Semi-OT: IDE & SATA to USB "dongles"

[Roy J. Tellason]

On Friday 02 June 2006 08:12 pm, Tony Duell wrote:
> > Early 7400-series TTL had the 7450 and 7453 AND-OR-INVERT gates that
> > could be explanded with another 4 inputs via the 7460 dual 4-input
> > expander.  I'd hate to own equipment now that used some of those that
> > required replacement--they must be very difficult to find.
>
> There were at least 2 different expanders, I forget the number of the
> other one.

Have a look at

http://www.classiccmp.org/rtellason/by-generic-number.html

and search for the word "expander" with your browser,  you'll find as many as 
I've been able to find mention of,  and not just TTL either.

> The HP98x0 machines use these gates as the input selectors to the
> bit-serial ALU (and I think to the T register (memory data register)). I
> did have a 74H52 fail in one 9810 (that's an AND-OR gate), fortunately,
> not much of it is used in _that machine_ and I could dead-bug in a
> 74LS51. That wouldn't work in the 9830, or I assume the 9820 (not looked
> at the hardware of that machine yet, next project) as those use rather
> more input sections of the AND-OR gate.

Speaking of 74H stuff,  I have a fair box of chips here that I pulled out of 
the boards of a Burroughs B500 that was scrapped.  Almost all of these are 
"house-numbered".  Does anybody know where there might be a list that crosses 
these over?  I found only one or two that had 74H numbers on them,  and I 
think in maybe one case it had both...

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