I didn't realize that Intel made any 2508's. My sense is that they called
their 5-volt parts 8708's. They're the parts that were commonly shipped on
their iSBC-8024's if you ordered a monitor PROM with them.
TI was the one famous for the numbering screwup made by assigning an
industry-standard number to parts that didn't meed the industry standard.
They seem to have reversed output enable and chip select on their parts, not
to mention that their 2716's were multi-voltage parts. Their 2516's were
comparable with the Intel 2716's, however, and MOT made them as well as the
2508's, which I think were half-good 2716's. Since MOT didn't develop
either part, I don't know just offhand which one they pursued. It didn't
matter much, since only the really large ROM arrays used the different
select/enable timings to advantage.
I've enbedded a comment or two below.
Dick
----- Original Message -----
From: allisonp <allisonp_at_world.std.com>
To: <classiccmp_at_classiccmp.org>
Sent: Wednesday, May 24, 2000 3:49 PM
Subject: Re: Altair parts substitutions
> >> Yes, but ... the 5-volt parts were costing on the order of $100 per
> piece.
> >> I bought a bunch for a project and still remember the "sticker-shock,"
> >> though it wasn't any better a year later when I had to buy 2732's. In
> the
> >> latter case, I sold them for $25 each to a west-coast surplus vendor
who
> >> turned around and sold them for $80 each.
>
>
> I paid $11 each for a handful of 2508s in late 1976. A year later 2716s
> were 12$. 2732s were much later and more costly, in 1979(late) I paid
> a whopping 15$ each.
>
> > I find it interesting that after the 2716's were out for a while,
> >and the price had dropped to someplace in the $5-$10 range someplace,
>
>
> The halfgood part 2758 was used on the IMSAI IMP-48 in 1977!
>
> >the intel 2508's were still in the high $30's. This always
> >amused me because there was no difference at all between the
> >Intel 2716 and the 2508 other than the 2508 was a half bad
> >2716. I call that real good sales to take bad parts and get
>
>
> BZZT! 2708 was three voltage and the 2716 was 5V huge
> difference in pin out too.
>
TI's 2716 was a 3 voltage part, too, IIRC. They had a 5Volt-only 2516,
though.
>
> The problem was many vendors were gouging for them and STILL!
>
> Allison
>
>
Received on Wed May 24 2000 - 19:39:33 BST