On Sat, 17 Apr 2010 08:52:13 +0100, "N_Cook"
wrote:

Removed in good order for re-use that is .

Hot air soldering station. About $150 to $200.

No specialised tools available
and I'm not going out to buy any for a once in a year job.

Don't worry. You'll need it more than once. The [deleted expletive]
BGA soldering is constantly failing in laptops, game machines, and
video cards. I keep reading about rumors of yet another class action
lawsuit over the HP DVxxxx series laptops, but haven't found anything.

I have a few
ideas but have never had to do it in earnest before. There is about 0.05 mm
clearance space between the balls under the chip and about 5 x 5mm in size.
A few minor SM can be removed from the opposite face of the board,
multilayer and about 1mm thick

Well, if you want to go cheap, get an IR thermometer to monitor the
temperature, and heat the BGA top with a small propane torch, or tin
can full of flaming alcohol and cotton. There are videos on YouTube
that show how it's done with laptops and game consoles. My batting
average for that method is about 50% success but getting better.
Search for "BGA rework" or "BGA repair".

There's nothing to do on the other side of the board and no need to
remove any SMD chips. Everything is done on the BGA side.

Getting the chip out is easy enough. With enough heat, the BGA chip
will just lift off the board. Getting re-attached is a major project.
Search YouTube for "BGA reballing". I've tried replacements, using
brand new chips, with non-trashed solder balls, but using hand tools,
with zero success. It really does take all the hardware in the videos
to do it right.

Good luck.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558