Disclaimer: This information is provided as is. There may be errors in this information. You may use this information only if you agree that Minimalist / Coinop.org, its employees, and noted authors will never be held responsible for any damage, injury, death, mayhem, etc. caused by errors in the information. When working with high voltage, never work alone and always follow safety precautions.

Document Title: [FAQ-Bally Midway MCR Games.html (html file)]

Bally Midway MCR System Games FAQ

                      Bally Midway MCR System Games FAQ

                                 version 1.0

                      Mark Jenison        Clay Cowgill

   I. Introduction
  II. The MCR system classes
      A. CPU's
         1. MCR (I)
         2. MCR II
         3. MCR III
      B. Super Sound I/O
      C. Video
         1. Video Generator II
         2. Video Generator III
      D. Misc
         1. Audio Amps
         2. Cassette mechanisms
         3. Controls
 III. Games
      A. Kick/Kickman
      B. Tron
      C. Satan's Hollow
      D. Tapper
      E. Timber
      F. Discs of Tron
      G. Spy Hunter
      H. Solar Fox
      I. Two Tigers
      J. Journey
      K. NFL
      L. Wacko
  IV. Game to board mapping
   V. Conversion classes
  VI. Related Documents
 VII. Contributors
VIII. Document History

I. Introduction

This document discusses the Bally Midway MCR system games, including MCR,
MCR II and MCR III games.  This system was designed so that many different
types of controllers and external peripherals (such as cassette decks, speech
boards, lights, etc.) could be run on a common platforms.  This platform
consisted of a sound I/O board, a CPU board, and a video generator board, and
the same set of boards (in most cases) could play a different game with just
simple EPROM swaps.

II. MCR System Classes

A. CPU's

1. MCR (I)

The MCR CPU Board (Midway part number A084-91399-A968) is a Z-80 based
microcomputer consisting of EPROM program and graphics memory, general
purpose SRAM, high speed RAM for video, a custom video timing generation
system, and I/O subsystems and decoding.

B. Super Sound I/O

Super Sound I/O Overview:
The Bally Midway Super Sound I/O board is, as the name suggests, the input
and output method for MCR series games, as well as the sound generator.

The SSIO is a Z-80 based computer.  It runs at 2MHz from dividing down a
16MHz clock.  The SSIO has 1K of SRAM, up to 16K of program ROM, access to
over 48 lines of system I/O (buttons and the like), and 2 8910 sound

The SSIO is capable of reading input from both switches (like standard
arcade buttons) and optical quadrature encoders (like a "spinner" knob such
as used by Tempest, Arkanoid, TRON, etc.)

Button inputs are read through 74LS244 data buffers with series resistors,
protective capacitors, and 10K pull-up resistors on all input lines.  Some
boards appear to have been intentionally altered in the field by removal of
the .1uF caps and pullup resistors on the '244s.  (Anyone who knows the
origin and details of this modification is encouraged to send the story to
me!  -- clay@supra.com)

Angle encoder boards (such as TRON's "spinner" knob) are read as parallel
data from either J4 or J6 connections.  Quadrature signals from the knob
are converted to parallel position data on the Angle Encoder Board, so the
SSIO only needs to read the results with no other conversion required.

Game specific settings are accomplished by adjusting one 10 DIP switch
block (SW1).  SW1 contact #10 connects to the *uWAIT line, effectively
pausing the game when in "on" position.

SSIO Built in test mode:
Low level SSIO test options are accomplished through setting on SW3.

           |   SW#1      SW#2      SW#3      SW#4       SW#5-SW#8
Normal     |    OFF
Operation  |
SSIO       |    ON
Diagnostic |
Normal     |              OFF
Operation  |
RAM/ROM    |              ON
Test       |
Normal     |                        OFF
Operation  |
Oscillator |                        ON
Test       |
Normal     |                                  OFF
Operation  |
Filter     |                                  ON
Test       |

For any of the test modes to be operational, SW3/SW#1 must be ON.  To test
RAM/ROM, set SW3/SW#1 to ON, and SW3/SW#2 to ON and power up the board.  A
steady "ON" LED #3 (in the lower left hand corner of the PCB) indicates
proper operation.  A slow blinking LED #3 indicates a RAM error, a fast
blinking LED #3 indicates a ROM error.  LED #3 is normally not lit during
game operation.

