2 Dec
2005
2 Dec
'05
3:14 p.m.
After some time of carefully showing the system test
fellow a number of scope signals and carefully explaining
the reasons I was looking at particular locations,
I happened to glance at his notes. It went something
like this:
D3, D5, D8, D20, D21
There were no symptoms and nothing of what I showed him
about scope information. I soon realized that he was
ARGH!!!
There is a saying in England 'Measure twuice and cut once', menaing it's
better to re-check a measurement than ruin some metal/wood/whatever by
cutting it too short. I would like to propse a new version
'Measure twice and solder once'
meaning you should make measurements, think about them, and _only then_
start changing compoennts.
just interested in a list of parts that I indicated as
causing problems and wasn't even paying attention to
anything else I was doing.
The worst part was that since this was a one time
parts mix up, it probably would never happen again
so that his list was virtually worthless. I told
This is actually another problem with those lists of stock faults. If a
fault is caused by an under-rated componet, it's likely that, after a
couple of years, all have failed and been replaced (hopefully with a
better-rated version). And therefore if the same symptoms occur in the
future, the cause could well be soemthing totally different.
-tony