Testing a 1488 line driver...

Roy J. Tellason rtellason at verizon.net
Thu Jan 3 10:53:21 CST 2008


On Thursday 03 January 2008 11:04, Mr Ian Primus wrote:
> > Something might be loading it down, too.  I'd check
> > for that before assuming it's bad.
>
> Yeah, like maybe a shorted 1488 :)

I don't recall too many of those with that failure mode...

> See what else uses -12v, and work from there. For what it's worth, I've
> replaced quite a few 1488/1489's - they typically get zapped in terminals
> when people do stupid things with the serial lines while the terminal
> is plugged in.

Like what sort of stuff?  The most I ever saw those fail was one company that 
had a wire running from one building to another and that used to pick up a 
lot of transients from lightning.  They'd bring those terminals in fairly 
regularly.

> I don't know if a failed one can short out the -12v rail though. Never seen
> it happen specifically, but that doesn't mean it can't.

I tend to not rule stuff out completely,  and avoid surprises.  :-)

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin




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