Re: Tech: Asteroids Deluxe

Hi Drew!

I think you have too much ripple on the power supply for the monitor's
deflection circuit. Check the small filter caps (they are something like
100/50v) on the monitor board.

John :-#)#

Andrew Wilson wrote:
>
> >Whats happening is that the Y deflection is taking too long to get to it's
> >starting point, but only when drawing text.
>
> Forgive me for stating the obvious, but it sounds like the vector timing
> circuitry on the PCB is off. The voltage is being set to the correct levels, since
> the picture is showing up on the scope OK, but the voltage obviously isn't being held
> there long enough for the monitor beam to deflect to the correct position (the scope
> can deflect faster than the monitor, I guess). Are you sure it only happens with
> text - have you played the game to the point where you have a similarly large number
> of vectors on the screen? I have no clue how to fix it, but at least it's somewhere
> to look on the PCB.
>
> While we are on the subject of Asteroids Deluxe, I'm having a little problem
> with mine. The vectors all waver a little bit - they are straight, but they move back
> and forth just a little bit. It's not very noticeable when playing the game, but you
> can really see it in test mode (it looks like the lines are pulsing in and out
> slightly). Is this normal, or should the vectors in test mode all be rock-solid?
>
> Drew

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