Hi Alain!

I've got one more new picture up of some bigger nodules I found. Go to the
same URL: http://www.driveway.com/share?sid=e25a88c4.8e904&name=Pictures

Look at Barrelnodules.jpg...this picture is a worst case picture. But you are
right about seeing the glass weave pattern in the hole walls in a lot of the
barrels.

The different metal color is not the illumination...it definitely is lighter
in color...almost silver in color. In the picture I've arrowed to where some
of the same plating that is on the board surface has coated a portion of some
of the nodules near the top of the hole...the rest of the barrel is light
colored and dull looking...

I don't have a cross-section, but I think I will definitely get one done.
Going to call the fab vendor too...I was just trying to understand what this
is before I call. Don't want to put my foot in my mouth.

Still scratching my head though...

-Steve Gregory-

> Hey Steve,
>
>  Small nodules inside plated hole walls are not unusual, however in the case
>  of your boards it seems to be the termination of the glass-weave that is
>  found in the prepreg and laminate. This may suggest thin plating thickness.
>  What is the finish on these boards? This kind of finish is not usually
>  expected after HASL, but may be more visible with other finishes.
>  For the dirrerence in colour, is it possible that the difference comes from
>  the variation of the illumination angle?
>  Did you do a cross-section, microsection, of the board?
>
>  Just trying to help,
>
>  Alain Savard, B.Sc.
>  CAE Electronics Ltd.

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