Path: utzoo!attcan!uunet!cs.utexas.edu!wuarchive!psuvax1!rutgers!bpa!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: One more Amiga RAM question. ;*)
Message-ID: <9917@cbmvax.commodore.com>
Date: 1 Mar 90 17:52:12 GMT
References: <928@orange9.qtp.ufl.edu> <100326@convex.convex.com>
Reply-To: daveh@cbmvax.cbm.commodore.com (Dave Haynie)
Distribution: na
Organization: Commodore, West Chester, PA
Lines: 26

In article <100326@convex.convex.com> swarren@convex.com (Steve Warren) writes:

>I don't know why the chips are soldered in, unless the extra capacitance
>of a socket would be detrimental to the system.  Since zips have leads
>they should be socketable.  Probably it was cheaper and presented less
>quality concerns, since socketed parts have been known to "walk" their
>way out.

Part of the reason is, from a reliability point of view, it's always better
to solder in something that you don't normally have a need of replacing.  So
memories and TTL get soldered in, PALs, Amiga chips, and 8520s get socketed.

The other reason is that, until quite recently, we didn't have a good socket
for the ZIP parts.  DIPs work pretty well with all kinds of standard IC
sockets.  But because of the design, ZIP leads are quite bendable.  If you
put a ZIP many of the standard DIP socket designs (once you maul them into
a zig-zag pattern), you'll find on any given insertion, about 1/2 of the
ZIP's pins will bend up instead of going into the socket.  Special ZIP
sockets don't have this problem, but they also aren't common.

>--Steve

-- 
Dave Haynie Commodore-Amiga (Systems Engineering) "The Crew That Never Rests"
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                    Too much of everything is just enough