Re: Modern myths

From: Nicolas Welte (
Date: 1999-04-22 14:22:09

Marko Mäkelä wrote:
> On Wed, 21 Apr 1999, William Levak wrote:
> > As you change the values from their optimum level, the image begins to
> > waver and distort.  Getting farther away, you lose sync and the picture
> > breaks up.  Even further, and the driver circuitry (technically known as a
> > ramp generator) ceases to respond to the signals and the screen goes
> > blank.  NONE of this damages the display in any way.
> What about the urban legends that one could damage a PC display by feeding
> wrong line frequencies to it?  I've heard of one friend's friend whose
> monitor let the smoke out only after a few seconds of wrong signals.  Has
> anyone really seen a flyback transformer or some other component that has
> fried because of out-of-specs frequencies?  (Hmm, now when I think of it,
> many PAL TVs keep a little noise when fed with an NTSC signal.)

I once blew a fuse in my Hercules monitor while I had it attached to the
C128. It was not the main fuse, but some other one in the deflection
part or so. I can't really remember anymore what I did, but probably I
tried some of these high-resolution hacks for the VDC chip and as I know
today they all give a shit about proper video timings. Most authors of
such programs just try which values show a stable picture on their own
monitor and that's it. Many programs don't even sync properly on normal
(non-multisync) monitors. Some programs even come with a 'VDC-editor'
for messing with the timing, but they lack an explanation of the values. 

Well, I replaced the fuse (it was soldered in!) and the monitor is still
working today. Of course I don't use it much anymore, it's only used a
control monitor for the fileserver. 

This message was sent through the cbm-hackers mailing list.
To unsubscribe: echo unsubscribe | mail

Archive generated by hypermail 2.1.1.