Firepower Programming and ROM socket information.

ROMs included in this package are named by type and by location.
Use the table below to find where your ROMs should be installed.
filename.716 = 2716 EPROM, 2048 bytes
filename.532 = 2532 EPROM, 4096 bytes
filename.732 = 2732 EPROM, 4096 bytes

ROM name                              Location
-----------------------------------   --------
Fp_IC14.732  - Game program ROM       IC14 

Grn_IC20.716 - Green Label Flipper    IC20
Grn_IC17.716 - Green Label Flipper    IC17

Snd3IC12.716 - Sound ROM Type #3      IC12 - Sound Board

V_IC5.532    - Speech ROM             IC5 - Speech Board
V_IC6.532    - Speech ROM             IC6 - Speech Board
V_IC7.532    - Speech ROM             IC7 - Speech Board


Firepower was unique in that it used both the three "PROM" 
sockets at IC21, IC22, IC26 and the "Game ROM" socket at IC14
for holding game software. Using the additional three chips at 
IC21, IC22 and IC26 allowed Firepower to have an extra 1.5K bytes 
of game program (in addition to the 2716/2316 green Flipper ROMs 
at locations IC17, IC20). The original configuration of three 
masked 512 byte ROM chips at IC21, IC22, IC26 and a 2316/2716 at 
IC14 required that CPU board jumper J4 be installed and J3 be 
removed (there were orange labels in the cabinet and on the CPU 
board noting this).

The three masked 512 byte ROMs used in Firepower at IC21, IC22, IC26
are troublesome. In addition, their sockets may need to be replaced. 
A better solution is to use a single 2732 EPROM at U14, eliminating 
all the masked 512 byte ROMs and their sockets! The "Fp_IC14.732" 
ROM data file documented here accomplishes this, but some CPU board 
modifications must be made. Note this modification was originally
designed by Duncan Brown.


SYSTEM6 CPU BOARD MODIFICATIONS FOR USING "Fp_IC14.732" GAME ROM
----------------------------------------------------------------
Note a system6 CPU board modified in the described way will no 
longer work in any other games unless the modifications are undone. 

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 this 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 to the pad 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 cut at IC14 (this brings address line
   A11 to chip 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.  TOM CALLAHAN DOES NOT LIST THIS STEP. IS THIS STEP
   REALLY NEEDED?

6. Install two small-signal diodes (1N914 or 1N4148) at jumper 
   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 chip IC14.  TOM CALLAHAN JUST USES WIRE JUMPERS AT J3/J4.
   ARE DIODES REALLY NEEDED?

7. Program a 2732 with the "Fp_IC14.732" ROM data and install at IC14.
   IF the game doesn't already have working Green-label ROMs at IC17
   and IC20, of course install those too.

In case there is a 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.

END OF SYSTEM6 CPU BOARD MODIFICATION.


SYSTEM7 CPU BOARD NOTES FOR USING "Fp_IC14.732" GAME ROM
--------------------------------------------------------
There is a special file which can be downloaded that 
contains the EPROM software for running Firepower in a
System7 CPU board. Please see http://marvin3m.com/fix.htm
for details.


SYSTEM3/SYSTEM4 CPU BOARD MODIFICATIONS USING "Fp_IC14.732" GAME ROM
--------------------------------------------------------------------
Technically speaking, no System6 game can run in a system3 or 
system4 CPU board. This has to do with the memory protect circuit
and chip select circuits.
