After we got the phone, we found we can't reboot it no matter what did, so we guess there happens circuit abnormal.
Use the DC power supply to check it, of course, we have opened the ZXW dongle to confirm the point we will check it
After that, we remove the motherboard and feel the hot position with your hands. However, the location of the heating part is not obvious.
The circuit is converted from battery to main power supply through the conversion tube Q2300.
Picture 1
Remove the Q2300 and measure the grounding resistance with the Fluke multimeter to see if there is a short circuit in the battery or the main supply. It is found that there is a short circuit in the main power supply connecting component by value evaluation.
Rosin some rosin on the main power supply connecting component again. The C2331 melts instantly when the single circuit is energized.
Picture 2
It seems that the fault point is here, so we remove the capacitor C2331 by QUICK hot air station and measure the resistance again, the resistance value is normal now, re-install the Q2300 and power-on trigger the iPhone, it can reboot normally.
Here, the iPhone SE repair is over.
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