Re: Tempest Eats EPROMs

Thanks for the input/lesson guys! Being the cheapskate that I am, I may
have to stick with solder tail though... (Unless I can score a bulk lot
of machine pins on ebay or elsewhere...)

Regards,
Noel

Gregg Woodcock wrote:
>
> ----- Original Message -----
> From: <solarfox@texas.net>
> To: <vectorlist@synthcom.com>
> Sent: Wednesday, October 11, 2000 9:59 PM
> Subject: Re: VECTOR: Tempest Eats EPROMs
>
> > On Wed, 11 Oct 2000 19:53:36 -0500, you wrote:
> >
> > >Sorry if this is a bit off topic, but does anyone else prefer machine
> > >pin type sockets? I believe Gregg Woodcock also recommended those. I
> >
> > I _vastly_ prefer them to the cheap single-wiper type, yes; I've found
> > them much more reliable in the long run.
>
> As do/have I.
>
> > >am having trouble with the theory here. It seems to me that if you use
> > >machine pin sockets (with the conical round holes and no spring
> > >tension), that if there are any differences in the pin lengths of your
> > >IC, that the shortest pin might not make good contact. Whereas, with the
> > >other style (solder tail?), the sockets have spring tension and apply
> > >pressure to the sides of the IC pins. Pin length would therefore be
> >
> > The pin lengths would have to be _very_ uneven for it to make any
> > difference, really... maybe a part that's been desoldered from a board,
> > with trimmed leads, might present a problem, but new parts or parts
> removed
> > from sockets will be fine.
>
> The pin tail begins to grip about half way down a standard length. I have
> many times
> had chips whose pins were trimmed which would not grip. It is easy to tell
> because
> you can feel them not grip on the way in and they may even jiggle! In any
> case, it
> has always been totally obvious to me when there has been a problem.
>
> > >less critical. Also, It would seem to me that machine pin sockets would
> > >wear quicker, in situations where an IC has to be removed and
> > >reinstalled several times. (the holes could become rounded out).
> >
> > Well, yes, _eventually_... but if you need to insert and remove a part
> > _that_ many times, you really should install a ZIF socket instead. :)
> I've
> > used machined-pin sockets on some prototypes, though, where I ended up
> > pulling an EPROM or microcontroller in and out a couple dozen times over
> > the course of development, and never had a problem with it...
>
> I have never heard, nor would I ever expect, that a machine pin socket's
> holes would
> wear. Have you looked at them? They are VERY thick! What will happen,
> however,
> is the legs of the IC will be crimped a tad more each time the chip goes
> in/out. Eventually
> (and I am talking after scores/hundreds of times) the legs may be so curved
> that they
> no longer make good contact. The solution? Flatten then back out with a
> pair of pliers.
>
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Received on Thu Oct 12 00:02:42 2000