Why you need rework the PCB of MPPS V18 china clone?
Because there are two versions of Mpps china clone. One comes with missing components and different resistors are installed with red marks below：
Working mpps v18 clone should be like this:
So, some cheap MPPS china need rework.
For the mpps above:
D1 = PESD1CAN ESD protection
U4 = PRTR5V0U2X
Zoom on it and see what’s missing.
You must solder K line driver in empty U8 place not in U12 where is Lm2903
this schematic if it also helps
In summary, not all china good! and you get what you paid for.
Good luck with china clones.