Date   : Sat, 01 Apr 2006 13:08:18 +0100
From   : Fragula <fragula@...>
Subject: Re: Now Roms including Was Exile now off topic

Mike wrote:

> A useful trick is to use a 28 pin turned pin socket as a carrier. 
Indeedy. Well any socket at a push, but a nice turned pin one is far
more reliable and a better fit.

> The whole assembly can then be plugged back in.  If you've broken the legs
> off at the package edge, you're out of luck!
Well not completely. With a plastic package (admittedly not common on
EPROMs) its possible, with extreme care, to file/grind back the plastic
around the embedded stump of pin, then put the chip into the socket,
insert a stiffish bit of wire so that it presses securely against the,
only very slight exposed, stump, then feed a little flux and solder on
to ensure good contact. I've done it a couple of times, on 62256s (when
you only got two and a handfull of change from £100, and £100 was worth
a lot more) which, due to my penchant for flying address and write wires
all over the place, have probably suffered more than any other chip at
my hands, and on a Super-287 FPU, back when one of those was a holy
grail of performance) and its a fair bit of hassle, but better than
throwing away a more valued chip.


> I've often used this trick to get copies of damaged EPROMs, then burn new
> ones as working replacements.
Several of my, more frequently moved, ROMs have flat-pin IC sockets as
permanent fitments. it just makes them easier to plug in, and doesn't
seem to have any performance hit. Flat pin because I've replaced a lot
of the sockets on my board with turned pin jobbies, and don't want to
wear the inserts out plugging turned pin into turned pin, which wears
fast with removal/insertions, and the chips tend to end up having a bad
contact at that point. Flat pin into flat pin doesn't wear so fast, as
the sockets are springy. The electrical connection is fine, but
mechanically is not so good.


Cheers!

M.