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.
I don't recall the IC testing company name or location (this was over 17
years ago) but the chips all had a small red paint dot applied after
passing the test. Another, earlier company we used had applied two narrow
white lines across one end of the chip package.
Seems I recall seeing that ETC mark myself a long time ago on some chips
but cannot recall what or where.
Regards, Chris
-- --
Christian Fandt, Electronic/Electrical Historian
Jamestown, NY USA cfandt_at_netsync.net
Member of Antique Wireless Association
URL:
http://www.ggw.org/freenet/a/awa/
Received on Thu Jan 21 1999 - 08:09:45 GMT