Dear bin laden of PICworld, ;o)

>Anyways, in this case it created a short between the 5V and GND tracks.=
 The
>regulator is heatsinked (well isolated though) and got hot quite fast :-)=
 It
>only took a second before I had disconnected it again, but at that point=
 the
>PIC was burning hot at both VDD-VSS pin locations, and consequently the
>resistance when measured between VDD and VSS pins is ZERO. I might as well
>use a paper clip in the circuit rather than the PIC after this "incident"=
 :(

        Wow! You got a real cheap way to pic something, eh! ;o)

>But I'm wondering what it is exactly that kills the PIC in this case.
>Shouldn't the current simply go through the short (which is at the=
 beginning
>of the circuit, way before the power lines reach the other components)?=
 Why
>did the LED's and MAX232 survive fine but the PIC died?

        Very interesting question. I think what fried your PIC was not the short,=
 but the fast rise and fall of the +vcc rail, in a short circuit. 7805 has=
 a small period of no-regulation, that's small enough to rise vcc to 7, 8=
 volts and not fry the circuit. Since your veroboard is getting particles=
 "from the air", it creates an intermitent short, that makes the regulator=
 turn on and off very fast. Strange but true

        Solutions:
        1 - change your supplier of veroboard. Humidty in the board can cause it.=
 Is it fiberglass or fenolite?
        2 - build a better Power Supply.
        3 - What you have in your PS along the 7805? Can we see schematics of what=
 you did?
        4 - Call that small woman from "poltergeist" to "decontaminate" your=
 protoboard and say "this protoboard...is clean!"
        5 - pray

        Anyway, keep trying, everyone has fried a pic before during learning ;o)


---8<---Corte aqui---8<----

Alexandre Souza
taito@terra.com.br
http://planeta.terra.com.br/lazer/pinball/

---8<---Corte aqui---8<----

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