[sdiy] what do cold joints look like?

[ElmacacoX at aol.com]

Hi everybody.

my csq 100 is having some sort of timing trouble (when a sequence is looped, 
it slows down considerably)

upon opening it up, I see lots of the solder joints are a dark thundercloud 
grey color.

what does this mean?  are these cold joints?  why do they change color?

who wants to be my Mr. Wizard? (he he)

thanks

Ed