The locating and resolution of faults can often seem a hopeless
task. However once the fault is proven there must be a cause
and the process is one of elimination. However there are two
additional caveats which should be remembered.
Many an investigation has proceeded to an impasse and hence
frustrations through the investigator missing out some obvious
check or test or assuming that someone else has done it.
Always be aware that there may be an obvious solution, which
has been overlooked. This may be as simple as a blown fuse
on a card or unchecked component never known to have failed
Nothing can be discarded from the investigation until it has
been proven to be unrelated.
Remember double-checking will do no harm.
When searching for the cause of a fault the greatest source
of information you will have are the users of the system.
Use them. Ask questions. Listen to their descriptions and
check them. What sounds like a mistaken term or phrase may
lead to new avenues of investigation which would not have
Above all do not disregard anything until it has been properly
eliminated from the search.