Midway 8080 System Boards
The motherboards are nearly functionally identical but come in several basic variations. PC 80-90000-A000 & PC 80-90000-L000 are the last of the series commonly found on Space Invaders and Space Encounters. Revision L000 has 28 pin EPROM socket setup but is used in the 24 pin configuration. The A000 and L000 revision boards also have a 7432 chip near the daughter board connector not found on the earlier boards. Earlier boards I know of are 80-900E, F or H. The layout is slightly different, crystal is in different location & appears that the ROM jumpers may be different. The motherboards are switch able from game to game but the daughter board (Audio, I/O port) is unique to each game, some even have a different board for cocktail vs upright of the same game. Most of the daughter boards can be identified by the circuit board etching with the game name. Some are not as obvious, who would recognize M4 as a game and not a code?
Sophisticated for it's day it could produce 224 horizontal lines by 256 blocks.
Space Invaders did not include a RAM test for Midway 8080 boards since it was licensed from Taito and part of the agreement was no alterations to the code (i.e. test mode). The Ram Tester P.C. 80-903 can be used to test the RAMs (from service bulletin 10/10/78).
Note that originally the 2716 used on these games were TMS2716's (Texas Instruments) which use 3 voltages and are not compatible with other 2716's.
To activate test, set dips as indicated and hit coin door tilt to start test.
The number under 2716 is the quantity of 2716 EPROM's (or 9316 proms) that should be used on the board.
*1 - Space Invaders did not include a RAM test for Midway 8080 boards since it was licensed from Taito and part of the agreement was no alterations to the code (i.e., test mode). The Ram Tester P.C. 80-903 can be used to test the RAMs (from service bulletin 10/10/78).
Note: the original 2716s used on these games were TMS2716's (Texas Instruments) which use 3 voltages and are not compatible with other 2716's.
Space Invaders Cocktails
Game logic boards A084-90700-739 B & C are used in uprights only.
Game logic boards A084-90700-739 D & E can be used in uprights & table models. All jacks are keyed and will plug in properly.
- From Bulletin 3/5/79
Shuffleboard / Space Invaders
H is strapped for 2716's Only.
-from Bulletin 10/9/78
Due to a supply problem the 25S10 shifter IC's have been replaced with 74151 Data selector multiplexers.
PC A084-90700-B000 Have (4) 25S10's.
-from Bulletin 12/11/78
Old method of play, new method of play.
-from Bulletin 2/78
Mother Board PC 0080-00-900G
New motherboard has been altered due to the need of additional 16K Prom capability and cannot be used in earlier processor games. The Extra Innings motherboard is marked 2X & PC 0080-00-900G.
Note: 16K Roms in B, E, F, G, and H. No Roms in C or D.
Games that are not a part of the Midway 8080 system:
Last updated July 10, 2003
Saved to www.brentradio.com for archival purposes. All credit to the above people.