Space Duel to Gravitar conversion (long)

From: tom mcclintock <tomm_at_mgcap.com>
Date: Wed Mar 29 2000 - 15:13:34 EST

I got my Gravitar board working inside my Space Duel cabinet, and
thought I would share the information on how to do it. I do have a
couple of extra AMP connectors and pins if someone has trouble finding
them and wants to make one. Just drop me an e-mail.

If anyone has anything to add or comments, please let me know.

tm

-----------------------------------------------------------------
| CONVERSION BETWEEN SPACE DUEL AND GRAVITAR |
-----------------------------------------------------------------

COPYRIGHT 2000

REVISION NUMBER: 1.0 (first public release)
  REVISION DATE: 29 March 2000
     CREATED BY: John Lee and amended by Tom McClintock

PART I: Conversion of A Space Duel Control Panel to Gravitar
PART II: Gravitar Control Panel In A Space Duel Cabinet
PART III: Other Helpful Space Duel/Gravitar Information

STANDARD DISCLAIMER:
--------------------
REMEMBER, NO WARRANTEES, EXPRESS OR IMPLIED, ARE GIVEN. USE THIS
INFORMATION AT YOUR OWN RISK. I AM NOT RESPONSIBLE FOR ANY DAMAGES
THAT MAY OCCUR TO YOUR PERSON OR PROPERTY.

-----------------------------------------------------------------------
PART I.
CONVERSION OF A SPACE DUEL CONTROL PANEL TO GRAVITAR
  by: Tom McClintock
-----------------------------------------------------------

GENERAL OVERVIEW:
-----------------
Having an Atari Space Duel cabinet and an extra Atari Gravitar PCB, I
proceeded to come up with a simple and non-invasive way to play
Gravitar in my Space Duel cabinet. Since Space Duel and Gravitar share
almost identical control panel layouts (aside from the fact that
Space Duel has two sets of controls while Gravitar has only one),
Gravitar can be easily incorporated into the cabinet with a small
control panel adapter harness.

The Space Duel cabinet wiring harness is pin compatible with a
Gravitar PCB, but the Gravitar PCB looks for player inputs on different
pins than what the Space Duel control panel provides. So, a small
conversion harness must be inserted between the Space Duel control
panel and the Space Duel wiring harness to send the correct signals
to the Gravitar PCB. The Gravitar game PCB requires no alterations
with this conversion. I chose the Player 2 controls on the Space Duel
panel to act as the controls for Gravitar as they get used less
frequently. If you are so inclined, it is just as easy to map the
Player 1 controls to play Gravitar. The Start Switch becomes "Player 1
Start" and the Select Switch becomes "Player 2 Start". The "Shields"
button also acts as the Tractor button - exactly as the original
Gravitar control panel layout. The wires on the Space Duel control
panel harness that are not explicitly listed are not connected.

INGREDIENTS:
------------
1 - Working Gravitar Board
1 - AMP 24-pin Miniature Rectangular Pin Housing (AMP# 1-640515-0)
1 - AMP 24-pin Miniature Rectangular Socket Housing (AMP# 1-640525-0)
13 - AMP MR Live Split pins (or equivalent)
13 - AMP MR Standard Socket pins (or equivalent)
13 - Three-inch segments of 20 gauge insulated wire

[note: please check the AMP web site for distributors www.amp.com ]

HARNESS CONSTRUCTION:
---------------------

<------------------------------------------>
Space Duel to Gravitar Conversion Harness
   using Space Duel Player 2 controls

Space Duel CP Space Duel Harness
        pin 1 to pin 11
        pin 2 to pin 9
        pin 3 to pin 3
        pin 4 to pin 14
        pin 5 to pin 5
        pin 6 to pin 13
        pin 7 to pin 7
        pin 13 to pin 6
        pin 14 to pin 4
        pin 21 to pin 21
        pin 22 to pin 22
        pin 23 to pin 23
        pin 24 to pin 24
<------------------------------------------>

TROUBLESHOOTING:
----------------

 - Check the continuity on each harness wire before inserting it into
   the AMP connector. This is obvious, but sometimes overlooked.

