compucolor

[Liam Proven]

On 5/8/05, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
> > [...] if the wrong value is entered,
> > it causes something dire to happen in the TV section's logic (eg, if the
> > horizontal frequency is too low then the flyback transformer's impedence
> > drops and draws a lot of current and smokes).
> 
> This is not as rare as you might think. Several machines -- the IBM PC
> MDA card + 5151 monitor, for exampe -- suffer from this. There is no
> horizontal oscillator chip in the monitor circuit, the line output stage
> (horizontal output stage) is driven from the signal produced by a
> software-contorlled IC (in the case of the MDA card, it's a 6845).
> Mis-programming that does just what you said....

Aha! The famed HCF instruction? :¬)

-- 
Liam Proven
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