[Oscillator and Filter test needs to be documented...]

There is a SW2 block documented in most schematics for the SSIO, but it
appears to not be present on any of the PCB's I've seen.

Differences from game to game:
As alluded to previously, the SSIO is a general purpose I/O board used
across all the MCR series games with minor modifications from system to
system.  As a general rule, the SSIO from different games may be safely
swapped for testing purposes.

Customization of the SSIO for a particular game is accomplished through
four 4K EPROMs in locations A7-A10.  Two jumpers, JW1 and JW2 select
different configurations for either 2732 or 2532 based EPROMs.  Note that
simply swapping EPROMs without examining JW#1 and JW#2 for proper settings
may not work!

For 2532 EPROMs:  JW#1 open (cut), JW#2 present (shunt)
For 2732 EPROMs:  JW#1 present (shunt), JW#2 open (cut)

The number of sound ROMs used in a particular game varies, however they
will always start filling the sockets in A7 to A10 order.  There should be
no "gaps" in the order.  (EPROMs in positions A7 and A9 with an empty A8
for example is probably not correct.)

Some known configurations are listed below:

Game                 Number of ROMs
Spy Hunter                 2
TRON                       3
Solar Fox                  3
Satan's Hollow             3
Two Tigers                 3
Kick                       4

SSIO Sound Generation:
Stereo sound is generated in the SSIO by the use of two AY-3-8910 Sound
Generator chips.  One chip (F7) drives the left channel and one chip (F6)
drives the right. The design of the 8910 is from General Instruments (GI), as
are most production units you see.  Yamaha also produced a pin compatible unit,
the YM2149.  GI is no longer (they are now Microchip Technology, makers of the
PIC series of microcontrollers), but the 8910 can still be had from many
sources such as JDR Microdevices (www.jdr.com).

Each 8910 contains 3 sound generators (which can be coupled with a white
noise source) and two full 8 bit parallel ports, plus some extra I/O lines.
The 8910 was used in the Atari ST series of computers (potential parts
source here :-). 

The Bally Midway engineers did something a bit clever with the trusty old
8910-- they used the extra I/O lines as outputs to control a vibrato/filter
system and a stereo panning system, this results in the SSIO producing
noticeably more interesting effects than a "vanilla" 8910.

The panning system is not present on all boards and is typically found in
MCR III based games like the "environmental" Discs of TRON and sit-down Spy
Hunter.  Versions of the SSIO without panning are usually the
A082-90913-x000 part number.  Versions with panning often appear to be
A080-91657-x000.  Note that the panning boards were apparently used as
"non-panning" boards simply by not stuffing the panning section with parts
and adjusting some part values.  Boards such as the A082-90908-L000 can be
converted to a panning version simply by filling in the missing components
and adjusting some part values.  Do not attempt this without a copy of the

SSIO ROMs for both panning and non-panning versions of a game appear to be
identical. (At least on Spy Hunter, if anyone can verify that for Discs of
TRON I'd appreciate knowing one way or the other!)

Audio amplification is done on a separate Amp board (the "Dual Power Amp"
or "Dual Power Amp with Mixer", and similar parts.  Some games used
additional sound production techniques such as a casette player (Journey),
8-track casette player (Two Tigers),  stand alone music board (Spy Hunter,
the 16MHz 68000 based "Cheap Squeak Deluxe"), and voice synthesis boards
(Discs of TRON, the "Squak & Talk" board).

SSIO PCB numbers and variations:
A082-90913-E000 SSIO, no panning (this seems to be the most common)
A082-90913-G000 Same as above, but includes A3 (74LS273) for 2 players
A082-90908-G000 SSIO, no panning, but has locations for pan components
A082-90908-L000 Same as above, but uses a 74160 instead of a 74190
A082-91657-A000 SSIO, with panning installed (seems to be least common)

Common Failure Points on the SSIO:
The SSIO seems to be a very sturdy design.  Some failures I have encountered:

Bad chip sockets on A6 (RAM) and A7-A10 (ROM). (24pin sockets) **

Some components seem prone to damage by rough handling-- lots of times
470uF electrolytics CP1, CP13, CP47, and CP54 tend to break off.  They just
help keep the +5V levels relatively ripple-free, but replace them anyway if
in doubt. **

According to a StarTech Journal entry, some of the early "Kick" boards had a
flaw where CP34 was inserted with its polarity reversed.  The fix was to
either turn it around or cut it off completely.

