Difference between revisions of "Baby Pac-Man"

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{{WIP}}
 
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Click to go back to the [[Bally/Stern|1977-1985 Bally/Stern]] repair guide.<br><br>
 
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==Introduction==
 
==Introduction==
−
Baby Pacman (Also: Baby Pacman) was produced in 1982 by Bally. Baby Pacman is one of the few hybrid video/pinball games that were ever produced, and only one of two hybrid games produced by Bally.  
+
[http://www.ipdb.org/machine.cgi?id=125 Baby Pac-Man] (Also written as: Baby Pacman) was produced in 1982 by Bally. Baby Pacman is one of the few hybrid video/pinball games that were ever produced, and only the first of two hybrid games produced by Bally.
−
 
 
−
==Technical Info==
 
  
 
===System Overview===
 
===System Overview===
Line 18: Line 13:
 
====Production Game====
 
====Production Game====
 
(TODO: photos of the game)
 
(TODO: photos of the game)
 +
 +
====Game Features & Rules====
 +
Game features & rules are documented on [https://pacman.fandom.com/wiki/Baby_Pac-Man_(game)#Pinball_mode the Pac-Man wiki site]
  
 
===Boards===
 
===Boards===
Line 35: Line 33:
  
 
====Vidiot====
 
====Vidiot====
−
This game uses a Bally AS-2518-121 Video board to display output on the monitor, output sound, and receive input from the control board's joystick and buttons. Because this board is reasonably complex and unique, it can be a central point of failure in this game. A modified version of this board named the "Vidiot Deluxe" board was used in Bally's second hybrid game, [http://www.ipdb.org/machine.cgi?id=1083 Granny and the Gators]. The two boards are different enough to not be cross-compatible.
+
This game uses a Bally AS-2518-121 Video board to display output on the monitor, output sound, and receive input from the control board's joystick and buttons. Because this board is reasonably complex and unique, it can be a central point of failure in this game. A modified version of this board named the "Vidiot Deluxe" board was used in Bally's second hybrid game, [[Granny and the Gators]]. The two boards are different enough to not be cross-compatible.
  
 
Four 2764 eproms are used for the video section of the vidiot board at U9-U12. The sound section of the board uses one 2764 eprom at U29.
 
Four 2764 eproms are used for the video section of the vidiot board at U9-U12. The sound section of the board uses one 2764 eprom at U29.
Line 84: Line 82:
 
==Problems and Fixes==
 
==Problems and Fixes==
  
−
====Artwork====
+
===Artwork===
 
All the artwork found on the game is being reproduced by [http://www.phoenixarcade.com/art.htm#babypacman The Phoenix Arcade]--The sideart, playfield overlay, plastics, bezel backglass, and marquee.
 
All the artwork found on the game is being reproduced by [http://www.phoenixarcade.com/art.htm#babypacman The Phoenix Arcade]--The sideart, playfield overlay, plastics, bezel backglass, and marquee.
  
Line 216: Line 214:
 
| 0.156"
 
| 0.156"
 
|}
 
|}
 +
 +
===MPU===
 +
====Game Will not Successfully Boot Up====
 +
[[File:Baby Pac Fuses.jpg|thumb|200px|left|Fuse block as seen under the playfield of Baby Pac-Man]]<br>
 +
If the MPU will not boot, but everything else seems to check out, inspect the middle fuse located underneath the playfield.  The fuse block is located just above the right flipper of the playfield.  The middle fuse is a 10A fast blo fuse.  This particular line is the OA phase of the switched illumination bus.  The OA phase of the switched illumination is used for the zero crossing circuit on the MPU board.  Instead of using the 48v solenoid bus, the -133 MPU uses the OA phase instead.
 +
<br clear=all>
  
 
===Vidiot Board===
 
===Vidiot Board===
Line 265: Line 269:
 
If the solenoids never fire, check the fuses found on the underside of the playfield.
 
If the solenoids never fire, check the fuses found on the underside of the playfield.
  
 +
=====Solenoid Chart=====
 +
{| class="wikitable sortable"
 +
! Sol. No !! Solenoid description !! Solenoid Type !! Wire Code !! Wire Color !! Connector !! Driver Transistor !! Solenoid Coil Type
 +
|-
 +
| 1 || Outhole || Momentary || 74 || Orn-Grn || A3J6-3 || Q37 || AO-27-1300
 +
|-
 +
| 2 || Drop Target Reset || Momentary || 78 || Orn-Blk || A3J6-4 || Q36 || NO-26-1900
 +
|-
 +
| 3 || Drop Target #1 (Left) || Momentary || 71 || Orn-Red || A3J6-7 || Q35 || CJ-31-2000
 +
|-
 +
| 4 || Drop Target #2 || Momentary || 91 || Gry-Red || A3J6-8 || Q34 || CJ-31-2000
 +
|-
 +
| 5 || Drop Target #3 || Momentary || 81 || Blk-Red || A3J6-11 || Q33 || CJ-31-2000
 +
|-
 +
| 6 || Drop Target #4 || Momentary || 85 || Blk-Wht || A3J6-12 || Q32 || CJ-31-2000
 +
|-
 +
| 7 || Drop Target #5 (Right) || Momentary || 83 || Blk-Yel || A3J5-4 || Q31 || CJ-31-2000
 +
|-
 +
| 8 || Flipper enabling relay || Continuous || -- || -- || -- || Q40 || 48V Relay
 +
|-
 +
| 9 || Left Maze Saucer || Continuous || 67 || Brn-Orn || A3J6-2 || Q39 || AO-27-1300
 +
|-
 +
| 10 || Right Maze Saucer || Continuous || 18 || Red-Blk || A3J6-1 || Q38 || AO-27-1300
 +
|}
 +
 +
{| class="wikitable sortable"
 +
! Flipper Circuits !! Power Wire !! Flipper Coil Wire !! Flipper Connector !! Flipper Button Wire !! Button Connector !! Coil
 +
|-
 +
| Left Flipper || 60 (Brn) || 40 (Grn) || A3J10-5 || 20 (Blu) || A3J11-3 || AQ-25-500/34-4500
 +
|-
 +
| Right Flipper || 60 (Brn) || 70 (Orn) || A3J10-4 || 10 (Red) || A3J11-5 || AQ-25-500/34-4500
 +
|}
  
