4004 and IC history / was Re: Vintage computer photogallery

[Roy J. Tellason]

On Sunday 14 October 2007 16:07, Tony Duell wrote:
> I do remember 7545x parts that were dual 2-input gates with open
> collector outputs that could drive lamps/relays/etc. IIRC AND, NAND, OR,
> NOR gates all existed

Yes,  and I've managed to scrape up data on those.  If I'm not mistaken,  that 
dual floppy drive in the Cromemco we were talking about a bit ago uses a 
bunch of those in there.  (Looking...)  Yup,  here in the "299B Disk Drive" 
manual I spot some 75453 and 75454 in several locations in there.

Those always struck me as extremely handy parts,  I wonder if they're still 
commonly available?

> The only 8-pin TTL chips I (just) rememebr the 7456 ands 7457 (I think)
> which were /50 and /60 counters (desigend to get 1Hz clocks from European
> or US power lines)

Those were LS56 and 57,  or at least that's what's in my parts page,  if there 
were earlier non-LS versions of them I haven't found any data on them.  I 
don't recall ever actually running across those,  but do remember some other 
part number that was a similar package size and functionality.

And speaking of 50 and 60 Hz,  I have this digital clock here that I got 
*real* cheap,  because it has a problem.  it gains a LOT of time every hour.  
Something like 10 minutes,  maybe?  I'm convinced that it's jumpered (or 
something) for 50 Hz line power.  :-)

-- 
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