Re: Asteroids Deluxe Repair Story Part 2

Yes, blacklight will make the phosphors glow. They would REALLY be glowing if
it weren't for the thick glass of the CRT (glass attenuates ultraviolet light,
if you need to pass ultraviolet light with little attenuation you use quartz
instead of glass). Usually the black light doesn't shine on the tube directly,
it's usually on the other side of a mirror (which absorbs even more of the
ultraviolet, especially if it's smoked glass like many of the Atari games use).

If you need to lessen the effect more you might try a sheet of
ultraviolet-blocking plastic (such as is applied to house windows to keep out
the ultraviolet part of sunshine) over the mirror or CRT surface.

Jon Raiford wrote:

> Well, after learning my lesson with cleaning the edge connector and
> socketed chips' pins, I still had a problem to overcome. The game still
> played blind. I knew that it needed new DAC's, so I installed a couple
> AD561's (it originally used MC6012's). It was late and I didn't have any
> sockets, so I just soldered them in. As you'll soon see, this was a big
> mistake DOH!
>
> Before explaining my second major mistake, I should say that I was able to
> actually use my scope, logic probe, and DMM to find a bad TL082. Woohoo!
> I guess I really am getting better at this stuff. Admittedly, I did call
> my brother for some help, but I found the dead op amp while waiting for him
> to call me back :)
>
> As it turns out, that fixed it right up :) Well, it showed a picture at
> least.. Apparently, Asteroids Deluxe doesn't really like those 561's. The
> picture was shifted down and to the right quite a bit. Luckily I had my
> brother on the phone at this time and he helped me figure out (well, he
> told me.. I didn't help much) that the DAC had the ability to adjust the
> zero'ing point by putting a 50k pot between pins 2 and 15. Here's where my
> non-socketing mistake kills me.. The game board has a trace between those
> pins right underneath the chip. I had to pull the chips, cut the trace,
> install sockets, solder the new pots to the DAC's, and install them. Live
> and learn, I suppose.
>
> Now the game plays great, but I have a couple questions.. First, is the
> hack for installing centering pots documented anywhere on the net? This
> would have helped me a lot. And second, is there a reason why the black
> light makes the monitor glow a little bit? It looks like the black level
> needs to be adjusted, but its only the black light doing it (or maybe its
> the marquee light shining through). Its so close to being perfect in
> there.. I'd love to fix this.
>
> Jon
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--
Windows:
32 bit graphical interface for a
16 bit patch for an
8 bit operating system written for a
4 bit processor by a
2 bit company that can't stand
1 bit of competition.
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