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January 1999

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Subject:
From:
"Stephen R. Gregory" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Thu, 7 Jan 1999 16:41:11 EST
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Hey ya'll!!

     SUCCESS! I was able to get that monster off!...(Now I just gotta' be able
to get it back on right...hehehe) If you remember, the whole reason I had to
rework it was because somehow they got the hole positions wrong in the board
for the two alignment pins at the bottom of the socket, which caused the
socket to be soldered one row off on the board. I'm still trying to get to the
bottom of how that happened (I haven't forgotten your request Roger, still
workin' the issue...).

     But I called CTI this morning and talked to them about trying to rework
this thing. I was told that they have heard of people reworking this socket,
but it's pretty much been hit and miss, and trying this, or trying that. They
said the one company that they know of who have got it down is SCI. I guess
they build a lot of product that uses this socket and they've had their rework
equipment modified to do this socket...you know, special preheater, nozzle,
etc.

     But, getting back to how I did it, it was a "Steve's start-up company
mode special". Don't laugh too much, 'kay? Sometimes when you don't have all
the things you want, you gotta make do with what you have...and I think if you
use common sense, and take things slow, you can do just about anything anybody
else can....maybe not as fast, but you can do it.

     My rework system is one of them fancy Hakko 850's...you know, the full-
vision (your own two-eyeballs), hand held unit. The nozzle I used was a 36mm
square one that's normally used for QFP's...this one matched the basic shape
of the pins in the socket. I had to take the cam lever, and the "Z-lok" cover
off to expose more of the pin's surface to absorb the heat. I also used my
trusty Fluke multimeter (it has a temperature function which you can plug a
thermocouple into and see temps real-time) and threaded the tip of the
thermocouple into the socket where it could tell me how hot it was getting
down around the solder joints.

I was pretty liberal with the flux bottle, and really coated things to help me
with heat transfer. Turned the Hakko on and watched my Fluke. It took about
two and a half, to three minutes for me to indicate around 210-220 degrees
centigrade inside the socket, and then I tested the socket with my tweezers
gently at the corner to see if it would move, it moved easily, and I pulled it
up without a hitch! Didn't even lift a pad!! YEEE-HAW! Not bad 'fer a in-gun-
ear, huh? Usually, you don't want to let us get anything sharp or hot in our
hands...(GRIN). The board had a little mole-hill where the socket was until it
cooled back down and straightened out. The socket was actually in pretty good
shape too, the plastic didn't degrade a bit.

Now, I just gotta figure out how to get this puppy located back over the pads
accurately without those guidepins, I gotta clip them off...I'll let ya'll
know how that goes...

-Steve Gregory-

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