Re: ECB backplane, revised

[lynchaj <lyn...@yahoo.com>]

On Jul 17, 8:15 pm, lynchaj <lyn...@yahoo.com> wrote:
> Hi Jack,
> I am working on the ECB backplane tonight.  I think I've made some
> real progress on it.  The good news is that we'll keep the 2 layer
> PCB.
>
> All pins will be routed and there will be pads for a switch or jumper
> depending on what the builder wants.
>
> I will probably be a little less communicative while working on the
> backplane.  The autorouter runs on my main system and it needs to be
> left alone.
>
> When I send it for manufacturing, I will specify the heavier PCB
> material and traces if I can.
>
> Thanks and have a nice day!
>
> Andrew Lynch
>
> On Jul 16, 10:23 pm, "Jack Rubin" <jack....@ameritech.net> wrote:
>
>
>
> > Andrew,
>
> > Reduced cost may not be the only reason to avoid a multilayer motherboard.
> > As I'm sure you know, a multilayer board will often have generous ground
> > planes for reduced signal-to-signal interference and greater noise immunity,
> > especially if people want to overclock their systems.
> > I really defer to the EE pros here but just want to raise the question.
> > Howard and Allison (and probably others) have real-world experience building
> > these systems and can provide better guidance.
>
> > In addition, going to a thicker board can be very advantageous for a
> > motherboard by providing greater physical stability and resistance to
> > twisting (with resulting stress to traces and solder connections) as boards
> > are removed and inserted.
>
> > Jack
> > KC9HVE but hardly anybody's Elmer!
>
> > > -----Original Message-----
> > > From: n8...@googlegroups.com [mailto:n8...@googlegroups.com]
> > > On Behalf Of lynchaj
> > > Sent: Wednesday, July 16, 2008 8:43 PM
> > > To: N8VEM
> > > Subject: [N8VEM: 329] ECB backplane, revised
>
> > > Hi All,
>
> > > Well, some good news.  My new approach on the ECB backplane
> > > seems to be working.  It is awful slow manual work but is
> > > creeping along.  All the traces are linked into one large
> > > pattern a bit like knitting.
>
> > > I posted a PDF of the progress so far.  Try not to laugh  :-)
>
> > > It is obviously pretty rough still but the intent of this
> > > version is to proof out the trace pattern to allow all 96
> > > pins in the connectors to be connected.  Using a 4 layer PCB,
> > > this would be trivial and the autorouter could handle it no problem.
>
> > > However, using a 2 layer PCB this backplace routing gets a
> > > lot more complicated.  The problem with 4 layer PCBs is they
> > > triple or quadruple the price so using 2 layer PCBs is the
> > > key to keeping costs down.
>
> > > The SBC went through several complete iterations before I
> > > settled on the final version and even that still has its
> > > problems.  Don't worry, you'll see this PCB design gyrate for
> > > a while longer too.  :-)
>
> > > Please let me know if you have any comments or questions.  
> > > Thanks and have a nice day!
>
> > > Andrew Lynch > No virus found in this incoming message.
> > > Checked by AVG -http://www.avg.com
> > > Version: 8.0.138 / Virus Database: 270.5.0/1556 - Release
> > > Date: 7/16/2008 4:56 PM- Hide quoted text -
>
> > - Show quoted text -- Hide quoted text -
>
> - Show quoted text -

Hi All,
I uploaded a new version of the ECB backplane.  I think you'll agree
it is looking much better.

Please review and send me your comments.  I am getting ready to order
a batch in the not to distant future so I would appreciate hearing
from you!

Thanks and have a nice day!

Andrew Lynch