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From: w_tom on 10 Feb 2006 16:33
Slow multimeter response time is not a problem for identifying
failures. Again, numbers report more than most realize. I posted a
minimum number - 4.87. Notice that power supply spec say it can be
4.75 volts? Good technical reasons explain why that higher minimum
number was provided - which includes how a meter works.

Also probing with a meter can 'fix' a problem that was really a
defective connector. Just another reason why 'shotgunning' is not a
reliable solution. If probing those connectors fixed a problem, then
inspection both of a power supply cable connector and solder joints for
a motherboard connector is recommended.

Yes, a short on power switch line is unlikely. And so are the so
many other problems that could have cause his failure. Bottom line -
long before trying to fix things by shotgunning, a good tech starts and
solves the problem a first time by first collecting facts - while doing
a most minimum number of changes. Yes, probing a connector can cause
changes. But if that probing 'cured' symptoms, then problem may still
remain AND human now knows where to look for it.

Again, numbers from that meter posted here may have resulted in other
useful information. Numbers are always essential to fixing things and
to understanding why failures happen.

BTW, numbers even made it obvious that those aluminum tubes were not
for weapons of mass destruction. Just another example of why failure
happens when numbers are ignored.

PeterD wrote:
> You're unlikely to see anything on a digital meter (response times are
> way too slow), and even an analog meter probably won't show anything
> useful. For this you'd need a scope with storage, with a trigger set
> to fire if the voltages go oout of spec. Not trivial to setup but
> possible. Why bother? Replace the power supply, if that doesn't fix
> it,then the MB is probably toast.
>
> Sure you could have an intermittant short on the power switch lines,
> but that is very unlikely...

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