Midway Pac Man Troubleshooting Logic Board Part 1 General Instructions

                       METHOD OF PLAY
SW. #1SW. #2
OFF ON1 COIN1 PLAY
ON OFF1 COIN2 PLAY
OFF OFF2 COINS1 PLAY
ON ONFREEPLAY
                      NUMBER OF PACKMEN PER GAME
SW. #3 SW. #4
ON ON 1 PACKMAN
OFF ON 2 PACKMEN
ON OFF 3 PACKMEN
OFF OFF 5 PACKMEN
                                     BONUS PACKMEN
SW. #5SW. #6
ON ON BONUS PACKMAN AT 10,000
OFF ON BONUS PACKMAN AT 15,000
ON OFF BONUS PACKMAN AT 20,000
OFF OFF NO BONUS
SW. #7SW. #8
OFFOFFPLAY MODE
ONOFFRACK TEST
OFFONLOCKS PICTURE
          MO51...

PAC – MAN
TROUBLE SHOOTING LOGIC BOARD PC A082-91375-A000
1. CHECK +5VDC AT CPU AND ROMS.
2. RESET LINE PIN #26 OF CPU NORMALLY HIGH AND GOES LOW WITH RESET.
3. 6MHZ CLOCK FREQUENCY AT PIN #13 OF 8-B AND 3MHZ AT PIN #6 OF CPU.
4. CHECK ROM TEST FOR A MEMORY FAILURE.
5. CHECK ALL ADDRESS AND DATA LINES AT CPU.
6. CHECK ALL ADDRESS AND DATA LINES AT 4-A AND 7-F COLOR PROMS.
7. CHECK ALL ADDRESS AND DATA LINES AT 5-E AND 5-F CHARACTER ROMS.
8. WHEN CHARACTER ROM 5-E IS REMOVED GAME PLAYS BUT MAZE IS...

PAC – MAN
TROUBLE SHOOTING
 PC A082-91375-A000
NOTE: All I.C. trouble shooting information is with the I.C. removed from circuit.
POSITIONCHIPPOSSIBLE TROUBLE
1-E74LS161All Characters are at top of screen - Characters move
horizontally only.
1-F74LS283Lines and Squares entire screen - Effects Self Test.
1-H74LS283Horizontal lines across screen in color.
1-K74LS283No Sounds - Game plays normal.
1-L74LS174Same as 1-K
1-M5623 (Prom)Same as 1 –K
1-NCD 4066Same as 1 –K
2-A93415 (Ram)Effects Color of all...

POSITIONCHIPPOSSIBLE TROUBLE
3-A74LS158No Characters in maze.
3-B74LS157No Video (Dead)
3-D74LS75Characters missing in maze - Game plays without
seeing Characters.
3-E74LS20No Video (Dead)
3-F74LS89Same as 3-D
3-H74LS89All Characters move jerking - Characters do not stay
in maze.
3-K74LS158No Sounds - Game Plays.
3-L74LS157No Sounds - Game Plays.
3-M1M5623No Sounds - Game Plays.
3-N74LS74Effects Sync - Color Diagonal Lines.
3-P74LS10No Video (Dead)
3-R74LS161No Video (Dead)
3-S74LS161Effects Sync -...

POSITIONCHIPPOSSIBLE TROUBLE
4-R2114 (Ram)Screen is blank with a Number One flashing – A single
Character can be seen.
5-A74LS157Blue Screen - All Characters are Squares – No Letters
or Numbers.
5-B74LS194Color Squares around each Character - All maze dots
are blue.
5-C74LS194Effects Maze - Characters have Squares around
them - Self Test in Red.
5-E9332 (Prom)Blue screen with Horizontal Squares - No Maze – No
Letters or Numbers random Characters.
5-F9332 (Prom)Effects Characters in Maze which are Squares...

POSITIONCHIPPOSSIBLE TROUBLE
8-A74LS107No Video (Dead)
8-B74LS368Same as 8-A
8-C74LS74Effects Sync - Diagonal Lines flashing.
8-D74LS367Effects Dip Switch settings.
8-E74LS367No Coin - No Up & Down Controls - 1st Player.
8-F74LS367No Controls - 2nd Player.
8-H74LS367No Test Switch - 1 & 2 Player Select.
8-K74LS259Stays in Self Test-Shows Memory OK.
9-C74LS161Screen covered with Garbage in Color.
10-A LM377 - LM1877No Sounds.
ADDITIONAL DEVICES
10-ADip SwitchEffects Coin Play - Number of Pat-Man Bonus...