A-Hunting We Will Go: Signal Tracing and Diagnosis
Now that you have the unit open and ready for diagnosis, it’s time to apply the ideas we’ve been examining and put that oscilloscope to good use. Locating the trouble is the heart of the matter and much of the battle. The general approach is to reduce your variables to eliminate as much circuitry as possible, concentrate on what seems a likely problem area, take some measurements, apply a little logic, and gradually narrow your focus until you reach the bad component.
Where to begin? That depends on what symptoms are being displayed. In order from least functionality to most, here are some good ways to pick a starting point.
As we discussed awhile back, dead means nothing at all ...