 
(TODO: symptoms of a bad capacitor)
 
(TODO: symptoms of a bad capacitor)
Line 272: Line 308:
  
 
[[File:Baby-pacman-lamp-scr-diagram.gif|400px|thumb|left|Diagram for showing which feature lamps correspond to each SCR]]<br clear="all">
 
[[File:Baby-pacman-lamp-scr-diagram.gif|400px|thumb|left|Diagram for showing which feature lamps correspond to each SCR]]<br clear="all">
 +
 +
=====Lamp Chart=====
 +
{| class="wikitable sortable"
 +
! SCR !! conn. !! lamp description !! code !! wire color !! phase !! tr type
 +
|-
 +
| Q17 || A3J2-5 || Arrow 2K || 95 || Gry-Wht || A || 2N5060
 +
|-
 +
| Q09 || A3J2-11 || Arrow 4K || 35 || Yel-Wht || A || 2N5060
 +
|-
 +
| Q17 || A3J2-5 || Arrow 6K || 95 || Gry-Wht || B || 2N5060
 +
|-
 +
| Q09 || A3J2-11 || Arrow 8K || 35 || Yel-Wht || B || 2N5060
 +
|-
 +
| Q16 || A3J3-15 || Energizer #1 || 98 || Gry-Blk || A || 2N5060
 +
|-
 +
| Q24 || A3J3-9 || Energizer #2 || 30 || Yel || A || 2N5060
 +
|-
 +
| Q25 || A3J3-8 || Energizer #3 || 78 || Orn-Blk || B || 2N5060
 +
|-
 +
| Q30 || A3J3-2 || Energizer #4 || 72 || Orn-Blu || A || 2N5060
 +
|-
 +
| Q28 || A3J2-4 || Extra Ball Arrow || 85 || Blk-Wht || A || 2N5060
 +
|-
 +
| Q12 || A3J1-6 || Fruit Outlane || 84 || Blk-Grn || A || 2N5060
 +
|-
 +
| Q22 || A3J3-11 || Fruits "F" || 43 || Grn-Yel || A || 2N5060
 +
|-
 +
| Q01 || A3J1-15 || Fruits "R" || 10 || Red || A || 2N5060
 +
|-
 +
| Q22 || A3J3-11 || Fruits "U" || 43 || Grn-Yel || B || 2N5060
 +
|-
 +
| Q01 || A3J1-15 || Fruits "I" || 10 || Red || B || 2N5060
 +
|-
 +
| Q19 || A3J3-13 || Fruits "T" || 36 || Yel-Brn || A || 2N5060
 +
|-
 +
| Q03 || A3J1-13 || Fruits "S" || 21 || Blu-Red || A || 2N5060
 +
|-
 +
| Q03 || A3J1-13 || Inside Lane Left || 21 || Blu-Red || B || 2N5060
 +
|-
 +
| Q19 || A3J3-13 || Inside Lane Right || 36 || Yel-Brn || B || 2N5060
 +
|-
 +
| Q08 || A3J2-12 || Outhole Left Side Flasher || 91 || Gry-Red || A || 2N5060
 +
|-
 +
| Q28 || A3J2-4 || Outhole Right Side Flasher || 85 || Blk-Wht || B || 2N5060
 +
|-
 +
| Q27 || A3J3-6 || Row #1 "P" || 25 || Blu-Wht || B || 2N5060
 +
|-
 +
| Q05 || A3J1-11 || Row #1 "A" (First) || 15 || Red-Wht || B || 2N5060
 +
|-
 +
| Q27 || A3J3-6 || Row #1 "C" || 25 || Blu-Wht || A || 2N5060
 +
|-
 +
| Q05 || A3J1-11 || Row #1 "M" || 15 || Red-Wht || A || 2N5060
 +
|-
 +
| Q16 || A3J3-15 || Row #1 "A" (Second) || 98 || Gry-Blk || B || 2N5060
 +
|-
 +
| Q06 || A3J1-10 || Row #1 "N" || 81 || Blk-Red || B || 2N5060
 +
|-
 +
| Q20 || A3J3-12 || Row #2 "P" || 40 || Grn || A || 2N5060
 +
|-
 +
| Q07 || A3J1-9 || Row #2 "A" (First) || 14 || Red-Grn || A || 2N5060
 +
|-
 +
| Q20 || A3J3-12 || Row #2 "C" || 40 || Grn || B || 2N5060
 +
|-
 +
| Q07 || A3J1-9 || Row #2 "M" || 14 || Red-Grn || B || 2N5060
 +
|-
 +
| Q24 || A3J3-9 || Row #2 "A" (Second) || 30 || Yel || B || 2N5060
 +
|-
 +
| Q13 || A3J1-5 || Row #2 "N" || 95 || Gry-Wht || B || 2N5060
 +
|-
 +
| Q29 || A3J3-3 || Row #3 "P" || 64 || Brn-Grn || B || 2N5060
 +
|-
 +
| Q11 || A3J1-7 || Row #3 "A" (First) || 91 || Gry-Red || B || 2N5060
 +
|-
 +
| Q29 || A3J3-3 || Row #3 "C" || 64 || Brn-Grn || A || 2N5060
 +
|-
 +
| Q11 || A3J1-7 || Row #3 "M" || 91 || Gry-Red || A || 2N5060
 +
|-
 +
| Q25 || A3J3-8 || Row #3 "A" (Second) || 78 || Orn-Blk || A || 2N5060
 +
|-
 +
| Q14 || A3J1-4 || Row #3 "N" || 56 || Wht-Brn || B || 2N5060
 +
|-
 +
| Q26 || A3J3-7 || Row #4 "P" || 23 || Blu-Yel || B || 2N5060
 +
|-
 +
| Q18 || A3J1-3 || Row #4 "A" (First) || 35 || Yel-Wht || B || 2N5060
 +
|-
 +
| Q26 || A3J3-7 || Row #4 "C" || 23 || Blu-Yel || A || 2N5060
 +
|-
 +
| Q18 || A3J1-3 || Row #4 "M" || 35 || Yel-Wht || A || 2N5060
 +
|-
 +
| Q30 || A3J3-2 || Row #4 "A" (Second) || 72 || Orn-Blu || B || 2N5060
 +
|-
 +
| Q12 || A3J1-6 || Row #4 "N" || 84 || Blk-Grn || B || 2N5060
 +
|-
 +
| Q06 || A3J1-10 || Saucer Arrow Left || 81 || Blk-Red || A || 2N5060
 +
|-
 +
| Q13 || A3J1-5 || Saucer Arrow Right || 95 || Gry-Wht || A || 2N5060
 +
|-
 +
| Q14 || A3J1-4 || Shoot Again || 56 || Wht-Brn || A || 2N5060
 +
|-
 +
| Q04 || A3J1-12 || Spinner Arrow Left || 20 || Blu || A || 2N5060
 +
|-
 +
| Q23 || A3J3-10 || Spinner Arrow Right || 13 || Red-Yel || B || 2N5060
 +
|-
 +
| Q15 || A3J3-14 || Tunnel "T" || 67 || Brn-Orn || A || 2N5060
 +
|-
 +
| Q02 || A3J1-14 || Tunnel "U" || 53 || Wht-Yel || A || 2N5060
 +
|-
 +
| Q15 || A3J3-14 || Tunnel "N" (First) || 67 || Brn-Orn || B || 2N5060
 +
|-
 +
| Q02 || A3J1-14 || Tunnel "N" (Second) || 53 || Wht-Yel || B || 2N5060
 +
|-
 +
| Q23 || A3J3-10 || Tunnel "E" || 13 || Red-Yel || A || 2N5060
 +
|-
 +
| Q04 || A3J1-12 || Tunnel "L" || 20 || Blu || B || 2N5060
 +
|-
 +
| Q08 || A3J2-12 || Tunnel Outlane || 91 || Gry-Red || B || 2N5060
 +
|-
 +
| Q10 || A3J2-10 ||  ||  ||  || A || 2N5060
 +
|-
 +
| Q10 || A3J2-10 ||  ||  ||  || B || 2N5060
 +
|-
 +
| Q21 || A3J2-3 ||  ||  ||  || A || 2N5060
 +
|-
 +
| Q21 || A3J2-3 ||  ||  ||  || B || 2N5060
 +
|}
  
