Failed ICs and components

Marc Verdiell marc.verdiell at
Sat Feb 14 02:04:28 CST 2015

Mattis Lind from this forum sent me some failed National Semiconductor 74xx
series, plastic encapsulated. These were from an HP 98xx series calculator I
believe. He noticed than when they failed they failed open. I failed myself
to have the local National Semi people interested in looking at them, and I
just did some XRays to find out if something obvious had happened to the
wire bonds. Nothing we could see, but we didn't take enough close ups. I
want to take a look again, and if I don't find anything could send them on
to you if Mattis is OK with it.

> Darn! That sounded like a good collection. Alas, I know I haven't kept
> every bad IC either (except that one from the PDP-8/E...not really sure
> until now, I guess). But if you do find them, I could certainly use them.

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