IBM AT Drive Types
jwstephens at msm.umr.edu
Tue Jul 12 16:20:57 CDT 2005
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
It could have had to do with UL approvals as well, though I have no
basis to prove that.
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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