S-100 backplane board spacing Al Kossow aek <mailto:cctalk%40classiccmp.org?Subject=S-100%20backplane%20board%20spacing& In-Reply-To=> at bitsavers.org Fri Feb 6 09:13:35 CST 2009 * Previous message: S-100 backplane board spacing <http://classiccmp.org/pipermail/cctalk/2009-February/268634.html> * Next message: Some Microtek MICE documentation <http://classiccmp.org/pipermail/cctalk/2009-February/268620.html> * Messages sorted by: [ date ] <http://classiccmp.org/pipermail/cctalk/2009-February/date.html#268616> [ thread ] <http://classiccmp.org/pipermail/cctalk/2009-February/thread.html#268616> [ <http://classiccmp.org/pipermail/cctalk/2009-February/subject.html#268616> subject ] [ author ] <http://classiccmp.org/pipermail/cctalk/2009-February/author.html#268616> _____ You also need to specify the spacing of the circuit and component side pins on the connector for your backplane. There are at least two different spacings that were used. Most were the wider style, early MITS backplanes had closer spacing. _____ * Previous message: S-100 backplane board spacing <http://classiccmp.org/pipermail/cctalk/2009-February/268634.html> * Next message: Some Microtek MICE documentation <http://classiccmp.org/pipermail/cctalk/2009-February/268620.html> * Messages sorted by: [ date ] <http://classiccmp.org/pipermail/cctalk/2009-February/date.html#268616> [ thread ] <http://classiccmp.org/pipermail/cctalk/2009-February/thread.html#268616> [ <http://classiccmp.org/pipermail/cctalk/2009-February/subject.html#268616> subject ] [ author ] <http://classiccmp.org/pipermail/cctalk/2009-February/author.html#268616> _____ More information <http://www.classiccmp.org/mailman/listinfo/cctalk> about the cctalk mailing list _____ -----REPLY----- Hi! Thanks Al! My question is really what are the commonly accepted standards for appearance, casing, etc. I agree there seem to be an early "narrow" width and a later "wide" width between S-100 connectors. Is there a standard or commonly accepted practice for center to center "wide" board spacing or is it arbitrary? My intent is for a small (4 slot) motherboard used for hobbyist prototyping not a full blown system. The primary application would be the development of new peripherals using prototype boards. I expect that the use of wire-wrap sockets would be common requiring some clearance on the copper side and that the ICs and passives would be socketed. My estimates are that wire-wrap sockets need just bit over 1/2" clearance on the copper side and that most socketed ICs/passives require 1/2" clearance on the component side. Allison's estimate of 1" centers for the boards seems like a reasonable compromise. It won't get every possible combination but enough to be useful. The purpose is to allow low cost prototyping not for a full blown long term system installation. Cost is of primary importance which translates to little PCB surface area as possible while still being useful. BTW, Digikey carries a couple of types of S-100 compatible connectors but they are not cheap. Sullins and EDAC 0.125" spaced, 50 position, 2 row, 100 pin, PCB through hole solder tails card edge connectors run from about $8 to $12 a piece. I can get them surplus occasionally. eBay sells them too but are the wire-wrap variety which would work but is a gross abuse of a wire-wrap connector to solder it into a PCB. It can be done but I wouldn't tell anyone about it. :-) Thanks and have a nice day! Andrew Lynch