I was thinking the same thing. It would seem to work much better than an analog protection
scheme. Especially when games like star wars depend on moving the beam out past the edge
of the screen momentarily. Plus, the protection algorithm could be tweaked, improved, or
whatever just by reburning the code in the microcontroller.
Clay Cowgill wrote:
>
> Couple thoughts...
>
> I was playing with TVS (Transient Voltage Suppressors) parts a while back as
> a form of input protection on older WG6100 (and similar) monitors. They
> might be a worthy option for your input clamping. Super-fast turn-on, high
> current, bidirectional... It looks to me like they could easily thwart the
> dreaded "dead at max deflection" problem.
>
> One other idea from a few years back-- why not add a "smart" spot
> killer/supervisor? Just a little microcontroller and a couple fast
> comparitors or a little A/D or something. Have it's sole job in life be to
> sit there and watch the X and Y inputs. If it ever doesn't see axis
> crossings for more than a couple hundred milliseconds, turn off the color
> guns (spot killer). If it ever doesn't see axis crossings for more than 4
> seconds, turn off the deflection amps (transistor-saver). If it ever
> doesn't see axis crossings for more than 15 seconds, sound a piezo-beeper
> alarm. As a little extra bonus it could have four LEDs that show the
> quadrants of the monitor-- light the appropriate ones in the event of
> failure to help debugging...
>
> -Clay
Received on Wed Nov 3 11:57:58 1999
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