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
> 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. :-)
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