 - Before you insert each wire into its respective AMP connector,
   carefully note the male/female orientation of the pre-existing
   Space Duel harness(es). If a button is not working or is operating
   a different feature, then check proper pin-to-pin connections.

 - Try to make the conversion harness as short as possible to eliminate
   any unnecessary bending of the Space Duel cabinet harness.

 - The Space Duel PCB treats "Rotate Left" and "Rotate Right" in an
   opposite way to the Gravitar PCB. Therefore, the adapter harness
   inverts the left and right rotation for Gravitar. This will only
   make sense if you are reviewing the pinouts - otherwise do not worry
   about it.

 - The self test routines for a Gravitar PCB are the same as for a
   Space Duel PCB with one difference. While Space Duel utilizes the
   SLAM switch to step through the self test screens, Gravitar uses the
   aux coin switch mounted next to the coin counter.

-----------------------------------------------------------------------
PART II.

GRAVITAR CONTROL PANEL IN A SPACE DUEL CABINET:
   by John Lee (jhlee@hac2arpa.hac.com)
-----------------------------------------------------------

The following describes how to connect an Atari Gravitar control panel
to the Atari Space Duel cabinet harness. Both the Gravitar control
panel and game PCB are virtual drop-in substitutes into the Space Duel
cabinet. However, while the Gravitar panel has a 12-pin Molex-type
connector, Space Duel uses a 24-pin AMP connector [# 1-640515-0].

In my own conversion, I made a small adapter that plugs in between the
Gravitar control panel and the Space Duel harness. With this adapter,
no alterations are made to the harness or control panels and it is
easy to switch between the games. The Gravitar game PCB requires no
alterations.

The wires on the Space Duel harness that are not explicitly listed are
not connected. The pin numbers given are for connector J24/P24 on
both game's schematics (the connector at the control panel.) For your
reference, the wire colors are included below.

HARNESS CONSTRUCTION:
---------------------

<------------------------------------------>
Space Duel to Gravitar Conversion Harness
     using a Gravitar Control Panel

  Gravitar CP Space Duel Harness
        pin 1 to pin 13
        pin 2 to pin 7
        pin 3 to pin 3
        pin 4 to pin 9
        pin 5 to pin 14
        pin 6 to pin 5
        pin 7 to pin 11
        pin 8 to pin 6
        pin 9 to pin 4
        pin 10 to pin 21
        pin 11 to pin 23
        pin 12 to pin 24
<------------------------------------------>

-----------------------------------------------------------------------
PART III.

OTHER HELPFUL SPACE DUEL/GRAVITAR INFORMATION:
----------------------------------------------

                   SPACE DUEL PINOUTS

                          P20
                        _______
                    GND |A | 1| GND
                    +5V |B | 2| +5V
                        |C | 3| +22V
                        |D | 4| -22V
                 +10.3V |E | 5|
                Lockout |F | 6| Coin Counter Right
      Coin Counter Left |H | 7| Select LED
              Start LED |J | 8| Rotate Left 2
         Rotate Left 1 |K | 9| Shield 2
               Shield 1 |L |10| Thrust 1
               Thrust 2 |M |11| Select Switch
             Switch GND |N |12| Switch GND
             Switch GND |P |13| Switch GND
                        |R |14| SLAM Switch
              Coin Aux. |S |15|
              Self Test |T |16| Coin Switch Left
      Coin Switch Right |U |17|
                        |V |18|
                        |W |19|
                        |X |20|
                    +5V |Y |21| +5V
                    GND |Z |22| GND
                        -------

                          P19
                        _______
                  X OUT |A | 1| X GND
                  Y OUT |B | 2| Y GND
                        |C | 3| Fire 1
                        |D | 4| Fire 2
         Rotate Right 2 |E | 5| Rotate Right 1
                        |F | 6| Start Switch
                Red GND |H | 7| Red
              Green GND |J | 8| Green
               Blue GND |K | 9| Blue
                        |L |10|
              Audio GND |M |11| Audio 2
                        |N |12| Audio 1
                        -------

