Ink stamp on 1970s IC's.

From: Dave Dameron <>
Date: Thu Jan 21 09:55:36 1999

At 09:09 AM 1/21/99 -0500, Chris wrote:
>At 07:07 PM 1/20/99 +0000, you wrote:
>>Hi all,
>>I have seen several plastic DIP IC's from the 1970's have a white ink stamp
>>on them that
>>say something like "ETC 4" on them. (Your number may vary) Most are Intel
>>RAM's, but some are Signetics or National TTL. Before I have seen them on
>>chips on boards, but have now bought a bunch of IC's new in tubes which also
>>have this stamp.
>>Has anyone else seen this and know what it means?
>This is probably a mark from a company who tested the IC. Back in those
>days, third-party outfits would often "burn-in" ICs before the company who
>purchased them received them. The ICs were put under correct the correct
>supply voltages and left in a closed chamber for many hours (24, 36, 72? It
>varied.) Some IC distributors offered this extra cost service. It helped
>make sure the chip would not fail prematurely when the end item was in
>customer's hands. At Bausch & Lomb, when my ex-employer was still a
>division of them, we had even the TTL and old RTL/DTL chips burned-in, not
>just the expensive RAM, CPUs, etc. Some products from other B&L divisions
>were used in medical labs and opthalmic labs and needed to be quite
>reliable. Our division's products, used in an industrial environment,
>benefited very nicely from tested ICs.
Thanks. This is what I guessed, and means the IC's have seen some third
party testing company. Some 2102 rams that I had bought "new" in tubes and
some from Godbout (S-100 memory cards) have the "ETC" stamp, so their
supplier had already gotten them this way, vs. direct from Intel.
Have seen the red enamel dots on IC packages as well, usually TTL.
Received on Thu Jan 21 1999 - 09:55:36 GMT

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