[amsat-bb] Re: Surface Mount Repair

[i8cvs]

----- Original Message -----
From: "Roy" <rdwelch at swbell.net>
To: "AMSAT BBS" <amsat-bb at amsat.org>
Sent: Saturday, November 03, 2007 11:38 PM
Subject: [amsat-bb] Surface Mount Repair

> Hi Guys,
>
> I am trying to replace a 22 pin surface mount IC on a piece of Panasonic
> video quipment.  I have all of the leads unsoldered but now I find that
> the IC is stuck to the board, maybe intentionally.  It doesn't appear to
> be just the circuit board coating.  It's more like the whole bottom
> surface is cemented.
>
> I would appreciate hearing from anyone, off line, who has experience in
> removing a stuck IC from the board.  I have tried flux removerand 91%
> Isopropal Alcohol with no luck.  I hesitate to force it or destroy the
> chip since there are traces running beneath it.  Any ideas of a safe
> solvent or another way to unstick this thing?
>
> --
> Roy -- W0SL

Hi Roy, W0SL

If you are sure that the IC is gone and it must to be replaced then removing
the stuck IC from the board is not strictly necessary.

1) Solder again all the original leads to the board.
2) Using a small and suitable scissor cut all leads at the point from where
     they  just comes out from the IC
3) Open all leads a little bit apart
4) Superpose the new IC over the old one and solder all new leads to those
     original leads coming out from the board.

I did it several time when to remove a IC from the board is difficult and
complicated.

Best 73" de

i8CVS Domenico