Everett M. Greene wrote:
: Now, if there are any EEs present, perhaps they can explain
: why aircraft radios tend to fail in this manner whereas
: nothing much of anything else in the electronic world fails
: in a manner to produce heat and smoke. Are avionics units
: designed so close to the components' limits to cause this
: failure mode? I can understand a transmitter going up in
: smoke (while transmitting), but a receiver?

I'll take a stab at it... Probably a big reason why avionics fail like
that because they're older than most electronics. They're used for a longer period of
time so they can suffer individual component failures. "Normal" electronics tend to
get toss earlier, so their failures are more likely due to construction flaws.

They're also packaged very tightly, and cannot afford much overdesign that
would cause additional weight. Also, the environment they operate in is extremely
harsh... *huge* temperature/humidity swings, ridiculous vibration exposure, etc.

That's why I was singularly unimpressed with the internal build quality of the
Michel slide-in replacement radios. They're built with standard DIPs, through-hole
components, ribbon cables, and general run-of-the-mill consumer components. Minimal
strain relief and anti-chafing assembly. Makes for a less expensive unit, but I'm
sure they're more likely to wear/chafe than a well-built unit.

-Cory

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* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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