>
>Setup: pic chip controlling a motor in a typical h bridge. PIC just
>happened to be an EPROM variety compleat with window.
>
>System was on and running, customer said "Looks cool, gotta get a photo for
>the folks back home". He grabbed his camera, click, flash, bang, smoke jets
>out, motor stops, shows over.
>
>Seems the flash latched up the photo sensitive pic and caused just the
>right outputs to go on to fire top and bottom of the h bridge simultaneously.


ROTFLMAO!!!  They DO recommend that you cover those windoes!

I've never had THAT experience, but I did have an ericsson 3717 crater,
while I was sitting talking to the rep about excessive cratering. It was
just sitting idle, power on.  Turns out there is a max switching frequency
on the choppers, which is poorly documented, and apparently none of their
tech guys were aware of, that we were exceeding. So, in some parts, one
part of the bridge was not quite off when the other part was turning on.

Good timing though, we had been talking for maybe 15 minutes about this
very problem, and suddenly smoke is pouring out of the product, little
flame jets inside, but the case masked that from view.

--
Dave's Engineering Page: http://www.dvanhorn.org

I would have a link to http://www.findu.com/cgi-bin/find.cgi?KC6ETE-9 here
in my signature line, but due to the inability of sysadmins at TELOCITY to
differentiate a signature line from the text of an email, I am forbidden to
have it.

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