Stephen,

    I had socket that I was not comfortable looking
through to see the BGA alignment and soldering etc. So
I flipped the board onto the opposite side and viewed
the balls that way. I needed to make sure I new what I
was looking at in terms of tricky features on the
component side so that we did not mistake any feature
for a defect. This is one way you can see you
placement quality without going nuts with adjusting
the volts & mag. etc.

Hope this helps.

Tony Di Mauro
Circuit Technlogy Center
Haverhill, MA

--- "Stephen R. Gregory" <[log in to unmask]> wrote:
> Hi ya'll!
>
> Well, we just fired up the line this morning on a
> job we've ran before, and
> it's got a BGA on it. This time though, we're using
> a new Texas Instruments
> DSP (PN# TMS320C620GJC200) because the one that was
> used last time is
> obsolete.
>
> Well, when the first board came off the machines, I
> went to verify placement
> with the Glenbrook x-ray we have, and I could barely
> see through the part! If
> I turn the gain up to maximum, I can barely make out
> the balls, but I can't
> see anything that tells me if I'm on the pads...
>
> Has anybody ever run into this before? What do you
> do in a situation like
> this? The placement looks good in relationship to
> the silkscreen outline of
> the part...but I know I shouldn't depend on the
> silkscreen. But what else can
> I do?
>
> Fun stuff...
>
> -Steve Gregory-
>
>
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