-----------------------------cut here--------------------------------------- The following documents what is necessary to convert a Gravitar (GRAV), Space Duel (SD) or Black Widow (BW) to play Major Havoc (MH). Last Modified: Feb 22 1994 STANDARD DISCLAIMER: The author hereby grants 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 author only and not necessarily those of his employer. This document is provided for informational purposes only. Although every effort has been made to provide accurate information, the usefulness of any of the information contained herein cannot be guaranteed due to the complexity of the issues involved. The author takes no responsibility for anything arising as a result of using the information provided herein, and the reader hereby absolves the author of any and all liability arising from any activities resulting from the use of any information contained herein. NON STANDARD DISCLAIMER: Get at a minimum the pinouts for the respective games. I'd strongly suggest you also get a copy of the game wiring diagram (part of the schematics). Cross check the pinouts below with the wiring diagrams, before powering on. -------------- 1. The game board ----------------- Atari released Major Havoc in three varieties. As a dedicated cabinet, similar to that used for I Robot (maybe even the same) As a conversion for Tempest. As a conversion for Space Duel, Black Widow and Gravitar. All three boards should be the same, using a small daughter board containing 4 IC's and labelled "Quad Pokey". If your board is not like this, DO NOT PROCEED. The two conversions came with a adaptor board. If you have access to the official Atari SD/BW/GRAV to MH adaptor, you have no need to read this. If not, you'll have to make your own, so read on. 2. Atari adaptor boards. ------------------------ The official Atari adaptor board moved X deflection adjustment off the main pcb and onto the adaptor board (if anyone knows why, please let me know). The following document will not attempt to do this, X adjustment will remain on the game pcb. ****** IMPORTANT ****** To allow the X adjustment to take place on the adaptor pcb, Atari cut P19 M/N from ground, and jumped M/N to the legs of two ICs in the vector generation circuitry. If these two jumpers are present on your board, you MUST REMOVE THEM (desolder both ends, and pull the wire off the board) BEFORE CONTINUING. If your board, does not have the jumpers, it was probably used in a dedicated MH cabinet. If you remove the jumpers, this board will no longer work with an official Atari adaptor, unless you reconnect the jumpers. *********************** There are probably 1001 ways to make an adaptor, I used the method described in Rick/Steve's Gravitar2Tempest conversion document, namely: GAME-HARNESS (P20): PCB:E/C1:wiring:E/C2 :MH-BOARD GAME-HARNESS (P19): PCB:E/C3:wiring:E/C4 :MH-BOARD 'E/C' are the edge connectors. You will need 4 total (two 24pin [E/C 3,4] and two 44pin [E/C 1,2]). 'pcb' is a male-to-male .156" spacing board. They are obtainable as '.156" finger boards' from Louise's Harness Shop (1 800 365 1941) for $2 each. 'wiring' is the crossover wiring used to adapt the signals. For more details, see the Gravitar2Tempest document. 3. Adapted lines ---------------- The two games require much the same signals, just not on the same pins of the edge connectors. Therefore you need to adapt the signals, this corresponds to 'wiring' above. Using different coloured wires, and strong wire at the edges (20 gauge) is a good idea. Remember that the harness numbers below are what is displayed on the harness edge connectors. The numbers on EC 1,3 will be reversed and should not be used as a reference. Line MH Harness ---- -- ------- P20 P20 +5V RTN 1/A 1/A (wire both lines) +SENSE 21 21 -SENSE 22 22 +5V REG 2/B 2/B (wire both lines) +22V DC X 3 -22V DC W 4 10.3 UNREG E E SW GND (UTIL) N N SW GND (COIN) 12 N SW GND (CNTL) Z 12 +5V Y Y TEST F T COIN L 7 16 COIN R 6 U COIN AUX K S CTRL L S H CTRL R T 6 P20 P19 AUDIO 1 8 12 AUDIO 2 9 11 AUDIO 1 GND 11 M AUDIO 2 GND M M P19 P19 RED 4 7 GREEN 6 8 BLUE 8 9 RED GND D H GREEN GND F J BLUE GND J K X OUT 9 A Y OUT L B X GND K 1 Y GND 10 2 P20 FIRE L *1 *2 SHIELD P *1 *2 DIR 16 *1 CLR U *1 LIGHT R *3 4. Notes --------- *1: Wire to the controls of your choice. I used a Gravitar panel, installed an encoder wheel in place of the button, and connected it to wires from and as follows: MH GRAV Encoder Ground -> Ground Encoder +5V -> Jumped from Start2 +5V Encoder CLR -> (P19-3) Encoder DIR -> (P19-6) I connected Fire and Shield to Rotate Left and Right as follows: MH GRAV Fire(P20-L) -> Rot R(P19-5) Shield(P20-P) -> Rot L(P19-E) For Space Duel, pick equivalents. For Black Widow, you will need to drill at least one extra hole, and obtain some leaf switches. *2: Fire and Shield are used to start a game. Optionally make additional parallel connections to Start1/2 MH GRAV/BW FIRE(P20-L) -> Start1(P20-M) SHIELD(P20-L) -> Start2(P20-11) MH SD FIRE(P20-L) -> Start(P19-6) SHIELD(P20-L) -> Select(P20-11) *3: Start1/Start2 LED's may be wired in parallel to the encoder light. Be sure to wire a 150 ohm resistor in series on each line. MH GRAV/BW/SD LIGHT(P20-R) -> (-150ohm->P20-7, -150ohm->P20-J)