posting code snippets

Gene Heskett gheskett at wdtv.com
Sun Mar 2 13:20:49 CET 2014


On Sunday 02 March 2014 07:05:06 Alister did opine:

> On Sun, 02 Mar 2014 09:16:35 +1100, Chris Angelico wrote:
> > On Sat, Mar 1, 2014 at 1:31 AM, Grant Edwards
> > <invalid at invalid.invalid>
> > 
> > wrote:
> >> You drag out the lab scope, logic analyzer, spectrum analyzer, sweep
> >> generator, strip plotter, and the machine that goes "ping".  You
> >> start to get everything set up to nail that problem securely to the
> >> dissecting board.  Long before you actually get to that point, the
> >> problem becomes intimidated and reveals itself and a solution.
> > 
> > *ALL* my machines go ping. It's fundamental to network debugging. I
> > know that's not what you meant, but somehow it comes to the same
> > thing. :)
> > 
> > And yep. That is so absolutely right. Problems know when concealment
> > becomes pointless.
> > 
> > ChrisA
> 
> As a maintenance engineer I find there is also an opposite factor in
> operation.
> Equipment manufacturers appear to include an "Engineer Proximity
> Detector" in all designs that cause the equipment to work flawlessly
> when triggered.
> 
> The issue the customer has been complaining about incessantly never
> occurs whilst there is an engineer on site.

Most sensitive when any cover has been opened.  It took me 5 years to find 
an intermittent video insert problem in a piece of Chyron gear, and when I 
found it, I called the guy at Chyron whose name was on the schematic page 
and told him in no uncertain terms that the best part of him ran down his 
mothers leg.  He'd used a spare gate in a quad nand gate package as an 
inverter, a common practice when you need just one more inverter in a 
design.  Nothing at all wrong with the concept, but the idiot left one of 
the two inputs floating, disconnected.  That is an absolute no-no in any 
digital logic circuit, and will bite somebody on the ass, repeatedly. And 
since I could only get at it for not more than 20 minutes at a time because 
of its duties, I am ashamed that it took me 5 years to find it when the fix 
was half an inch of wire wrapping wire to tie it to the other input pin.

There is not a digital logic chip book on the planet that doesn't contain 
warnings about floating inputs.

Yeah, I CAN be one of those to idiots.  As Marion Morrison, aka John Wayne 
was fond of saying in his movies, stupidity should hurt.  And this guy 
deserved to hurt.

Cheers, Gene
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

NOTICE: Will pay 100 USD for an HP-4815A defective but
complete probe assembly.




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