reg + reference
in [Design]
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From: krw on 31 Mar 2010 18:55 On Wed, 31 Mar 2010 05:24:45 -0700, "JosephKK"<quiettechblue(a)yahoo.com> wrote: >On Sat, 27 Mar 2010 08:49:16 -0700, Joerg <invalid(a)invalid.invalid> wrote: > >>Nico Coesel wrote: >>> Joerg <invalid(a)invalid.invalid> wrote: >>> >>>> It's like press-fit where I sat in a meting where a company pitched it >>>> to a client. Tappa-di-tap went my calculator. "I calculated that 3 out >>>> of all the contacts will be open. Can you tell us which ones those will >>>> be?". The meeting and the sales pitch ended that instant ... >>> >>> Sorry but that must be some calculating error on your side. All PABXes >>> I've seen had press-fit backplanes for a very good reason >>> (reliability). But just like soldering and crimping connections >>> mounting press-fit is something that needs to be done right. >>> >> >>On the first series it had been done by the pros. Sorry, but my >>experience with pressfit is not positive. Not as bad as with wire-wrap >>but close. > >Hmm. My experience with wire-wrap has been uniformly good. Also like >soldering and crimping, it must be done right. 30+ years ago i was certified >for solder, wire-wrap and crimp. WireWrap was used in a *lot* of places where reliability was the primary importance. Mainframe backplanes were all wire-wrapped at one time.
From: markp on 31 Mar 2010 20:55 <krw(a)att.bizzzzzzzzzzzz> wrote in message news:sjk7r55f3jsmk5e6fc7e07h38ib2b3vnvv(a)4ax.com... > On Wed, 31 Mar 2010 05:24:45 -0700, "JosephKK"<quiettechblue(a)yahoo.com> > wrote: > >>On Sat, 27 Mar 2010 08:49:16 -0700, Joerg <invalid(a)invalid.invalid> wrote: >> >>>Nico Coesel wrote: >>>> Joerg <invalid(a)invalid.invalid> wrote: >>>> >>>>> It's like press-fit where I sat in a meting where a company pitched it >>>>> to a client. Tappa-di-tap went my calculator. "I calculated that 3 out >>>>> of all the contacts will be open. Can you tell us which ones those >>>>> will >>>>> be?". The meeting and the sales pitch ended that instant ... >>>> >>>> Sorry but that must be some calculating error on your side. All PABXes >>>> I've seen had press-fit backplanes for a very good reason >>>> (reliability). But just like soldering and crimping connections >>>> mounting press-fit is something that needs to be done right. >>>> >>> >>>On the first series it had been done by the pros. Sorry, but my >>>experience with pressfit is not positive. Not as bad as with wire-wrap >>>but close. >> >>Hmm. My experience with wire-wrap has been uniformly good. Also like >>soldering and crimping, it must be done right. 30+ years ago i was >>certified >>for solder, wire-wrap and crimp. > > WireWrap was used in a *lot* of places where reliability was the primary > importance. Mainframe backplanes were all wire-wrapped at one time. > I worked for a company that made defense equipment. A lot of modifications made by the wiremen were wire-wrapped. The key is getting the technique right, and specifically avoiding strain or movement of the wires. They were all laid out very neatly and securely, and the results highly reliable. Mark.
From: John Larkin on 31 Mar 2010 21:34 On Wed, 31 Mar 2010 17:55:20 -0500, "krw(a)att.bizzzzzzzzzzzz" <krw(a)att.bizzzzzzzzzzzz> wrote: >On Wed, 31 Mar 2010 05:24:45 -0700, "JosephKK"<quiettechblue(a)yahoo.com> wrote: > >>On Sat, 27 Mar 2010 08:49:16 -0700, Joerg <invalid(a)invalid.invalid> wrote: >> >>>Nico Coesel wrote: >>>> Joerg <invalid(a)invalid.invalid> wrote: >>>> >>>>> It's like press-fit where I sat in a meting where a company pitched it >>>>> to a client. Tappa-di-tap went my calculator. "I calculated that 3 out >>>>> of all the contacts will be open. Can you tell us which ones those will >>>>> be?". The meeting and the sales pitch ended that instant ... >>>> >>>> Sorry but that must be some calculating error on your side. All PABXes >>>> I've seen had press-fit backplanes for a very good reason >>>> (reliability). But just like soldering and crimping connections >>>> mounting press-fit is something that needs to be done right. >>>> >>> >>>On the first series it had been done by the pros. Sorry, but my >>>experience with pressfit is not positive. Not as bad as with wire-wrap >>>but close. >> >>Hmm. My experience with wire-wrap has been uniformly good. Also like >>soldering and crimping, it must be done right. 30+ years ago i was certified >>for solder, wire-wrap and crimp. > >WireWrap was used in a *lot* of places where reliability was the primary >importance. Mainframe backplanes were all wire-wrapped at one time. > DEC loved wire-wrap, but as logic got faster the impedance and crosstalk issues became untenable. PCBs were cheaper anyhow. John
From: Tim Williams on 31 Mar 2010 23:14 "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:2vt7r5p5qcrd78neuabj8b9gu837pecbt2(a)4ax.com... > DEC loved wire-wrap, but as logic got faster the impedance and > crosstalk issues became untenable. PCBs were cheaper anyhow. Ironically, ECL came out before TTL. They routed those with twisted pair. Automated twisted pair wire wrapping machines -- awesome tech! Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms
From: krw on 31 Mar 2010 23:48
On Wed, 31 Mar 2010 18:34:57 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Wed, 31 Mar 2010 17:55:20 -0500, "krw(a)att.bizzzzzzzzzzzz" ><krw(a)att.bizzzzzzzzzzzz> wrote: > >>On Wed, 31 Mar 2010 05:24:45 -0700, "JosephKK"<quiettechblue(a)yahoo.com> wrote: >> >>>On Sat, 27 Mar 2010 08:49:16 -0700, Joerg <invalid(a)invalid.invalid> wrote: >>> >>>>Nico Coesel wrote: >>>>> Joerg <invalid(a)invalid.invalid> wrote: >>>>> >>>>>> It's like press-fit where I sat in a meting where a company pitched it >>>>>> to a client. Tappa-di-tap went my calculator. "I calculated that 3 out >>>>>> of all the contacts will be open. Can you tell us which ones those will >>>>>> be?". The meeting and the sales pitch ended that instant ... >>>>> >>>>> Sorry but that must be some calculating error on your side. All PABXes >>>>> I've seen had press-fit backplanes for a very good reason >>>>> (reliability). But just like soldering and crimping connections >>>>> mounting press-fit is something that needs to be done right. >>>>> >>>> >>>>On the first series it had been done by the pros. Sorry, but my >>>>experience with pressfit is not positive. Not as bad as with wire-wrap >>>>but close. >>> >>>Hmm. My experience with wire-wrap has been uniformly good. Also like >>>soldering and crimping, it must be done right. 30+ years ago i was certified >>>for solder, wire-wrap and crimp. >> >>WireWrap was used in a *lot* of places where reliability was the primary >>importance. Mainframe backplanes were all wire-wrapped at one time. >> > >DEC loved wire-wrap, but as logic got faster the impedance and >crosstalk issues became untenable. PCBs were cheaper anyhow. IBM used it too. PCBs were cheaper for cards but the backplanes were still wirewrapped. As the backplanes went printed, WW was still used for overflows. Since vias were only permissible on .125" centers there were a *lot* of overflows - even in eight layers. |