 
=====Individual Feature Lamp Dim, Flickering, or Stuck On=====
 
=====Individual Feature Lamp Dim, Flickering, or Stuck On=====
Line 289: Line 450:
 
Feature lamps that are stuck in the "always on" state typically are "stuck" on in pairs, since each SCR on the driver board drives two lamps. So, when an SCR fails, it typically affects two lamps. If a pair of lamps are stuck on, use the diagram above to find out which SCR on the board the lamps correspond to, and replace that SCR. The SCRs were originally 2N5060, but can be replaced with 2N5064, which are rated for a higher voltage.
 
Feature lamps that are stuck in the "always on" state typically are "stuck" on in pairs, since each SCR on the driver board drives two lamps. So, when an SCR fails, it typically affects two lamps. If a pair of lamps are stuck on, use the diagram above to find out which SCR on the board the lamps correspond to, and replace that SCR. The SCRs were originally 2N5060, but can be replaced with 2N5064, which are rated for a higher voltage.
  
 +
=====SCR Upgrade=====
 +
Since 2N5060 and 2N5064 SCR's drive two lamps, but were not designed with the intention of driving two lamps, these components tend to blow fairly easily on the driver board. As an upgrade, bad SCR's can be replaced with MCR106's (which are designed to drive two lamps) as indicated in a [https://forums.arcade-museum.com/showthread.php?t=232992 discussion thread on the KLOV forums].
 +
 +
The legs on a MCR106 are arranged differently than on a 2N5060/2N5064. The following diagram has the MCR106 legs labeled, so use it to insert the legs that correspond to the labels for the through-holes on the driver board for each SCR.
  
