i was folow developing of case you got....i am hobbist to and from my
experience i can tell that malfunctions caused by "cold solder" are most
dificult problems to solve...especiali when there is some random states of
working and it doesnt working...and again...and again...but you cant see
it where does it happening...



They're one of the most common faults as well, many times more extensive
failures start out as cold solder joints. Often prodding or flexing the
board will make them more obvious.