> I have recently seen a Newt with one of the tracks near the ROM and memory
=
> chips "blown" as if exploded over a very small area. The owner said it =
> happened at switch on and under magnification it looked quite dramatic. I
=
> reckon it was caused by 'static' discharge.
I do not completely agree with that. The energy of a static discharge is not
very high. It is the high voltage only which causes damage, especially to
the very thin semiconductive layers in electronic components.
The described accident of a blown track on a PCB does require energy to heat
up and evaporate the material. Beside voltage there is current needed too
and all together over a longer time. I can imagine that in the presented
case the Newton NiMH accu delivered this energy. Accus normally have a very
small internal resistance and are thus able to drive a current of up to
several amperes, depending on the load resistance.
Electronic devices like the Newton are designed to withstand ESD. In order
to get an approval each type has to pass a ESD test and has to survive. The
developers integrate normally several protection circuits at cascaded
positions in the electronic circuit. Even on chip level is built-in
protection circuitry which can take over a smaller amount of ESD energy then
external elements.
> Your message suggests a correlation between the synthetic case and the =
> unexpected turning on. Would you deduce that from your recent experience?
=
> If so it seems 'static' discharge might somehow be involved.
I noticed too that the Newton switched on by a static discharge, e.g. close
to the NIC port. However, before this can be confirmed it is necessary to
exclude any influence of software. To exclude ESD one could place the Newton
in a ESD protection bag and put it then into the Caterpillar pocket. Maybe a
single layer of an ESD pouch sewed to the interior of the pocket would fix
the problem and dont disturb to much.
-- With best Regards / Viele Gruesse!Marco Mailand
http://slsbd.psi.ch/timing http://slsbd.psi.ch/~mmailand/ https://www.paypal.com/refer/pal=YYD3VUXUVD2YG
-- Read the List FAQ/Etiquette: http://www.newtontalk.net/faq.html Read the Newton FAQ: http://www.guns-media.com/mirrors/newton/faq/ This is the NewtonTalk mailing list - http://www.newtontalk.net
This archive was generated by hypermail 2.1.2 : Sun May 05 2002 - 14:03:03 EDT