3 Sep
2009
3 Sep
'09
4:05 p.m.
Tony Duell wrote:
HP made a couple of other devices that I don't own
and could never see
the point of. One was the 'signature analyser' which will tell you if a
logic signal differes from the correct version (well, provided you have a
'correct version' to also test) but won't tell you _how_ it differs. So
actually finding the fault doesn't seem to be any easier.
Of course it makes finding the fault easier. The general approach is
that if the signature at an output signal of a chip is bad, but the
signatures at all of the input signals to that chip are good, then the
chip is almost certainly bad. You find a bad signature, and work your
way upstream.
The purpose is to make it possible for technicians with only basic
electronics knowledge to diagnose a failure, without requiring them to
have intimate knowledge of how the product works. In many cases the
technician can repair the fault, but if not, then it can be escalated to
a more knowledgeable technician or engineer. (Or simply scrapped.)
Obviously signature analysis is going to be of limited or no utility to
someone like yourself.
Eric