−
(TODO: How to test SCRs with a multimeter)
+
[[file:Mcr106-leg-labels.jpg|thumb|left|250px|MCR106 leg labels]]<br clear=all>
  
 
===Monitor===
 
===Monitor===
Line 358: Line 523:
 
===Lower Playfield Plastics Lighting===
 
===Lower Playfield Plastics Lighting===
  
 +
==Switch Matrix Chart==
 +
 +
{| class="wikitable"
 +
!  !!  !!  !! Strobe 0 !! Strobe 1 !! Strobe 2 !! Strobe 3 !! Strobe 4
 +
|-
 +
!
 +
| to Playfield || -- || A4J2-1 Wht-Red (51) || A4J2-2 Orn (70) || A4J2-3 Gry-Yel (93) || A4J2-4 Wht-Yel (53) || A4J2-5 Yel-Red (31)
 +
|-
 +
!
 +
| -- || to Cabinet || A4J3-2 Wht-Red (51) || A4J3-3 Orn (70) ||  ||  ||
 +
|-
 +
! Return I-0
 +
| A4J2-8 Wht-Grn (54) || A4J3-9 Wht-Grn (54) || 1 Right Flipper End of Stroke || 9 Coin Chute III (Right) || 17 Top Loop Lane (Right) || 25 Drop Target #5 (Right) || 33 Not Used
 +
|-
 +
! Return I-1
 +
| A4J2-9 Brn-Yel (63) || A4J3-10 Brn-Yel (63) || 2 Not Used || 10 Coin Chute I (Left) || 18 Not Used || 26 Drop Target #4 || 34 Not Used
 +
|-
 +
! Return I-2
 +
| A4J2-10 Wht-Orn (57) || A4J3-11 Wht-Orn (57) || 3 Start Game for 2 Players || 11 Not Used || 19 Not Used || 27 Drop Target #3 || 35 Not Used
 +
|-
 +
! Return I-3
 +
| A4J2-11 Orn-Blk (78) || A4J3-12 Orn-Blk (78) || 4 Not Used || 12 Not Used || 20 Top Loop Lane (Left) || 28 Drop Target #2 || 36 Not Used
 +
|-
 +
! Return I-4
 +
| A4J2-12 Brn (60) || A4J3-13 (not used) || 5 Rebounds (2) || 13 Not Used || 21 Tunnel Outlane || 29 Drop Target #1 (Left) || 37 Not Used
 +
|-
 +
! Return I-5
 +
| A4J2-13 Wht-Brn (56) || A4J3-14 Wht-Brn (56) || 6 Start Game for 1 Player || 14 Not Used || 22 Fruits Outlane || 30 Outhole Saucer || 38 Not Used
 +
|-
 +
! Return I-6
 +
| A4J2-14 Brn-Wht (65) || A4J3-15 Brn-Wht (65) || 7 Right Spinner || 15 Tilt (3) || 23 Right Inside Outlane || 31 Right Maze Saucer || 39 Not Used
 +
|-
 +
! Return I-7
 +
| A4J2-15 Wht-Blu (52) || A4J3-16 Wht-Blu (52) || 8 Left Spinner || 16 Slam (2) || 24 Left Inside Outlane || 32 Left Maze Saucer || 40 Not Used
 +
|}
  
 
==Rubber Rings==
 
==Rubber Rings==
−
Rubber Ring Sizes goes here
+
* (2) 3/4"
 +
* (2) 1-1/2"
 +
* (4) 2-1/2"
 +
* (2) Flipper rubbers
 +
* (2) 5/16"
 +
* (4) Post rubbers
  
 
==Photos==
 
==Photos==
Line 370: Line 575:
  
 
==References==
 
==References==
 +
 +
 +
Return to [[Bally/Stern]] page.

Latest revision as of 11:56, 10 November 2024

1 Introduction

Baby Pac-Man (Also written as: Baby Pacman) was produced in 1982 by Bally. Baby Pacman is one of the few hybrid video/pinball games that were ever produced, and only the first of two hybrid games produced by Bally.

1.1 System Overview

1.1.1 Prototype

There were 4 or 5 half-height prototype games made. One of them is in Todd Tuckey's personal collection (owner of TNT Amusements). Baby Pacman gets its name from these prototypes since they were originally intented to be a "baby-sized" arcade game, when compared to full-sized arcade games.

Todd Tuckey's Baby Pacman prototype


1.1.2 Production Game

(TODO: photos of the game)

1.1.3 Game Features & Rules

Game features & rules are documented on the Pac-Man wiki site

1.2 Boards

1.2.1 MPU

This game uses a Bally AS-2518-133 MPU. This is nearly identical to the AS-2518-35 board, with a few minor differences. A -35 board can be converted to a -133 board and vice-versa by swapping a few through-hole components. See the notes on this conversion process on the main Bally/Stern page.

This game uses two ROMs. A 2732 eprom at U6 and a 2532 eprom at U2. The MPU board can be re-jumpered to accept two 2732 eproms.

The diagnostic LED flash sequence is slightly different on the -133 board than the -35 board. The -133 board's diagnostic LED displays 6 flashes, while the -35 board displays 7 flashes. (TODO: Include reason for this difference) Otherwise, troubleshooting procedures are identical to that of the -35 board.

1.2.2 Driver/Lamp

This game uses a Bally AS-2518-107 combo board to drive both the feature lamps and the solenoids. This board is also found in Bally's second hybrid game, Granny and the Gators.

Each SCR in the lower left area of the board (marked as Q1 through Q28) is responsible for driving two lamps. If one of the SCR's fails, usually a pair of lamps won't respond and will either be stuck either on or off.

If the MPU is not working or not communicating with the vidiot board, the driver board will still turn blink the feature lamps on and off haphazardly, but they will not be sequenced. When the MPU is working properly, the lamps will turn on and off according to a specific sequence.

1.2.3 Vidiot

This game uses a Bally AS-2518-121 Video board to display output on the monitor, output sound, and receive input from the control board's joystick and buttons. Because this board is reasonably complex and unique, it can be a central point of failure in this game. A modified version of this board named the "Vidiot Deluxe" board was used in Bally's second hybrid game, Granny and the Gators. The two boards are different enough to not be cross-compatible.

