Failed ICs and components
kylevowen at gmail.com
Wed Feb 11 16:57:25 CST 2015
I am writing my master's thesis on accelerated life testing and would like
to get a collection of parts to decap and experiment on. What prompted my
study is a failed 7474 dual flip-flop in a PDP-8/E. As I later read (on
here, I believe) was that the 7474s seem to fail in higher number than
other 7400-series ICs. Is this because of a design flaw? I'm not sure
(yet), but would like to find out.
More recently, I saw a 680k 2W carbon resistor that read 1.3 meg out of
circuit. As it turns out, it was in a high voltage portion of the circuit,
and I suspect that electromigration caused its failure over time. Many of
you are probably already aware that carbon resistors tend to increase in
value as they age, though there are a few explanations too for that
behavior, as I understand it.
I would like to tie all of this together by researching older accelerated
life testing schemes, examine how those parts actually fared, and see how
current day models might be improved.
If anyone has a collection of dead ICs (preferably those that have died
inexplicably, and not by extreme overvoltage, for instance), I would like
to talk to you about getting a few. If they are 7474s from Texas
Instruments, ca. early 1970s, even better!
Thanks in advance,
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