Programming and ROM socket information for Firepower.

ROMs included in this package are named by type and not by location.
Use the table below to find where your ROMs should be installed.

filename.474 = 74S474 PROM, 512 bytes
filename.716 = 2716 EPROM, 2048 bytes
filename.532 = 2532 EPROM, 4096 bytes
filename.732 = 2732 EPROM, 4096 bytes

ROM name                              Location
-----------------------------------   --------
GAMEROM  - Game program ROM           IC14 --+
PROM1    - Game program PROM          IC21   |-- This is the original
PROM2    - Game program PROM          IC22   |-- configuration of chips
PROM3    - Game program PROM          IC26 --+

FPCOMBO  - Game program ROM           IC14 ----- Alternative (see below)


GREEN1   - Green Label Flipper ROM1   IC20
GREEN2   - Green Label Flipper ROM2   IC17

SOUND3   - Sound ROM Type #3          IC12 - Sound Board

V_IC5    - Speech ROM                 IC5 - Speech Board
V_IC6    - Speech ROM                 IC6 - Speech Board
V_IC7    - Speech ROM                 IC7 - Speech Board


Firepower was unique in that it made use of the both the "PROM"
sockets and the "Game ROM" socket for holding game software.
Using both sets of sockets allowed Firepower to have an extra
1.5K bytes of game program.

Note that the original configuration of chips requires that MPU board
jumper J4 be installed and J3 be removed.  There are orange labels in
the cabinet and on the board noting this fact, but we state it again
in case those labels have disappeared over the years.

Replacing the ROM and PROMs for Firepower is difficult because the
bipolar PROMs are hard to find, and a device programmer capable of
burning them is even harder to find.

If the original chips are missing or damaged, the better solution is
to use the "FPCOMBO" ROM data programmed into a 2732, and make the
board modifications outlined below.


   SYSTEM 6 MPU BOARD MODIFICATION FOR USING "FPCOMBO" GAME ROM
   ------------------------------------------------------------
*********************************************************************
*                                                                   *
*         !!!!!! THE USUAL BIG DISCLAIMER SECTION!!!!!!             *
*                                                                   *
*  If you don't know how to work on circuit boards, don't even      *
*  think of doing this modification.  If you've been meaning to     *
*  learn how to work on circuit boards, don't even think of doing   *
*  this modification as your first project.  Get someone else who   *
*  is already skilled at circuit board work to do it for you.  If   *
*  you are concerned about maintaining 100% originality in every    *
*  way on your machine, don't perform this modification.  While it  *
*  has been designed to be easy to "undo" should the need ever      *
*  arise, it will permanently alter your circuit board where one    *
*  trace is cut.  A circuit board modified in the described way     *
*  will no longer work in any other games unless the modifications  *
*  are undone.  This is meant to provide a way to keep a Firepower  *
*  running, where the MPU board is expected to stay in a Firepower  *
*  forever more.                                                    *
*                                                                   *
*  While every effort has been taken to ensure the accuracy and     *
*  and viability of the Firepower combo ROM and the circuit board   *
*  modifications described below, this solution is provided with    *
*  no warranty nor support from Williams Electronics Games, Inc.    *
*                                                                   *
*  Your use of this information is at your own risk, and is         *
*  provided solely as a courtesy to enable you to continue enjoying  *
*  your Firepower for years to come.                                *
*                                                                   *
*********************************************************************

1. Remove any Game ROMs (IC14, IC21, IC22, IC26) from their sockets.

2. Remove any jumpers at J3 or J4 (to the right of IC15, a 74LS139).

3. On the bottom of the board, at IC14 pin 21, cut a notch in the
   heavy circuit trace on both sides of the pin.  Removing some of
   the existing solder on the trace may help.  The idea is to get
   rid of the +5V connection to the pin, while still leaving an intact
   solder pad at the pin itself.

4. On the back of the board, run a small jumper wire from IC14 pin 21
   to IC30 pin 14.  IC30 is generally not installed; it is the 16-pin
   chip outline just to the right of IC14 and just above the interboard
   connector.  Solder the wire through the hole at pin 14 of the empty
   IC30 location, and to pin 21 of IC14, making sure not to short it to
   the other side of the trace you cut at IC14.  This brings A11 to IC14.

5. On the back of the board, install a 4.7K ohm, 1/4 Watt resistor
   between pins 20 and 24 of IC14.  With the resistor leads bent at
   90 degrees at a comfortable distance from the body of the resistor,
   they should line up at just the right spacing to solder one lead
   to each of those pins.  Again, make sure not to short the pin 20
   connection to the jumper wire at pin 21, or the cut trace edges
   around pin 21.  This provides a pullup for the active-low chip
   select.

6. Install two small-signal diodes (example part numbers are 1N914
   and 1N4148; the same sort of diode used in the switch matrix)
   at locations J3 and J4.  The cathode (banded) end should be towards
   the TOP of the board for both diodes.  This allows either of the
   two Game ROM address ranges to drive the active-low chip select
   at IC14.

7. Program a 2732 with the "FPCOMBO" ROM data and install at IC14.  If
   the game doesn't already have working Green-label ROMs at IC17
   and IC20 you should of course install those too.



In case you ever need to restore the board to standard System 6
condition, do the following:

1. Remove the 4.7K ohm resistor, the jumper wire, and the two diodes
   installed as described above.

2. Bridge a piece of wire with solder between pin 21 of IC14 and
   the heavy 5V trace that used to connect to it.

3. Perform whatever J3/J4 jumpering and chip installations are
   required for the game the board is being used for.
