Xref: utzoo comp.sys.ibm.pc:15843 comp.arch:4958 comp.graphics:2538
Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!pasteur!ucbvax!decwrl!sun!pitstop!sundc!seismo!uunet!lll-winken!lll-crg.llnl.gov!brooks
From: brooks@lll-crg.llnl.gov (Eugene D. Brooks III)
Newsgroups: comp.sys.ibm.pc,comp.arch,comp.graphics
Subject: Re: How did this program burn out two monitors?
Message-ID: <7658@lll-winken.llnl.gov>
Date: 24 May 88 22:11:05 GMT
References: <10244@agate.BERKELEY.EDU> <17460@glacier.STANFORD.EDU>
Sender: usenet@lll-winken.llnl.gov
Reply-To: brooks@lll-crg.llnl.gov.UUCP (Eugene D. Brooks III)
Organization: Lawrence Livermore National Laboratory
Lines: 11

In article <17460@glacier.STANFORD.EDU> jbn@glacier.UUCP (John B. Nagle) writes:
>       This is an old known bug.  You can burn out the IBM monochrome
>monitor by stopping the horizontal sweep while keeping everything else
>running, and the Hercules card gives you enough control to do this
>under software control.  The video chip lets you select the horizontal
>and vertical sweep rates independently, and zero rates are possible.
>However, the horizontal sweep is used as the oscillator for a switching
>power supply, as is typical in TV circuits, and with the sweep rate at
>0, DC flows through a coil with high inductance but low resistance,
>producing an excessive current that burns out the coil.
This is GREAT, I have been looking for a really good idea in PC viruses,
and THIS IS IT!