SBC6120 (a build-it-yourself PDP-8 clone) Last Buy and EndofLife

[Allison]

>
>Subject: Re: SBC6120 (a build-it-yourself PDP-8 clone) Last Buy and EndofLife
>   From: William Donzelli <aw288 at osfn.org>
>   Date: Mon, 05 Jun 2006 14:49:06 -0400 (EDT)
>     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>> Oh, and anything you want to be reliable......
>
>Also, when sockets are used in large quantities, manufacturing yield takes
>a dump. We have all mashed a pin or two in our lifetimes, trying to get
>something inserted (anyone that hasn't is a liar!). Now multiply that by
>several orders of magnitude on the assembly floor.
>
>ENgineers should try there best to avoid sockets. Period.
>
>William Donzelli
>aw288 at osfn.org

I use them where there are programable parts that can't be blasted in
circuit.  Sometimes when the part used is a temporary sub (74ls for a 74HCT).
My preference is machined pin or the better sidewipe when I have to.

However my worst experiences are socketed board for failures that 
were the socket itself.  TI and RN made a edgewipe that was the absolute
pits for relibility. By edgewipe I mean the narrow edge of the pin
not the wider face.  I've desocketed 4 NS* MDS controllers that used them
both kit and factory and all had no bad parts but plenty of inop sockets.


Allison