I'll bet the input mode switch (S1) is not a sealed switch and the contamination occurred during the soldering process, be it by hand or wave soldering. Flux residue is the most likely cause. Seen this many times.
Too bad you had these problems, hope you have smooth sailing now on.
__________________
System: ML:5206,5302 Serafino's Nordost Lumin U1 RM15
|