remember if I was using hot air (to take 16AF out) or not. Could that convertor even work without that resistor? The pads look pretty clean there, I wouldn't have guessed there was a component soldered there originally. For completeness, the other resistor in the devider R809 is 10k.
It's not very well visible, but I checked and R810 pads are indeed connecting between FB and GND on the buck convertor, while R809 is connecting between FB and inductor L12 (on the output the buck converter).
There are 2 other identical buck converters on the board, but they seem to have different value resistors, probably setup for different output voltage.
I tried my best with the picture, but it's not great, sorry. I marked the place where the buck convertor was with a red dot.
Thanks
it's a PoE camera and it stopped working. Using thermal image I identified failing component U22 marked as 16AF which seems to be buck convertor TI https://www.alldatasheet.net/datashe...62569DBVR.html. I took it out and It is inteed shorted on the output. However, after I took it out, the resistance between the output pads (on the board) still shows 190ohm, is that bit low?
Another issue is, seems to me I must be missing one of the tiny resistors R810 that should make up the voltage devider for the buck convertor. Honestly I did this months ago, I cannot remember if I was using hot air (to take 16AF out) or not. Could that convertor even work without that resistor? The pads look pretty clean there, I wouldn't have guessed there was a component soldered there originally. For completeness, the other resistor in the devider R809 is 10k.
It's not very well visible, but I checked and R810 pads are indeed connecting between FB and GND on the buck convertor, while R809 is connecting between FB and inductor L12 (on the output the buck converter).
There are 2 other identical buck converters on the board, but they seem to have different value resistors, probably setup for different output voltage.
I tried my best with the picture, but it's not great, sorry. I marked the place where the buck convertor was with a red dot.
Thanks
