On Oct 24, 4:57*am, Jeff Liebermann wrote:
On Sat, 24 Oct 2009 07:58:34 +0100, "N_Cook"

Ant chance of Beryllium oxide or whatever the serious nasty is , likely to
be inside?

Berylium oxide is white and is used as an insulator. *It looks like a
hard ceramic. *I looked at the data sheet but no insulator material
was specified.

Beryllium oxide is rare, would usually be tinted (I've seen pink and
maybe purple) as a warning.

As others have noted, the likelihood is that the die has melted or
heated enough to rediffuse into a blob without junction or layers.
A 20A rectifier would usually get lots of heating after an initial
fault, and the result is always a blob; nothing to learn there.