The .047uF cap in the audio output section tends to break off sometimes as
well.  (It's usually C139.) **

LED #3 also seems to be missing a lot (broken off).

SW4 (the reset switch to the Z-80) isn't very sturdy either. Sometimes
it'll latch "closed" and cause a constant reset state in the game.  Test it
with your multi-meter.

Very early MCR games used SIPP-style sockets for the J1 and J2 connectors
with solid core wire ribbon cables interconnecting the boards.  If you see
these REPLACE THEM IMMEDIATELY.  They do really, truely, suck. **

Also check for cold solder joints on JP1 and JP2.  Connecting and
disconnecting the cables causes cracking in the old solder and reliability

Do you hate those 24 pin "ribbon" cables as much as I do?  I have a good
trick to replace them-- use a 50 to 50 pin connector (like a SCSI cable)
and go from the top of one header to the bottom of the other.  Remember
that there's one pin left over (the SCSI cable is 25 pins wide-- not 24),
be sure to put the spare pin on the same side on both end of the
connection. (I got a great deal on 3 connector SCSI cable assemblies that
work wonderfully for this, I have extras for sale if you need parts. -Clay)

** (I have these for sale if you need parts. -Clay)

Keep and eye on those DIP switches.  None of SW3's settings should be "on"
during normal operation. Switch 10 on SW1 should always be "off" for normal

D. Misc


Bally Midway's MCR games were special in that most of the games designed
required unique controls.  This developers expanded the controls horizon,
rather than limiting themselves to the simple joystick and button format
of the era.

Bally Midway MCR games had a lot of controls which you don't see often on other
games.  The description of some of these controls follows.

Trigger joystick -
     A joystick which has a button built in.  This design left the player
     with a free hand to work other controls.

Tri-level encoder wheel -
     This is not only an encoder wheel that goes left and right, but can be
     pulled UP or DOWN.  Basically, the encoder wheel is stable, but the shaft
     going through the wheel can be pulled up or down to press either of two
     leaf switches.

Bi-directional trackball (roller) -
     A trackball which had an axis running through it, allowing it to only go
     in two directions.  Basically just a fancy encoder wheel.

Other examples of unique controls includes Spy Hunter's, Two Tigers' and
Tapper's set up.

IV. Games

This is a list of games on the Bally Midway MCR system.  Each entry has a
description of the game and controls it used.

Kick / Kickman

Kick is a game where a man with a pointy hat pedals back and forth on a
unicycle, catching and/or popping balloons on his head.  Some rounds include
Pac-Men, which you can catch to eat the balloons on his head for big bonus
points.  If something you wanted to catch on your head drops too fast and gets
buy you, you can kick it back up in the air (if you are close enough).  If the
falling object hits the ground, your unicycle falls over, and you lose a turn.
There are bonus rounds where you can pop balloons that are being thrown from
windows.  The same people are also throwing bombs, which you must avoid.

Kick was later changed to Kickman (hoping to draw in the Pac-Man crowd, I
suppose).  The change from one to the other was minor; the marquee changed,
the bonus rounds changed somewhat, and the CPU and video board changed.

Kick/Kickman used a "mirrored" screen where the video displayed on the monitor
is actually reflected up by a mirror.  If you play directly on a monitor,
everything will be a "mirror image" of what it should be, including the
bi-directional trackball.

Controls: Bi-directional trackball, Kick, 1P, 2P buttons


Remember the movie TRON?  Well, Bally Midway had two design teams competing
internally (although one was apparently set-up as a contractor) for the Tron
contract.  One team went with a very cool vector game based on new technology.
The other designed five games to be grouped together and played on the existing
Bally Midway MCR hardware.

