5 Sep
2009
5 Sep
'09
12:04 a.m.
Tony Duell wrote:
Sure, the service manuals often give the signatures.
So you connect up
the signature analyser (start/stop/clock leads) and stick the probe on a
given point. If the signature agrees with the one in the manual, fine. If
it doesn't, then what? OK, there's a fault, but in a lot of complicated
systesm, particularly if state-machine or microprocessor based, a fault
just about anywherre will corrupt all the signatures, So how do you
determine which device has actually failed?
If a simple fault really makes all or even most of the signatures wrong,
then the test engineers didn't design the test mode(s) of the product
properly. I haven't observed that problem with HP or Atari products
that have documented signatures.
Eric