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Document Title: [GravitarToTempest.txt (text file)]

      -------------------------------------------------------
      | Adapter to plug Tempest board into Gravitar harness |
      -------------------------------------------------------

Copyright 1993 (last update: 2/94)

STANDARD DISCLAIMER: The authors hereby grant permission to reproduce and
distribute this document for personal use, subject to the condition that
the document (along with any copyright and disclaimer notices) is not
modified in any way.  The opinions expressed within this document are
those of the authors only and not necessarily those of their respective
employer.  This FAQ is provided for informational purposes only.  Although
the authors have made every effort to provide accurate information, they
cannot guarantee the accuracy or usefulness of any of the information
contained herein due to the complexity of the issues involved.
The authors take no responsibility for anything arising as a result of
anyone using the information provided in this FAQ, and the reader hereby
absolves the authors of any and all liability arising from any activities
resulting from the use of any information contained herein.


GENERAL OVERVIEW:                           (where ------  are wires       )
-----------------                           (                              )
                                            (      ______                  )
            /-----|___|---\   /---|         (      ______  are male to     )
GRAVITAR   /------|___|----\ /----|         (      ______  male connectors )
WIRING------------|___|-----------|         (                              )
HARNESS    \------|___|----/ \----|         (         |    are female      )
            \-----|   |---/   \---|         (         |    edge connectors )
                                            (         |                    )
                  ^ ^ ^  ^  ^  ^  ^
2 female edge     ^ ^ ^  ^  ^  ^  ^    2 female edge connector that compose the
connector of the  ^ ^ ^  ^wires^  ^    translator part of the adapter - Tempest
Gravitar wiring   ^ ^ ^  ^that ^  ^----board side
harness-----------^ ^ ^ translate     
                    ^ ^                2 female edge connector that compose the
2 male to male PCB--^ ^----------------translator part of the adapter - Gravitar
                                       harness side

This tech tip only addresses the part of the adapter from the "2 female edge
connector that compose the translator part of the adapter - Gravitar harness
side" to "2 female edge connector that compose the translator part of the
adapter - Tempest board side".

The "male to male PCB"s are merely pieces of PCB with straight traces from
"2 female edge connector of Gravitar wiring harness" pins to "2 female edge
connector that compose the translator part of the adapter - Gravitar harness
side" corresponding pin right across from it.  The purpose of the "male to male
PCB"s are only to connect the two connectors....no translation occurs here!





DETAILED INFORMATION:
--------------------

NOTE: Before we start, we need to mention that for a 44 pin female edge
connector (like P20 below), there will be 22 pins on each side.  One side will
be labelled with letters (such as P20-A) and one side will be labelled with
numbers (such as P20-1).  Some letters are not used as labels.

So to construct the adapter all you need (besides the "male to male PCB"s
mentioned in the last paragraph) is a 24 pin female edge connector (P19) and a
44 pin edge connector (P20) to act as the "2 female edge connector that compose
the translator part of the adapter - Gravitar harness side" and a 30 pin edge
connector (P18) and a 44 pin edge connector (P20) to act as the "2 female edge
connector that compose the translator part of the adapter - Tempest board side".
Yes, I realize P20 was listed twice, but it'll be clear in a minute.  Oh yeah,
and you'll need ALOT of wire, preferably different colors! We assume you already
have the Gravitar wiring harness...

Now we are ready to begin.....

                      GRAVITAR   |   TEMPEST
                        SIDE     |    SIDE

               -------------------
               |                 |
               |             P20 |
               |             ----|
               | +5V RETURN  | A |-----------------------P20-1,Z,A;P18-1,A,15,S
               | - SENSE     | 22|_______________________ /   and P20-22,Z
               | + SENSE     | 21|----P20-22,Z?incorrect?/
               | +5V REG     | B |----P20-B,2,V;P18-2,R /
               | +5V REG     | 2 |__/                  /
               | +22V DC     | 3 |----P-20-3;P18-3    /
               | -22V DC     | 4 |----P-20-4;P18-4   /
               | +5V RETURN  | 1 |__________________/
               |             |   |
               |             |   |
               | SW GROUND   | N |----P18-S
               |             |   |
               |             |   |
               |             |   |
               | PLAYER 2 LED| J |----P18-13
               | START 2     | 11|----P18-M
               |             |   |
               | 10.3V UNREG | E |----P20-14
               |             |   |
               |             |   |
               |             |   |
               | PLAYER 1 LED| 7 |----P18-12
               | START 1     | M |----P18-11
               | SW GROUND   | 12|NO CONNECT
               | +5V         | Y |----P18-R
               | LOCKOUT     | F |NO CONNECT
               | COIN L      | 10|----P20-6
               | COIN R      | U |----P20-E
               | COIN AUX    | S |----P20-5
               | CNTR L      | H |----P20-12
               | CNTR R      | 6 |----P20-P
               | SELF TEST   | T |----P20-7
               |             ----|
               |                 |
               |                 |
               |             P19 |
               |             ----|
               | AUDIO 2     | 11|----P18-D
               | AUDIO 1     | 12|----P18-5
               | AUDIO GROUND| M |----P18-E
               | ROT LEFT 1  | E |----P18-9
               | ROT RIGHT 1 | 5 |----P18-10
               | THRUST 1    | 6 |NO CONNECT
               | FIRE 1      | 4 |NO CONNECT
               | SHIELDS 1   | 3 |NO CONNECT
               | Y GROUND    | 2 |----P20-16
               | X GROUND    | 1 |----P20-U
               | Y OUT       | B |----P20-T
               | X OUT       | A |----P20-17
               | BLUE GROUND | K |__
               | GREEN GROUND| J |--\_P20-M
               | RED  GROUND | H |__/
               | BLUE        | 9 |----P20-9
               | GREEN       | 8 |----P20-L
               | RED         | 7 |----P20-10
               |             ----|
               -------------------


NOTE: connections between the following Tempest pins must be made:
           P20-V to P18-F
           P20-J to P20-15
           P20-K to P20-S
      these can be most easily done by wrapping wires around from
      the female edge connector of the adapter (Tempest board side)
      back to the same connector.



MORE NOTES:
1) COIN AUX button on Gravitar is connected to SLAM on Tempest

2) Put spin wheel in fire button hole...below is a diagram of the
   Gravitar control panel

             FIRE    ZAP                    SPIN WHEEL
              |       |                      |
              V       V                      V
              _       _             _        _ 
             /L\     /R\           /T\      /F\
             \_/     \_/           \_/      \_/

                            _  
                           /S\  
                           \_/

   As you can see Gravitar's Thrust and Shield are unused by Tempest.

3) Encoder wheel connects directly to Tempest connector pin 1 to P18-J,
   pin 4 to P18-H, pin 2 to P18-R and pin 3 to P18-S.


CREATED BY: Rick Schieve (3/8/93).
TYPED/EDITTED BY: Steve Ozdemir (3/13/93)

}