The vector game was seen as having possible delays, and due to the fact that
the game *had* to be completed by the time the film premiered, the other team
got the job.  Due to hardware and time constraints, it was decided that one of
the games should be removed from the TRON game, possibly for a sequel...

Controls: Trigger joystick, encoder wheel, 1p and 2p buttons

Discs of Tron

This was the fifth game that was supposed to be in Tron, but was moved off and
later made into this excellent sequel.  In this game, your object is to throw
discs at Sark in an attempt to knock him off his disc(s) before he knocks you
off yours.

This game came in a dedicated upright, a Tron conversion, or the infamous
"environmental" cabinet.  This cabinet was made to STAND in.  Unlike the
uprights, the environmental (or booth) version had speech effects, along with
surround sound and a lot of lighting effects.  And for the record, the
environmental cabinet CANNOT be dismantled for ease of transportation; 

Controls (environmental): Trigger joystick w/thumb button,
                          tri-level encoder wheel, start game
Controls (upright): Trigger joystick w/thumb buttons, tri-level encoder wheel,
                    1p and 2p buttons.

There is a ROM difference between the upright and environmental games.
The main difference between these two were:

1) The upright had no speech, special audio effects, or lighting effects
2) On the upright version, it displayed during the demo the points awarded
   awarded for derezing a disc
3) The upright could support two player games

Solar Fox
The player controls a space ship with the purpose being to "clear the
playfield" of targets either by shooting them or running them over.  There
are enemy turrets moving back and forth on each wall around the perimeter of
the grid that shoot at you.  They can be STUNNED, but not killed.  There also
some bad guys in the arena with you.  There is a timer, and if you clear the
screen with time left, then there is a bonus score added.

Controls: Trigger joystick, a "fast" button, 1p and 2p buttons.

Two Tigers

Air-sea battle game.  You fly a plane which is attacking a battleship.  The
object is to put holes in the ships hull by using bombs and by causing
enemy planes to crash into it.

In a two-player game, you can either play with or against the other player.  If
you play against the other player, you must first have a dog fight.  Whoever
wins the dogfight gets first shot at the other players ship, and you alternate
attacking and defending each others ship.

There were different configurations for this game.  The dedicated cabinet had
flight yoke controls, whereas the Tron conversion had encoder wheels.  Fire
and bomb buttons, 1P and 2P buttons.

Satan's Hollow

You are pitted against Satan himself!  The ultimate battle between evil and...
technology?  Your ship must fight off waves of attacking demons while
attempting to build a bridge to the devil himself!

Controls: Trigger joystick, 1p and 2p buttons.


You control a lumberjack who must cut down his quota of trees to make the boss
happy.  There are bonus rounds where you must balance on floating log for

Controls: joystick for movement and a two-way joystick for choppig, 1p, 2p

Spy Hunter

This game is best known for it's dramatic "Peter ???" sound track that played
during the game.  You are a spy, driving a James Bond type car which is fully
equiped with machine guns at the start.  Bad guys in black cars will try to
stop you by shooting at you, bombing you, slashing your tires, or knocking you
off the road.  Fortunately, a semi (or a mobile car workshop) will come by from
time to time to give you additional weapons to fight these bad guys, such as
smoke screens, oil slicks, or ground-to-air missiles.

Controls:  A flight yoke type steering wheel).  A trigger
           and thumb button for each side, and a yellow button in the middle
           which called the truck when flashing.  Also a start buttons and
           high low shifter.


A laser-disk football game.

From Mike Treu's Laser FAQ part 2

From what I've gathered; so far, you play coach and select plays with
real NFL teams.  The control panel has two sets of 6 buttons (one for each
player), that ues little half football dividers, so the other player
cannot see your decisions; and there is a star button (throws a
star-player in the game).  That's all I know.

From David Shuman's LaserHead FAQ 0.4

Game using real NFL footage. 

From what I've gathered; so far, you play coach and select plays with real NFL
teams. The control panel has two sets of 6 buttons (one for each player), that
uses little half football dividers, so the other player cannot see your
decisions; and there is a star button (throws a star-player in the game).
That's all I know. 