Four 2764 eproms are used for the video section of the vidiot board at U9-U12. The sound section of the board uses one 2764 eprom at U29.

The vidiot board can be tested for sound and video without needing the MPU.

1.2.4 Rectifier

This game uses a Bally AS-2518-132 rectifier board, which is nearly identical to the standard AS-2518-54 rectifier board.

Since this game does not use any score displays (like normally found on a pinball machine), the +230VDC (190VDC unregulated) found at TP2 is not used. This means that it is not necessary to install a fuse at F2.

The -132 board is very similar to an AS-2518-54 rectifier board, but with a few modifications/improvements. The -132 board uses 6 amp diodes at CR5, CR6, CR7, and CR8, while the -54 board uses 3 amp diodes. The 6 amp diodes provide better heat dissipation. The -132 board uses two circuits for the general illumination, and thus also uses two separate fuses (found at F5 and F6). This allows for more lamps by spreading the load between two circuits. The early revision of -54 board only uses one circuit and one fuse, however, AS-2518-54 revision B includes two circuits and two fuses for the general illumination.

The Fuse values differ between the -132 and -54 boards.

1.3 Monitor

This game originally came with a 13" Wells Gardner 13K4800 video game monitor mounted vertically.

(TODO: include more details about the monitor and possible replacement options)

1.4 Speakers

This game uses two oval 3" x 5" 4 Watt 4 ohm speakers in mono, which are mounted above the coin door on the inside of the cabinet. If necessary, a single 4 Watt 8 ohm speaker can be used (Note: Do *not* use two 8 ohm speakers!)

1.5 Playfield

Baby Pacman has two distinct types of playfields. An earlier version of the playfield uses a matrix of lamp sockets for the feature lamps. A later version of the playfield uses a circuit board with twist-on sockets. The version with the lamp sockets was considered to be difficult to work on and prone to shorting out bulbs in the sockets or SCRs on the driver board.

Playfield with lamp sockets
Playfield with lamp board


The two different playfields appear to use different connectors, so it may not match up with the connector found in the cabinet. A pigtail adapter might be needed to adapt the playflield connector to the cabinet connector if one type of playfield is being swapped in for another.


1.6 Fluorescent Lamp

This game uses a fluorescent lamp behind the marquee, which is connected directly to the transformer.

(TODO: Include what type and size of lamp)


1.7 Bezel

There are two versions of the Baby Pacman bezel.

One version has no instructions or scoring information on the bezel. As an after-thought, Bally produced stickers which could be added to the bezel that included "escape to pin" instructions along the bottom edge of the bezel and scoring information in the lower right. These stickers had rounded corners and white backgrounds.

The second version of the bezel has instructions and scoring information included within the artwork. This is the more common version by far.

Bezel with scoring information within the artwork



2 Problems and Fixes

2.1 Artwork

All the artwork found on the game is being reproduced by The Phoenix Arcade--The sideart, playfield overlay, plastics, bezel backglass, and marquee.

2.2 Connectors

IDC Connectors
0.100" Molex Connector

The IDC connectors in this machine are a weak link. They were a cost-cutting measure when these machines were originally built, and as a result, often fail and need to be re-pinned because either the wire pops out of the pin in the connector, or the connector pin gets too loose and can't make contact with the header pins. This can be a source of many problems. It can sometimes appear as a consistent discontinuity issue, an intermittent issue as the machine moves/vibrates, or as heat causes things to expand and possibly loose contact. It is a good idea to replace any problematic IDC connectors with molex KK-series connectors. Some individuals recommend only replacing the connectors with problems to save some time, while others recommend just replacing them all at once in order to avoid potential future issues with the IDC connectors.


The connectors can be purchased from Great Plains Electronics and Big Daddy Enterprises. The 0.100" 25-pin and 28-pin connectors have been discontinued, so they may be difficult to obtain. If necessary, two smaller connectors can be used side-by-side in place of the larger 25 or 28-pin connectors.

When re-pinning the connectors, note that there are a few pins that have two wires connected to a single pin on the MPU board's J2 connector and the Vidiot board's J8 connector. The wiring for all the connector pins can be found on page 38 in the manual on the diagram labeled "Wiring Diagram Video-Pin Cabinet".

Baby Pacman uses both 0.100" header pins and 0.156" header pins. Here is a list of all the IDC connectors found on the circuit boards:

Board Connector Pins Pin Size
MPU J1 28 0.100"
MPU J2 15 0.100"
MPU J3 16 0.100"
MPU J4 19 0.100"
Driver J1 15 0.100"
Driver J2 12 0.100"
Driver J3 15 0.100"
Driver J4 10 0.156"
Driver J5 6 0.156"
Driver J6 12 0.156"
Driver J7 6 0.156"
Driver J8 25 0.100"
Driver J9 10 0.100"
Driver J10 6 0.156"
Driver J11 6 0.156"
Vidiot J1 28 0.100"
Vidiot J2 20 0.100"
Vidiot J3 12 0.156"
Vidiot J4 12 0.156"
Vidiot J5 2 0.156"
CRT Board ? 6 0.156"
CRT Board ? 2 0.156"

2.3 MPU

2.3.1 Game Will not Successfully Boot Up

Fuse block as seen under the playfield of Baby Pac-Man


If the MPU will not boot, but everything else seems to check out, inspect the middle fuse located underneath the playfield. The fuse block is located just above the right flipper of the playfield. The middle fuse is a 10A fast blo fuse. This particular line is the OA phase of the switched illumination bus. The OA phase of the switched illumination is used for the zero crossing circuit on the MPU board. Instead of using the 48v solenoid bus, the -133 MPU uses the OA phase instead.

