IBM AT Drive Types

[Chris M]

older monitors were not meant to be left on w/o a
video signal driving it is my understanding. I used to
have an Ikegami 19" fixed frequency workstation
monitor that went kaput possibly due to this reason.
But it was of a later vintage...might have just been
due to crap out.

--- jim stephens <jwstephens at msm.umr.edu> wrote:

> originally the IBM division that did terminals owned
> the PC and that
> may have had something to do with it.  It was later
> during a squabble
> over it's impact on system sales that it finally
> broke loosed into a separate
> division.
> 
> It could have had to do with UL approvals as well,
> though I have no
> basis to prove that.
> 
> Jim
> 
> Tony Duell wrote:
> 
> > > Its my understanding (but I've only seen it as a
> rumor, not as hard
> > > technical fact) that the reason the original IBM
> Monitors plug into the
> > > PC Power Supply and not directly into an outlet
> is that they were
> > > vulnerable to damage (probably the same
> horizontal drive problem) if
> > > left powered on independent of the PC.
> >
> > I've heard that rumour too, but I can't understand
> why, after looking at
> > the schematics. The horizontal drive is
> transformer-coupled, so it
> > doesn't matter if the input gets stuck high or
> low, it still won't turn
> > on the output transsitor.
> 
> 



		
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