RE: Ampliphone HV FAQ is done!!!

> Yet the insulator serves no purpose here. On the HV board I looked at
> (a beige board) the heat sink was rivetted and solder to gnd. Since
> the tab of a 7824 is connected directly to it's pin 2, and pin 2 is
> also solder to ground, there is nothing to insulate, they're already
> electrically connected! If you remove the 7824 from the heat sink and
> let if float, then connect an ohmmeter to the heat sink and the body
> of the 7824 you'll get zero ohms of resistance. This being the case,
> what does the insulator accomplish (besides cutting down on heat
> transfer)?
>
Sometimes hardware manufacturer's do stuff like this simply for
"consistency". If I have one part the blows up in a shower of sparks if its
uninsulated, and another more or less identical looking part that doesn't--
do I really want to trust the first-year technician-guy to remember which
one *has* to be insulated?

"Remember to replace the insulators on the little transistor thingys" is
easier for the unexperienced to remember than "remember to replace the
insulator on the 7924, but not on the 7824, they look the same so check the
numbers and look it up in the book if you forget which is which".

(Plus, If it's running so close to the thermal shutdown that the difference
in heat transfer an insulator would make causes it to fail it probably
deserves a fan or something in the first place... )

-Clay
Received on Mon Jun 7 13:59:42 1999