Re: Star Wars stray line on death star explosion

On Thu, 10 Dec 1998 10:44:47 -0600 (CST), Mark Jenison <jenison@cig.mot.com>
wrote:

>Could
>someone explain to me technically why the monitor "blooms" during the Death
>Star explosion?

That one I can explain.

The low voltage regulators used to supply voltage to the HV section (the 7824
and 7924's in the Amplifone) can not handle the current needed to run the HV
section, when that many vectors are drawn. That many electrons hitting the
screen requires more High Voltage current which in turns requires MUCH more low
voltage current (Amps * Volts = Watts, less Volts, more Amps, etc.)

Since the regulators shut down at around 1.5 amps, and the explosion apparently
requires more than this, there's a problem. Since not enough current is being
supplied, the proper HV cannot be maintained, and as you know from other
problems you might have encountered in the HV section of a monitor, as the
voltage drops the picture blooms.

The Atari "Fix" for this was to place a couple of resisters across the
regulators. (50 ohm? I forget the value..) When the regulators go into
current shut down at around 1.5 amps, these resistor act to bypass the regulator
and thereby supply more current to the HV section at the time of the explosion.

This can help, but all regulation is lost so the picture is still going to bloom
and shrink in direct relation to the number of vectors drawn.

A design like the LV2000 where the current capabilities of the regulators are
amplified using a couple of high current pass transistors, should compensate for
this. Though I remember someone trying this and it didn't work too well. It
could be that even given an infinite amount of current at it's input, the HV
section itself may not be able to supply the current needed for a Death Star
explosion, without itself being beefed up a bit.

May guess is Atari engineers said "Check it out, when the explosion happens the
monitor is all over the place! Cool! An added 'Feature!'"

After all, nobody expects everything to operate perfectly smooth during the
destruction of an entire Death Star! Talk about an electro-magnetic pulse!

-Zonn

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Received on Thu Dec 10 13:55:48 1998