RE: BattleZone probs....

"are machined pin sockets more reliable than a good brand (say AMP) of
tin double-wipe sockets?
"

In a word, yes. There is a big difference. Here are some of the reasons to use
machine pin (MP) sockets:

1) Multiple contact points on the pin. The helix in the socket contacts the pin
    in many places and actually "digs" into the metal of the pin. Take a look at
    a DIP removed from an MP socket, you can see many shiny spots where the
    helix dug itself into the pin. This alone makes them much more reliable.
    Double wipes simply ride the pin and rely on a spring like property (which will
    eventually stretch).

2) The construction is such that it prevents the chips from working their way loose
    due to both thermal creep and vibration. Ask anyone who used to service Apple ]['s
    way back when. Many repairs simply consisted of pushing the chips back into the
    cheap sockets used in the computer's construction.

3) The number of insertion/removal cycles they can withstand and still be reliable is
    much higher. This of course mainly applies to development applications. The Cine
    multigame board comes to mind which has had well over 100 insertion/removals
    and is still going strong. BTW, I expect to have boards back after my upcoming
    vacation!

4) The connection is gas tight, preventing oxidation caused by both O2 and moisture.
    I've seen double wipes corrode themselves literally out from under the device.

5) They don't lend themselves to building up solder under the socket, again helping
    save your time.

6) Even at double the price, in hobbyist quantities, it's well worth the money (IMHO).
    (If you have to, skip lunch one day and your cost is covered)

As far as dissimilar metals are concerned, A) gold doesn't tend to react. All of the
gold pins/fingers I've come across look as good today as they did 20 years ago.
B) Most of the devices which built up "black crud" on the pins were the ones where
there is some silver content in the metal, such as on mask roms. Look for the gold,
gold is good.

It's no coincidence the AMP double wipes cost less than the AMP MPs.
It really boils down to whether you want to spend your money on buying
good sockets or your time on finding bad ones. Experience has taught
me that IC sockets are a common point of failure. Therefore, in an effort
to minimize or eliminate it I use the good sockets. I would sooner just
solder the chip to the board than use a cheap socket which I know is
going to fail.

Hope this helps someone save some of their time or sanity!

-Mark

Received on Wed Jan 20 20:54:01 1999