[sdiy] When NOT to use sockets for chips ?

[harrybissell]

There are two basic socket types...

1) The screw machine type, almost always GOLD plated. They rely
on 'noble metal' to keep the connection good. Retention force sucks.
Most solder coated pins will eventually fail in these, but gold pins
would last forever.

2) The leaf type. These either achieve enough contact force to make a
'gas tight' connection in which case they last forever... or they don't
and suck as bad or worse than #1 above.

AMP Diplomate sockets have very high retention force, and wiping
action. They were very good. The new, cheaper TYCO versions are
well... cheaper.  I'm still using them but I notice a BIG difference in
the retention force. Maybe I'll try the higher quality ones... but hey
if anything sucks worse than a BBD, its TYCO. In fact they suck more
than all the BBDs that were produced, ever !!!

H^) harry

Scott Gravenhorst wrote:

> Experiences differ.  I've had some problems with sockets that made me
> stop using them in finished equipment except for those conditions Jim
> listed.
>
> Our experiences don't cancel each other, neither is right or wrong.
>
> For what you are talking about, I have used solderless breadboards to
> do proof of concept.  And an SBB is just a big socket, so in that
> respect, I do value sockets for experimentation.  I have blown things
> up on SBB while figuring things out.  Once I have the final schematic
> nailed down, it moves to stripboard where I solder all ICs.
>
> As always, YMMV.
>
> "Tim Daugard" <daugard at sprintmail.com> wrote:
> >From: "Scott Gravenhorst" <music.maker at gte.net>
> >
> >> obeyed.  There is no need to socket them unless you plan to abuse
> >them.  The
> >> odd IC that might fail (_extremely_ rare except for specific
> >devices with
> >> known issues) can be replaced an resoldered.
> >>
> >> Note that commercial equipment applies these rules as well, and
> >for the same
> >> reasons that Jim lists.  CPUs, RAM, and programmable option ICs
> >are the only
> >> ones that are socketed.
> >
> >If was building commercial equipment, it would definetely be no
> >sockets. MIL SPEC is no sockets, confromal coated. But for my own
> >equipent it is always sockets. I have destroyed one IC four times in
> >a piece of test equipment I built. Soldering and unsoldering that
> >chip would seriously weaken the board after three repairs (high
> >humidity environment - every cycle adds more posibility of
> >contaniments into the solder and copper). I don't have any problems
> >with socketed chips, even in things built 15 years ago.
> >
> >Tim Daugard
> >AG4GZ 30.4078N 86.6227W Alt: 12 feet above MSL
> >http://home.sprintmail.com/~daugard/synth.htm
> >
>
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