I ran into an interesting case a few days ago, I was wondering how many of you have run into the same deal.
A good friend of mine that I play guitar with occasionally called me because his 1-year-old Marshall AS100D had the second channel cut in and out, would die completely when he hit the phase switch, etc., etc. Of course, this is 3 days before a gig.
I guessed that maybe either there was a bad solder joint somewhere, or an intermittent ground. Now, this is a solid state amp, with 3 different boards. This channel lives in the lower front board along with the mic channel and the aux inputs. So, I go ahead, go to his place, take the amp apart, pull the board, and the solder joints look good, but there seems to be some kind of muck between a bunch of the switch contacts. Now, how did muck get to the BOTTOM of a circuit board, inside a closed enclosure? I assume that it must have been flux that wasn't properly cleaned off the board when it was manufactured - who knows why it took a year's worth of use to show up (heat made it flow?).
Contact cleaner, a fine brush, and ten minutes later - voila.. brand new amp. 3 cents worth of cleaner took care a huge bill for fixing an amp - crazy.
Small details that make a $700 amp a waste of space.
