From: Adrian Shiner (email@example.com)
Date: Thu Mar 09 2000 - 12:20:01 PST
More "Fud for Thawt"..you don't get dry joints with wire wrap and it was/is
excellent for prototypes if not playing with unnecessary fast edges.
----- Original Message -----
From: "Mayer, Mike" <firstname.lastname@example.org>
Sent: 09 March 2000 14:27
Subject: [SI-LIST] : RE: [IS-LIST] : why .062?
> Wire wrap was not just done by machine. As a student I wire wrapped
> of multibus 1 boards for the University. We used electric wire-wrap guns.
> This was early 1980's.
> Mike Mayer Artesyn Communication Products,
> Senior Hardware Design Engineer Madison, WI
> Mike.Mayer@cp.artesyn.com http://www.artesyn.com/cp
> > -----Original Message-----
> > From: Cusanelli, Tony [mailto:Tony_Cusanelli@mentorg.com]
> > Sent: Thursday, March 09, 2000 5:08 AM
> > To: email@example.com
> > Subject: RE: [SI-LIST] : why .062?
> > A few people asked for the "old guys" to comment on why
> > boards are .062.
> > Back in the dark ages (30 yrs ago) the boards I first
> > designed were merely
> > mechanical devices that supported parts. Connectivity was
> > accomplished via
> > wire-wrap. Parts were heavy and boards had to be thick
> > enough to prevent
> > breakage, but thin enough to carry. 1/16 inch became the
> > right compromise
> > and card guides, standard socket boards and chassis were all
> > designed to fit
> > that thickness.
> > Even with today's lighter parts, tracks are thin and need
> > some support.
> > .032 boards are okay if they are small. Flexing and the pressure from
> > connector insertion/extraction will fracture thin traces.
> > PS - for you young guys - wire wrap was accomplished with a
> > device similar
> > to a hollow drill bit that would wrap 6-8 turns of 30 awg
> > wire around a
> > square or rectangular post. The edges would bite into the
> > wire and make a
> > gas-tight connection that was tested with a pull device
> > (strain gauge). We
> > had some PC boards, but they were mostly 2 and four layer.
> > Draftsmen just
> > could not lay out a board as fast as I could write a wirelist
> > for the wiring
> > machine.
> > Yes now I feel like a dinosaur.
> > Tony
> > -----Original Message-----
> > From: Alex Li [mailto:firstname.lastname@example.org]
> > Sent: Monday, March 06, 2000 9:36 PM
> > To: 'email@example.com'
> > Subject: [SI-LIST] : different 4-layer board Stack up (S-P-G-S) ?
> > Recently I saw a 4-layer mother board with 100 Mhz 128-bit
> > memory bus.
> > This board has unusual signal-power-ground-signal stack up.
> > I talked to
> > one of their engineer for this kind of arrangement. They
> > said since most PC
> > motherboard has several power plane split and on the top
> > level there are a
> > lot of components with pads. they think if they route all the
> > 128-bit memory
> > bus on the back and put it close to ground plane, they have
> > much routing
> > area and this will help to keep the signals clean.
> > This is kind of new idea to me, does anyone see any
> > drawback by this
> > arrangement ? Will this decrease the decoupling caps performance ?
> > Alex
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