Importance of a clean chassis

[Einar72]

Working on cell phones, I have found any residue under certain components makes the difference between running or not. With our vintage friends, lifting one leg of a cap or resistor can uncover an amalgam of forgotten flux, cigarette smoke, dust/dander and kitchen grease after you thought you had the board clean, which acts like its own little current path... Hopefully the resistors have a hard, shiny case and can be wiped clean as well.