[AllanG]

Have anybody ever hear about dendrites? Google about it, it will worth.






It's a "disease" that attacks PCB,s mostly caused by the use of some types of flux. The most the PCB's are exposed to high levels of moisture in the air, the quicker the problem arrives.

Almost all RX and TX modules I saw, have signs of use of inorganic flux. They should always be cleaned with distillate water, not alcohol or acetone which only dilutes the flux and spread it in a tiny film along all the board. When you use alcohol or similar flux dissolvers, always wash the assembled boards with distillate water, and fully dry them before use.

Wow that's amazing, Werk_AG!! Unfortunately the best lens I have for my camera is a 60mm Macro that I used to take the photo of the wifi module. I'm sure if I had a more powerful lens I would see something like that first one of the two pads.

Yes, the tx board that the wifi module is mounted on is certainly open to moist air, I've described the circumstances in my reply above to Mark (Wizza). Of course in normal operation in a weatherproof and sealed enclosure, this kind of situation is unlikely to arise but it's good to know the potential problems that can arise. Personally, in future I'm going to clean and check carefully the wifi modules *before* I use them...

Allan.