Re: Battlezone rom hack?

Here you go David.

Battlezone Single ROM Hack
Thu, 03/22/2012 - 22:12 — mspaeth

This modification allows you to replace all of the program ROMs on a
Battlezone board with a single 27128 EPROM.

*WARNING:*
Use this information at your own risk. Pull out the schematics and verify
what I say before making any modifications. It's not my fault if you blow
something up!

Battlezone is known for ROM socket failures. To ameliorate this problem,I
hacked my board to use a single 27128 instead of the 6 2716's.

First, a little background... the Battlezone memory map is as follows:
ROM0 4000-47FF 036414.01 (Shadowed)
ROM1 4800-4FFF 036413.01 (Shadowed)
ROM0 5000-57FF 036414.01
ROM1 5800-5FFF 036413.01
ROM2 6000-67FF 036412.01
ROM3 6800-6FFF 036411.01
ROM4 7000-77FF 036410.01
ROM5 7800-7FFF 036409.01

With the ROMs assembled as shown, address bit 14 can be inverted to gives
us a single chip enable for all the ROMs. To complete the hack we just need
to get ~A14 and run it and the additional address lines to one of the
existing ROM locations.

   1. Concatenate the 8 rom files (with ROM0 and ROM1 duplicated as shown)
   and burn into a 27128
   2. Pull all row 1 roms and replace the 24 pin socket at N1
   3. Bend up pins 1,2,20,22,27,28 on a 28 pin socket and place it at N1
   4. Wire M2:3 to K2:11 (A14)
   5. Wire K2:10 to N1:22 (~A14) [Pins are numbered for the 28 pin socket)
   6. Wire N1:20 to the ground trace (~CE)
   7. Wire N1:1,27,28 to the +5V trace (VCC, ~PGM, VPP)
   8. Wire M2:14 to N1:23 (A11)
   9. Wire M2:13 to N1:2 (A12)
   10. Wire M2:2 to N1:26 (A13)
   11. Drop the 27128 in at N1, and play more reliably!

(Original content published September 3, 2000)

On Thu, Aug 2, 2012 at 1:11 AM, David Shoemaker <davids@oz.net> wrote:

> Battlezone has a history of being unstable over the long run. Much of it
> related to the roms/sockets. Is there any documented hack out there to
> reduce the bank of roms down to a single rom?****
>
> ** **
>
> Or is the Braze high score kit about the best solution for this problem?**
> **
>
> ** **
>
> Thanks,****
>
> David****
>

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Received on Thu Aug 2 09:20:53 2012