2.4 Vidiot Board

2.4.1 Video

2.4.1.1 Color Bars

If the monitor displays color bars, that usually means (most of) the vidiot board is operational.

Color bar test


2.4.1.2 Communications Test Problems

If everything is working correctly, the communications test found in the diagnostics menu will display two columns of identical numbers.

Communications test with no problems


2.4.1.2.1 Missing Number Columns

If one or both columns are missing, one or more of your connectors is not plugged in, or the connectors/pins might be dirty. Check J1 on the vidiot board. Check J1 and J2 on the MPU.

2.4.1.2.2 Missmatching Number Columns

If numbers between the receive (RCV) and transmit (XMIT RCV) columns are mismatching, that usually indicates a connectivity issues with wires, pins, or connectors.

Mismatch in the receive and transmit columns


To perform connectivity tests, the following chart may be helpful. Each column in the communications test should match the numbers under the "signal" column in the chart. If not, find the corresponding row and column on the chart, and perform continuity tests between the resistor of one side and the resistor of the other. Testing on the resistor leads ensures that pin connectivity is tested.

Connectivity chart for MPU-to-vidiot communication


If connector and header pin issues are ruled out, there may be broken traces along the line as indicated by the incorrect column numbers. It may be helpful to hold the circuit board up to a light. Additionally, chip sockets may need to be removed in order to see if there was any damage done to the board before the socket was installed.

A circuit board held up to a light with a broken trace circled in yellow


If broken traces are ruled out, the legs of a socketed chip might be tarnished. Use a pink rubber eraser to gently clean them off.

Next, replace any suspected sockets.

After that, replace any suspected chips.

2.4.1.2.3 0F Displayed in Columns

If "0F" is displayed down a receive or transmit column, that may indicate a short on one of the boards. Do connectivity tests between neighboring pins on each board to see if any of them are making contact. Keep in mind that there are a few pins that have multiple wires connected to them.

0F diplayed in a communications test


2.4.2 Sound

(TODO: Add common sound issues)

2.5 Driver Board

2.5.1 Solenoids

If the solenoids never fire, check the fuses found on the underside of the playfield.

2.5.1.1 Solenoid Chart
Sol. No Solenoid description Solenoid Type Wire Code Wire Color Connector Driver Transistor Solenoid Coil Type
1 Outhole Momentary 74 Orn-Grn A3J6-3 Q37 AO-27-1300
2 Drop Target Reset Momentary 78 Orn-Blk A3J6-4 Q36 NO-26-1900
3 Drop Target #1 (Left) Momentary 71 Orn-Red A3J6-7 Q35 CJ-31-2000
4 Drop Target #2 Momentary 91 Gry-Red A3J6-8 Q34 CJ-31-2000
5 Drop Target #3 Momentary 81 Blk-Red A3J6-11 Q33 CJ-31-2000
6 Drop Target #4 Momentary 85 Blk-Wht A3J6-12 Q32 CJ-31-2000
7 Drop Target #5 (Right) Momentary 83 Blk-Yel A3J5-4 Q31 CJ-31-2000
8 Flipper enabling relay Continuous -- -- -- Q40 48V Relay
9 Left Maze Saucer Continuous 67 Brn-Orn A3J6-2 Q39 AO-27-1300
10 Right Maze Saucer Continuous 18 Red-Blk A3J6-1 Q38 AO-27-1300
Flipper Circuits Power Wire Flipper Coil Wire Flipper Connector Flipper Button Wire Button Connector Coil
Left Flipper 60 (Brn) 40 (Grn) A3J10-5 20 (Blu) A3J11-3 AQ-25-500/34-4500
Right Flipper 60 (Brn) 70 (Orn) A3J10-4 10 (Red) A3J11-5 AQ-25-500/34-4500

(TODO: symptoms of a bad capacitor)

2.5.2 Lamps

On the driver board, a bank of SCR's labeled with Q## are responsible for driving the feature lamps on the playfield. Each SCR drives two lamps. The driver board schematic shows which feature lamps correspond to each SCR, however, referring this diagram should save some time.

