I can see a water patch in the downstair wall and right on top is the upstair shower area. The shower area is fully tilled. I can see a tiny gap between the wall and floor tiles. I think tile grout will not help to stop this.
Solder mask is usually applied to the copper traces of a printed circuit board (PCB) for protection against oxidation and to prevent solder bridges from forming between closely spaced solder pads. And ALLPCB is a topspeed PCB manufacture in china. Our PCBs are with A–grade military Material and Taiyo Ink. All the PCBs are equipped with Advanced Machin and each board with 100% E-test.