28 Sep
2002
28 Sep
'02
2:46 p.m.
This would be much much safer for the machine that any unsldering,
however skilled. Unsoldering
WILL greatly reduce the service life of chips, old or new. The older,
the greater this effect, but its
very measurable even with the newest parts made.
Using a crowbar is an excellent suggestion really, if your
super-concerned about rare chips, a clip-on crowbar will
trip faster than TTL devices are dammaged by an over-voltage condition.
Patrick Finnegan wrote:
OK, so if you're all worried about dead voltage
regulators, why not just
put a crowbar on a board when you first power it up, and make sure that it
doesn't fire? Doing this one board at a time seems reasonable. If the
crowbar doesn't fire, and you can measure 5V+- output from each regulator
as it's powered up, you should be just fine to do a test without the
crowbars.
Of course, since it's a linear supply, you could (and probably should)
test it first under no load and make sure you get a good +8V or so output,
with good filtering. Then, you aught to be able to try powering the
boards up one-at-a-time with crowbars on them, to make sure everything is
OK.
-- Pat