Hi All,

I'm looking for any comments or recommendations on reworking a board that
needs to have 2 35mm-313 ball BGAs replaced. The board has the following
details:

- 12" x 4", .062" thick
- FR4, Tg = 170 deg. C
- 10 layer, 4 planes
- ICs on top side, passives on bottom

The 2 BGAs that need replacement are adjacent to each other and span the 4"
width of the board and are about 2" off from the center of the board. And
there are 2 other BGAs on the other half of the board that I need to be sure
that I don't disturb in any way, a thermally enhanced 45mm-600 ball and a
27mm-272 ball.

My main concern is the potential warpage to the board in taking off each of
the BGAs with an SMT rework station. I have a benchtop batch oven that I'm
thinking of using to remove and replace them with because I feel it would
probably be better to heat the entire board rather than 2 sections of the
board individually with a rework station.

I would appreciate any experience anyone has had in dealing with a situation
like this and also any Do's and Don'ts that I should be aware of.

Regards,

Bob Walker
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