--------------------------------------------------

                    GRAVITAR PINOUTS

                          P20
                        _______
                    GND |A | 1| GND
                    +5V |B | 2| +5V
                        |C | 3| +22V
                        |D | 4| -22V
                 +10.3V |E | 5|
                Lockout |F | 6| Coin Counter Right
      Coin Counter Left |H | 7| Player 1 LED
           Player 2 LED |J | 8|
                        |K | 9|
                        |L |10| Coin Switch Left
                Start 1 |M |11| Start 2
             Switch GND |N |12| Switch GND
             Switch GND |P |13| Switch GND
                        |R |14| SLAM Switch
              Coin Aux. |S |15|
              Self Test |T |16| Coin Switch Left
      Coin Switch Right |U |17|
                        |V |18|
                        |W |19|
                        |X |20|
                    +5V |Y |21| +5V
                    GND |Z |22| GND
                        -------

                          P19
                        _______
                  X OUT |A | 1| X GND
                  Y OUT |B | 2| Y GND
                        |C | 3| Shields
                        |D | 4| Fire
            Rotate Left |E | 5| Rotate Right
                        |F | 6| Thrust
                Red GND |H | 7| Red
              Green GND |J | 8| Green
               Blue GND |K | 9| Blue
                        |L |10|
              Audio GND |M |11| Audio 2
                        |N |12| Audio 1
                        -------

--------------------------------------------------
       SPACE DUEL CONTROL PANEL PINOUTS
                
           pin color function
           --- ---- ----------
           1 W-Bk Shields 2
           2 W-Bn Rotate Left 2
           3 W-R Rotate Right 2
           4 W-Or Thrust 2
           5 W-Y Fire 2
           6 W-Gn Select LED
           7 W-Bu Select Switch
           8 W-V Rotate Left 1
           9 W-Gy Rotate Right 1
           10 Bn Thrust 1
           11 Or Fire 1
           12 Gn Shields 1
           13 Bu Start LED
           14 V Start Switch
           15 unused
           16 unused
           17 unused
           18 unused
           19 unused
           20 unused
           21 Bk Switch GND 1
           22 Bk Switch GND 2
           23 R +5V
           24 Gn GND

--------------------------------------------------
        GRAVITAR CONTROL PANEL PINOUTS
                
           pin color function
           --- ---- ----------
           1 W-Bk Start 2 LED
           2 Bu Start 2 Switch
           3 W Rotate Left
           4 O Rotate Right
           5 Y Thrust
           6 Gn Fire
           7 Bu Shields
           8 V Start 1 LED
           9 Gy Start 1 Switch
           10 Bk Switch GND
           11 R +5V
           12 Gn GND

---------------------------------------------------------
Color Key:
    Bk Black Gy Gray V Violet
    Bu Blue O Orange Y Yellow
    Gn Green R Red W White
    Bn Brown

Colors such as "W-Bk" indicate "solid_color-stripe_color"
(in this case, a white wire with a black stripe.)

---------------------------------------------------------

from Jess Askey:
If you look at the edge connector on the [Gravitar] PCB you will see
that the +5V pins and the 'sense' pins are the same. The purpose of
the sense pins is to provide a very low current path from the +5V on
the PCB back to the power supply. Because the path is low current, the
possibility of a voltage drop across the pin connection and wire is
extremely small, whereas the potential for a voltage drop across the
pin connection on the main +5V wire is much greater. That way, if there
is a perfect 5.00V coming out of the Aud/Reg II board and there is a
voltage drop of .25V on the main +5V pins, that would put 4.75V on the
game PCB, the sense wire sends this voltage back to the Aud/RegII board
and it compares it to a reference of +5V. Since it is low, the Aud/Reg
II board will theoretically put out a new adjusted voltage of 5.25V so
that with the voltage drop taken into consideration, the PCB now has
a perfect 5.00V as it should.

Sorry for the long-winded explanation. Basically, you can see if you
look at the PCB pinouts, the symmetrical connection pattern of the
power supply pins. You can even plug it in backwards and the way Atari
made it, you most likely will not do any damage! Nice!

Just for clarity... the only main difference between Space Duel and
Gravitar hardware is the existence of Linear Scaling on Gravitar
(not counting that the memory map is a bit different).

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| END |
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Received on Wed Mar 29 15:44:04 2000

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