DEC 11/70...

From: Pete Turnbull <>
Date: Mon Apr 6 19:16:36 1998

> > Generally for the old machines we talk about on this list, the chip type
> > code is easy to differentiate from the date code, because of the
> > prevalence of 7400-series TTL chips. Any 74xx or 54xx number will be the
> > chip type, while the other number will be the date code.
> Until you get a machine built in 1974 :-). It's happened to me, it's
> mentioned in 'The Art of Electronics', and it's doubtless happened to
> others here.

Too right. And they don't half misbehave when you mistake the date code for
the logic function :-)

I've got a large boxful of TTL with 74 date codes. Trouble is, I *still* can't
tell which is which on one or two of them, just by looking.

Pete						Peter Turnbull
						Dept. of Computer Science
						University of York
Received on Mon Apr 06 1998 - 19:16:36 BST

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