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Document Title: [Space Invaders ROM Hack.html (html file)]
> > On Tue, 29 Jun 199908:54:22 -0700, Matt Rossiter <matt@rossiters.com>
> > wrote:
> >
> > >When you re-strap the board, on boards such as Space Invaders, to use
> > >2716 Eproms instead of the 9316.� Do you have to use the TMS2716
> > >Eproms or the normal 2716s?
>
> Another fun way is to burn all 4 or 5 images into a 27128 or larger
> and simply add 4 leads or so to the address jumpers.� No cuts needed.
> I can post details later if anyone is interested.
Due to the underwhelming response, I'm going to post the details anyway.
I started with a Bally Space Invaders board.
S6 ROM jumpers were set to AD11->a, AD12->b, AD14->c
I then took a 27256 and burned in both the Space Invaders set and
Space Invaders Deluxe.� I can do this because I own both boards so
don't anyone try to get smart.
The ROM set has to be merged and burned in with the H ROM lowest and
the higher segments filled with whatever to make up 2 full 16K
blocks.
This new ROM can be plugged in to any of the ROM sockets but sockets
F and G are closest to the jumpers that we need to connect to.
Plug it in with bottom pins lined up. The top 4 pins hang out.
Now for the jumpers.� They're really quite simple.
I used a 28 pin socket, bent out the following pins and
soldered wire wrap wire to the legs.� The socket itself can then
be plugged in to the existing ROM sockets.
Pin 1 to GND
Pin 2 to AD12->b jumper.
Pin 20 to GND
Pin 22 to GND
Pin 23 to AD11->a jumper
Pin 24 to AD14->c jumper
Pin 27 to the center pole of a switch between GND and +5 to switch
games.
Pin 28 to +5
BTW, I've heard that you can run regular SI on a Deluxe board
but not Deluxe on a regular. Something to do with some hardwired
code on the sound board. I used a Deluxe board so the dual game
worked for me. You can make a single game version by just using
a 27128 and ignoring pin 27. Ground it, tie it high, I don't
remember what it does. You can even fit regular SI into a 2764.
You'll still need those jumpers at pins 2, 23 and 24. Only two of
them on a 2764.
