Hi SJ!

I've heard of this problem more than just a few times. Former TechNetter Earl
Moon ran across this problem and solved it easily.

You can go to: http://www.stevezeva.homestead.com and look at "Creative
Engineering" at the top left-hand picture there. What? You don't want to fix the
problem like Earl did? Why not?

Just kidding...Earl did what he had to do so the board would play. I believe
in his case it was more part related than any manufacturing issue.

I've had an intermittent connection with a BGA once. It was a VERY expensive
560-ball Xilinx device, that I really didn't want to have to remove and
replace because of it's price. The part had eutectic balls.

Test said the part would play when pressed on. So I figured I had nothing to
lose by fluxing the part liberally beneath it, and then taking it over to my
rework station to reflow the BGA and hope that maybe the intermittent
connection would heal itself.
The soldering gods were with me that day and it worked. The board passed the
initial test after rework, as well as subsequent tests after thermal cycling.

Some days you're just lucky I guess...

-Steve Gregory-


> Dear Technetters,
>
> We encountered BGA chip having intermitten contact issue in our prototypes.
> When we pressed hard on the BGA chip, the prototype worked ok. We need advice
>
> on how to tackle this issue from prototype building's point of view. What
> measures should be taken to make sure "no contact issue" during prototype
> building.
>
> Your advice is very much appreciated. Thanks in advance.
>
> Best regards,
> SJ Liew
>


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