Re: Recording digital data to analog tape... revisited

From: Dave VanHorn (dvanhorn_at_cedar.net)
Date: 10/03/04 

Date: Sun, 3 Oct 2004 10:10:30 -0500

>>In the end, it was a
>>reverse-polarized screw that everyone noticed, and everyone discarded as
>>a problem source.
>
> A WHAT?

You heard me..

The screw was holding a transistor and it's heat sink, to the PCB.
It was supposed to be installed pointing up, with the nut on top, so that
the extra length pointed up into the heat sink area.. They installed it
pointing down, because it was easier to handle. This made the screw contact
the can of an electrolytic.

Now, the can is insulated from the cap terminals, > 10Mohms

Why did this cause the reg to go up in flames? 

-- 
KC6ETE  Dave's Engineering Page, www.dvanhorn.org
Microcontroller Consultant, specializing in Atmel AVR

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