When you open the case of a broken device, look for clues for where the problem lies. If you know what to look for, signs of trouble may be obvious.

If you smell a burning smell, that could indicate that a failed component has overheated. Look for any component that smells burnt or is discolored (usually brown or black). That component, or others wired to it, could be the source of the problem.

Also look at the circuit boards themselves. Brown discoloration could be caused by failed, overheating components that you will need to replace.

Check for electrolytic capacitors that are swollen or popped. These are usually small metal cylinders that have deep scribe lines on their tops; when they fail, they may pop open along the scribe lines. Electrolytic fluid may leak out and stain the circuit board.