Re: gEDA-user: Success with gEDA tools...

[Steve Meier <smeier@xxxxxxxxxxxxxxxxxxx>]

Reversed polarized cap? Those ones are easy to find upon power up :)

I don't think it is sufficient to rely upon the silk screen to provide
assembly instructions.

For cases like this you really need to provide written assembly
instructions and make following them part of the purchase terms.

But my experience is that especially on larger orders a certain number
of the parts will be dropped and thus not loaded by the p&p tool. These
then get hand loaded and can be put in rotated 180 degrees very easily.

Another example of the fifty fifty rule. Given two choices I will pick
the wrong one 80 percent of the time. Given one choice the odds of being
correct only improve to about 70 percent.

It got to the point that we require each board come with a tag telling
us which parts were hand loaded so that we could visually inspect the
board before power up.

Steve Meier


On Fri, 2008-07-18 at 23:00 +0100, Peter Clifton wrote:
> On Fri, 2008-07-18 at 11:45 -0700, Dave N6NZ wrote:
> > Steven Michalske wrote:
> > 
> > >>  Worked almost right away.  Note red wire and missing pullup. Keeps me
> > >>  humble.
> > > 
> > > Green wires are less humbling, i suggest them.
> > 
> > I look at design efforts like golf.  Low scores are better, but nobody 
> > plays a round with 18 holes-in-one in a row.
> > 
> > My most humbling: back in the 1980's I wrote an ECO with about 15 lifted 
> > pins and 50 or so red wires, a chip glued onto the board "dead bug 
> > style", plus a piece of coax (!). (Didn't catch *that* case in 
> > simulation....)  This on a board with about 180 TTL packages.
> 
> I just got a board back which the assembler rather keenly produced from
> draft files I'd sent during initial discussions.
> 
> Clearly labelled next to one part with silk-screen on the board 
> "BUG: CAPACITOR SILK +/- SWAPPED" (discovered during in-house
> prototyping, but I'd not got around to fixing it when I sent the draft
> files).
> 
> They stuffed the capacitor according to the silk (wrong), and didn't
> notice / think to check with me what this strange silk-screen text was
> about!
> 



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