SB-230 (aka SB-614)

[Steve Harrison]

At 06:58 PM 12/02/98 -0800, Terry Perdue wrote:

A potentially major clarification:

>You probably know this, but it's not the heatsink that's toxic, it's the
>Beryllium Oxide insulator between the 8873 and the heatsink, and only if if
>somehow turns to dust. It's not a risk unless you purposely grind on it and
>make a point to breath the resulting dust. It's the same ceramic that's used
>to encase RF power transistors,

The beryllium oxide in power transistors (not just in RF types) is a small
wafer located between the transistor's metallic mounting flange and the
silicon wafer itself. The white ceramic cap is just that: ceramic, NOT
beryllium oxide.

As Terry said, beryllium oxide is perfectly safe to handle, and is only
toxic in its dust or powder form.

Some external-anode power tubes with ceramic insulators also use beryliium
oxide although I'm not certain just where (I think only the base that holds
the pins, NOT between the anode and screen or grid rings). Eimac has
included handling sheets with their tubes since at least 1982, one
instruction of which concerns the beryllium oxide insulators.

73, Steve Ko0U/1

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