At 07:07 PM 1/20/99 +0000, you wrote: 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(a)netsync.net Member of Antique Wireless Association URL: http://www.ggw.org/freenet/a/awa/