Diagram for showing which feature lamps correspond to each SCR


2.5.2.1 Lamp Chart
SCR conn. lamp description code wire color phase tr type
Q17 A3J2-5 Arrow 2K 95 Gry-Wht A 2N5060
Q09 A3J2-11 Arrow 4K 35 Yel-Wht A 2N5060
Q17 A3J2-5 Arrow 6K 95 Gry-Wht B 2N5060
Q09 A3J2-11 Arrow 8K 35 Yel-Wht B 2N5060
Q16 A3J3-15 Energizer #1 98 Gry-Blk A 2N5060
Q24 A3J3-9 Energizer #2 30 Yel A 2N5060
Q25 A3J3-8 Energizer #3 78 Orn-Blk B 2N5060
Q30 A3J3-2 Energizer #4 72 Orn-Blu A 2N5060
Q28 A3J2-4 Extra Ball Arrow 85 Blk-Wht A 2N5060
Q12 A3J1-6 Fruit Outlane 84 Blk-Grn A 2N5060
Q22 A3J3-11 Fruits "F" 43 Grn-Yel A 2N5060
Q01 A3J1-15 Fruits "R" 10 Red A 2N5060
Q22 A3J3-11 Fruits "U" 43 Grn-Yel B 2N5060
Q01 A3J1-15 Fruits "I" 10 Red B 2N5060
Q19 A3J3-13 Fruits "T" 36 Yel-Brn A 2N5060
Q03 A3J1-13 Fruits "S" 21 Blu-Red A 2N5060
Q03 A3J1-13 Inside Lane Left 21 Blu-Red B 2N5060
Q19 A3J3-13 Inside Lane Right 36 Yel-Brn B 2N5060
Q08 A3J2-12 Outhole Left Side Flasher 91 Gry-Red A 2N5060
Q28 A3J2-4 Outhole Right Side Flasher 85 Blk-Wht B 2N5060
Q27 A3J3-6 Row #1 "P" 25 Blu-Wht B 2N5060
Q05 A3J1-11 Row #1 "A" (First) 15 Red-Wht B 2N5060
Q27 A3J3-6 Row #1 "C" 25 Blu-Wht A 2N5060
Q05 A3J1-11 Row #1 "M" 15 Red-Wht A 2N5060
Q16 A3J3-15 Row #1 "A" (Second) 98 Gry-Blk B 2N5060
Q06 A3J1-10 Row #1 "N" 81 Blk-Red B 2N5060
Q20 A3J3-12 Row #2 "P" 40 Grn A 2N5060
Q07 A3J1-9 Row #2 "A" (First) 14 Red-Grn A 2N5060
Q20 A3J3-12 Row #2 "C" 40 Grn B 2N5060
Q07 A3J1-9 Row #2 "M" 14 Red-Grn B 2N5060
Q24 A3J3-9 Row #2 "A" (Second) 30 Yel B 2N5060
Q13 A3J1-5 Row #2 "N" 95 Gry-Wht B 2N5060
Q29 A3J3-3 Row #3 "P" 64 Brn-Grn B 2N5060
Q11 A3J1-7 Row #3 "A" (First) 91 Gry-Red B 2N5060
Q29 A3J3-3 Row #3 "C" 64 Brn-Grn A 2N5060
Q11 A3J1-7 Row #3 "M" 91 Gry-Red A 2N5060
Q25 A3J3-8 Row #3 "A" (Second) 78 Orn-Blk A 2N5060
Q14 A3J1-4 Row #3 "N" 56 Wht-Brn B 2N5060
Q26 A3J3-7 Row #4 "P" 23 Blu-Yel B 2N5060
Q18 A3J1-3 Row #4 "A" (First) 35 Yel-Wht B 2N5060
Q26 A3J3-7 Row #4 "C" 23 Blu-Yel A 2N5060
Q18 A3J1-3 Row #4 "M" 35 Yel-Wht A 2N5060
Q30 A3J3-2 Row #4 "A" (Second) 72 Orn-Blu B 2N5060
Q12 A3J1-6 Row #4 "N" 84 Blk-Grn B 2N5060
Q06 A3J1-10 Saucer Arrow Left 81 Blk-Red A 2N5060
Q13 A3J1-5 Saucer Arrow Right 95 Gry-Wht A 2N5060
Q14 A3J1-4 Shoot Again 56 Wht-Brn A 2N5060
Q04 A3J1-12 Spinner Arrow Left 20 Blu A 2N5060
Q23 A3J3-10 Spinner Arrow Right 13 Red-Yel B 2N5060
Q15 A3J3-14 Tunnel "T" 67 Brn-Orn A 2N5060
Q02 A3J1-14 Tunnel "U" 53 Wht-Yel A 2N5060
Q15 A3J3-14 Tunnel "N" (First) 67 Brn-Orn B 2N5060
Q02 A3J1-14 Tunnel "N" (Second) 53 Wht-Yel B 2N5060
Q23 A3J3-10 Tunnel "E" 13 Red-Yel A 2N5060
Q04 A3J1-12 Tunnel "L" 20 Blu B 2N5060
Q08 A3J2-12 Tunnel Outlane 91 Gry-Red B 2N5060
Q10 A3J2-10 A 2N5060
Q10 A3J2-10 B 2N5060
Q21 A3J2-3 A 2N5060
Q21 A3J2-3 B 2N5060
2.5.2.2 Individual Feature Lamp Dim, Flickering, or Stuck On

There are a few symptoms which indicate a failed/disconnected/missing diode on a feature lamp. One common symptom is being "stuck" on, but at about half the brightness of other lamps. Another symptom is dim flickering, even while the lamp is off. Lastly, when the lamp is active, the lamp may be at about half the brightness of the other lamps.

The lamp socket diode can be replaced with an 1N4004.

De-soldering is straight-forward, however, it might be a good idea to stuck a piece of paper or cardboard below the lamp receiving repairs so that solder doesn't drip down onto other components.

The banded side of the diode must connect to the small lug, while the un-banded side must connect to the large lug with the hole in it. Be mindful of which lug is which, as each lamp socket might be oriented in different directions from their neighboring lamp sockets.

Diode on a lamp socket


The best way to attach a new diode is to ensure a mechanical connection first by wrapping each end of the diode around each corresponding lamp lug. A fine pair of needle-nose pliers may be needed to help accomplish this. Then, solder and trim the excess leads as appropriate.

2.5.2.3 Feature Lamps Stuck On (In Pairs)

Feature lamps that are stuck in the "always on" state typically are "stuck" on in pairs, since each SCR on the driver board drives two lamps. So, when an SCR fails, it typically affects two lamps. If a pair of lamps are stuck on, use the diagram above to find out which SCR on the board the lamps correspond to, and replace that SCR. The SCRs were originally 2N5060, but can be replaced with 2N5064, which are rated for a higher voltage.

2.5.2.4 SCR Upgrade

Since 2N5060 and 2N5064 SCR's drive two lamps, but were not designed with the intention of driving two lamps, these components tend to blow fairly easily on the driver board. As an upgrade, bad SCR's can be replaced with MCR106's (which are designed to drive two lamps) as indicated in a discussion thread on the KLOV forums.

