Malfunction Phenomenon
The phone can only be charged by one side of the USB cable, but the opposite it does not work.
Trouble Shooting
For the iPhone X No Charging Issue Repair. First, take apart the phone and run the cosmetic inspection of the motherboard first. And the cosmetic is just fine, there is no deformation or water damaged trace.
After checking the cosmetic, if you have a dock flex cable by your side. You can also try to change another dock flex cable to have a test.
Then check the DOCK connector J6400 with a multimeter, the measured diode value of pin 16 is 0, which is abnormal. From the circuit diagram, pin 16 of J6400 is connected with pin A5 of U6400(USB IC) by way of C6411, FL6411.
Above is the block diagram for reference.
You can also track by the bitmap or schematic to know the connected relevant chips.
So we can try to remove the C6411, then we measured the diode value of pin 16 again, the value is back to normal.
So we can conclude that the fault is related to C6411. Then assemble back the two layers of the motherboard, the issue resolved.
iPhone X Motherboard Repair Course