On Thu, 31 Aug 2006 12:43:45 +1200, Barry Lennox
Gave us:

On Wed, 30 Aug 2006 22:58:42 GMT, "Arfa Daily"
wrote:


"Barry Lennox" wrote in message
. ..
On 30 Aug 2006 13:40:28 -0700, wrote:

Hi,

Quick newbie soldering question. I need to solder some wires to pins
on an SOIC package. I've never soldered something with this small of
pin spacing. Is there a trick for first tacking down the wire to the
pin before you solder so that it stays in place? Thanks for any tips

Kev

I used to do it all the time when SMD parts first came out. Invert
the chip and anchor it to a piece of blank PCB with a dob of hot-melt
glue. Then tin the wire and the SMD leg, touch the two together, then
reflow it with just a touch of the iron. Takes longer to write than
do!

Barry Lennox

One slight thing to remember though. When the chip has been placed on the
board upside down, in BluTack or whatever, the pin numbering is back to
front. Oh how many times have I caught myself out on that one ... !!

Arfa

Yep, that got me once or twice. But then the first thing I did was to
use a short heavy wire to connect the ground (pin 7 or whatever) to
the PCB. That served as a reminder of what was where. It also helped
hold the chip in place, as the hot-melt can loosen as soldering
proceeds.

If you are adding that much heat to a chip while soldering on simple
hook up wires, your are already outside the box from a proto builder
POV. Very bad technique to say the least.