RCA SJT-400 video-disc player. (It's an IEEE interface ?). This is not a
standard laser disk. 


The only game based on a super group from the '80s!  Based on the Journey
Escape album, you control each of the four band members, each whom have to
retrieve their lost items on a specific screen.

Neil Schon  - must use his jet pack to navigate a cavern to get his guitar
Jonathan Cain - must work his way downscreen while jumping over barriers.
Steve Perry - must walk through swinging gates to get his microphone
Ross Valory - must retrieve his bass guitar and avoid flying records.
Steve Smith - must bounce his way across the screen of drums to his drum set.
              After he uses a drum to bounce, it disappears.

When all four members have retrieved their items, they hold a concert!  As a
security guard, you must keep the crowd from reaching the stage for extra
bonus points!  Once the fans reach the stage, the four must retrieve their
items once again.  

During each screen, a specific Journey song is played.  This is one of the
games which used the infamous cassette tape mechanism for music. 

Chris Smith (cjsmith@amoco.com) is working on a more detailed Journey FAQ.

Controls: joystick, 1p, 2p and action buttons.

Domino Man

You must set up a chain of dominos on the screen while keeping
people and objects from knocking it down.  Set up the entire chain (as
displayed by dots on the ground) and you finish the round.

Controls: joystick, place button, 1p and 2p buttons.


You are a bartender who must serve all thirsty customers before they get to the
end of the bar.  Toss a frosty one down the bar to oncoming patrons.  Pick up
tips for extra points.  Customers return mugs by sliding them back down the
bar.  Catch the empty mugs before they slide off the bar and break!

There were two versions of Tapper: Rootbeer Tapper and Tapper.  Both were
produced side by side, with Rootbeer Tapper geared to the arcades and Tapper
geared towards bars/taverns.  The Tapper cabinet has brass-like drink holders,
foot rest and promoted Budweiser.

Controls: joystick, and tapper handle


You are in a spaceship and must shoot two alike space creatures
to destroy them (one shot stops it, and if the next shot hits it's match,
both are destroyed.

Controls: Trigger joystick, 1p, 2p

IV. Game Board Mapping

X - all versions
U - upright only
S - special (sitdown or booth)

     board|| MCR   | MCR II|MCR III|| SSI/O || MCR II|MCR III|
          || CPU   | CPU   | 5MHZ  || (PAN) || Video | Video |
Game      ||       |       | CPU   ||       ||  Gen  |  Gen  |
Solar Fox ||   X   |       |       ||   X   ||   X   |       |
Kick      ||   X   |       |       ||   X   ||   X   |       |
Tron      ||       |   X   |       ||   X   ||   X   |       |
Timber    ||       |   X   |       ||   X   ||   X   |       |
Kickman   ||       |   X   |       ||   X   ||   X   |       |
S. Hollow ||       |   X   |       ||   X   ||   X   |       |
Two Tigers||       |   X   |       ||   X   ||   X   |       |
Wacko     ||       |   X   |       ||   X   ||   X   |       |
Domino Man||       |   X   |       ||   X   ||   X   |       |
Discs/Tron||       |       |   X   || U,(S) ||       |   X   |
Tapper    ||       |       |   X   ||  (X)  ||       |   X   |
Journey   ||       |       |   X   ||   X   ||       |   X   |
Spy Hunter||       |       |   X   || U,(S) ||       |   X   |
NFL       ||       |       |   X   ||   X   ||       |   X   |

V. Conversion Classes

The following can be converted from one to the other with EPROM swaps:

a) TRON, Timber, Kickman, Satan's Hollow, Two Tigers, Wacko

b) Spy Hunter, Tapper, Discs of TRON

VI. Related Documents

1. Journey FAQ 
   (unreleased as of this posting)
2. Tapper pinouts (wiring compatible for most all MCR games)

VII. Contributors

Clay Cowgill 
Mark Jenison 
Rick Schieve 
Christopher T. Kuntz <73543.3174@compuserve.com>
Bill Esquivel 
Greg Kam 
Al McCormick 
John Morrison 
Gaymond Lee 
Chris Smith 
Jeff Peters 

VIII. Document History

Version 1.0: Initial release