Re: On attempting to make the 3.5" floppy adaptor to work...

["Michael J. Mahon" <mjmahon@aol.com>]

Michael J. Mahon wrote:
> Tristan Mumford wrote:
>
> > Michael J. Mahon wrote:
> >
> >
> > > Tristan Mumford wrote:
> > >
> > > > Michael J. Mahon wrote:
> > > >
> > > >
> > > >
> > > > > Tristan Mumford wrote:
> > >
> > >
> > > <snip>
> > >
> > > > > > I also managed to turn an 18f452 into a nice heating element. When 
> > > > > > I did
> > > > > > the reshuffling I managed to short the -12v to one of its IO lines,
> > > > > > which would have resulted in a nice 17v potential difference 
> > > > > > inside the
> > > > > > chip. Or is it 16v. Doesn't matter anyway. Now I have something to 
> > > > > > throw
> > > > > > at the neighbours cats.
> > > > >
> > > > >
> > > > > Aaaack.  ;-(
> > > >
> > > >
> > > >
> > > > I believe I measured a whopping 12ohm resistance between Vdd and Vss.
> > > >
> > > > Paranoia now has me keeping my finger on top of the uC the whole time
> > > > it's on feeling for a temperature difference.
> > >
> > >
> > > Been there--even slightly burned my finger!  ;-)
> >
> >
> >
> > I've fried too many chips outside the kitchen for my liking. Speaking of
> > which I actually did the silly thing of trying my teeth on the uC 
> > after it
> > burnt out. I did this to confirm my suspicion that I had destroyed a
> > ceramic packaged one.
> >
> > Did you burn your finger on the ROM or something different?
>
>
> Yep, the ROM.  From its rate of heating, I'd say it was dissipating
> about two watts, or 400mA from the +5 line!  That would be about 12
> Ohms...hmmm...perhaps another universal physical constant!  ;-)

That seemed like too much of a coincidence, so I just went and
measured the resistance:  3.0 Ohms!

I guess my fingers are getting more tolerant of heat, since that
works out to about 8 watts!

-michael

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