[sdiy] mis-soldered IC....

[harry]

Batz Goodfortune wrote:

<'liberally' snipped to pass Australian IT customs ;^)

> Y-ellow Harry, Tom 'n' all.
>
>
> >Also... if I EVER have to unsolder a chip... I use a socket the next
> >time... so
> >that
> >the board will never get unsoldered again at the same pads.
> >
> >And I use sockets in the first place....  (AMP Diplomate brand)
>
> Have shares in the company Harry? My dog ate my shares in Microsoft.

Hmm... would your dog like my M$oft shares as well ??? I don't have a dog...
or a bird... birdcage is a good place as well...

No I have no AMP shares... as AMP is a Tyco division its a damn good thing ;^)
Maybe Tyco should have stuck with making toy trains (or other products) instead
of
making money on money (or merger, or paper... well you could use the paper in
the
birdcage but we already discussed that...)

> Socketing ICs have a disadvantage that they can become dislodged in
> transit. It is also not uncommon for them to just stop working for no
> apparent reason. This is due to expansion and contraction allowing
> contaminants into the interface. Some people swear by machined pin sockets.
> Other's hate them. I'm undecided but a bit of gold plating (Or gold painted
> as we swore was the case with Duck Smut sockets.) never goes astray. A
> solution to the dislodgement problem is simply to use a bit of hot-melt
> glue or a dab or rubber cement between the chip and the socket. DO NOT use
> supa glue! Not if you ever want to repair it.

There are two schools... One is to use noble metals for the contacts. GOT to
use
selective plated gold or you are asking for trouble. Gold and solder do not
always
mix well... sometimes they look 'wetted' but are really subject to a crack
along the
intermetallic interface (phew!).  The noble metal school thinks that corrosion
will not
occur, and usually use machine screw contacts with low retention forces.

The other schools use tin-lead plating, and ultra high retention (contact)
force... going
for the gas-tight connection as is done in wire-wrap construction.  I prefer
this... and the sockets I mentioned have excellent performance in high
vibration and severe industrial environments. Your MiniMoog would not last a
week here....

> But socketing in general is a real good idea. If you ever have to repair a
> commercial board it's always a good idea also. Since the boards are often
> pretty bad and take about 1 repair job before the tracks come un-stuck.
>
> There's really no avoiding the expansion/contraction problem unless your
> gear lives in a perfectly stable environment. Like the place in France
> where they keep the official metre measurement or perhaps Lenin's tomb or
> something.

Any gear of your's (Batz) could NOT be considered to be in a stable environment

:^P

> A guy I knew use to bathe his Apple ][ MoBo in isopropyl once a year. This
> thing was a total dog for this kinda stuff. Many people replace their PCs
> because they can't figure out what the random fault is. Twice a year here I
> usually have to go round and reseat all the cards. It's just the way it is.

get some AMP Diplomate edge connectors ???    (joke - no such thing...)

BTW I'd love to be "totally Icebox" right now. Had to take the Air Conditioner
apart
last night (4-5am) to get the house temperature below high 80s (F).  Send us a
care
package from Australia... I sure you have some icebox there...

H^) harry