The legs on a MCR106 are arranged differently than on a 2N5060/2N5064. The following diagram has the MCR106 legs labeled, so use it to insert the legs that correspond to the labels for the through-holes on the driver board for each SCR.

MCR106 leg labels


2.6 Monitor

(TODO: How to adjust montor) (TODO: When to re-cap--symptoms)

2.7 Gameplay Issues

2.7.1 Game Displays "SLAM" on Monitor

On the coin door, a slam switch is mounted onto the lock. The slam switch on the coin door is normally open. If the slam switch is closed, the monitor displays the word "SLAM" in the center of the screen and the feature lamps on the playfield all go out. The general illumination will remain on.

The slam screen


2.7.2 Game Does Not Eject Ball on Button Press in Pinball Mode

The right flipper button is responsible for ejecting the ball during pinball mode. If the leaf switch is not working correctly or if the player does not press the button, the ball ejects automatically after a few seconds. If the player presses the right flipper button and nothing happens, that may indicate that there is something wired incorrectly or that the diode is missing on the right flipper switch. The right flipper is different from the left flipper since it is responsible for responding to the player to eject the ball in pinball mode.

The right flipper switch missing the diode
Right flipper switch wired correctly and with a diode


2.7.3 Game Randomly Exits Pinball Mode

There is a known issue where the game will appear to exit pinball mode at random (before the ball drains or lands in a saucer) and re-enters video game mode. That may indicate that the diode is reversed on the right flipper switch contacts. The right flipper is different from the left flipper since it is responsible for responding to the player to eject the ball in pinball mode.

The right flipper switch's diode is oriented in the wrong direction
The right flipper switch's diode is oriented correctly


Also see the Pinside discussion thread on this issue.

3 Documentation

3.1 Manual

The game manual and schematics are available on IPDB.

3.1.1 Cabinet Wiring Diagram Error

The cabinet wiring diagram has an error on the vidiot section; On VJ1, pin 3 appears twice. The second instance of pin 3 which connects to A4J1-20 is actually pin 14 on VJ1.

Cabinet wiring diagram error on V1



3.1.2 Playfield Schematic Labeling Error

A service bulletin noted a labeling error on the playfield schematic.

Playfield schematic error


3.2 Service Bulletins

3.2.1 EOS Switch Wiring Error

Description of issue
Diagram of EOS wiring


3.2.2 Vidiot & Monitor Adjustments

Description of issue


4 Modifications

4.1 LEDs

Unlike other classic Bally/Stern games from the same period, Baby Pacman does not typically require any modifications to be performed in order to be able to use LEDs as feature lamps.

4.2 Pigtail Playfield Adapter

When swapping playfields--especially a lamp socket playfield and lamp board playfield--The playfield connector might not match up with the connector in the cabinet. A pigtail adapter will allow the different playfields to be used without having to modify the original cabling or connectors.

Materials Needed:

  • (1) Connector Plug, 15-Pin, 0.084"
  • (1) Connector Receptacle, 24-Pin, 0.062"
  • (12) Crimp Contact, Socket, 0.062"
  • (12) Crimp Contact, Socket, 0.084"

(TODO: Wiring instructions)

4.3 Bezel Lighting

4.4 Lower Playfield Plastics Lighting

5 Switch Matrix Chart

Strobe 0 Strobe 1 Strobe 2 Strobe 3 Strobe 4
to Playfield -- A4J2-1 Wht-Red (51) A4J2-2 Orn (70) A4J2-3 Gry-Yel (93) A4J2-4 Wht-Yel (53) A4J2-5 Yel-Red (31)
-- to Cabinet A4J3-2 Wht-Red (51) A4J3-3 Orn (70)
Return I-0 A4J2-8 Wht-Grn (54) A4J3-9 Wht-Grn (54) 1 Right Flipper End of Stroke 9 Coin Chute III (Right) 17 Top Loop Lane (Right) 25 Drop Target #5 (Right) 33 Not Used
Return I-1 A4J2-9 Brn-Yel (63) A4J3-10 Brn-Yel (63) 2 Not Used 10 Coin Chute I (Left) 18 Not Used 26 Drop Target #4 34 Not Used
Return I-2 A4J2-10 Wht-Orn (57) A4J3-11 Wht-Orn (57) 3 Start Game for 2 Players 11 Not Used 19 Not Used 27 Drop Target #3 35 Not Used
Return I-3 A4J2-11 Orn-Blk (78) A4J3-12 Orn-Blk (78) 4 Not Used 12 Not Used 20 Top Loop Lane (Left) 28 Drop Target #2 36 Not Used
Return I-4 A4J2-12 Brn (60) A4J3-13 (not used) 5 Rebounds (2) 13 Not Used 21 Tunnel Outlane 29 Drop Target #1 (Left) 37 Not Used
Return I-5 A4J2-13 Wht-Brn (56) A4J3-14 Wht-Brn (56) 6 Start Game for 1 Player 14 Not Used 22 Fruits Outlane 30 Outhole Saucer 38 Not Used
Return I-6 A4J2-14 Brn-Wht (65) A4J3-15 Brn-Wht (65) 7 Right Spinner 15 Tilt (3) 23 Right Inside Outlane 31 Right Maze Saucer 39 Not Used
Return I-7 A4J2-15 Wht-Blu (52) A4J3-16 Wht-Blu (52) 8 Left Spinner 16 Slam (2) 24 Left Inside Outlane 32 Left Maze Saucer 40 Not Used

6 Rubber Rings

  • (2) 3/4"
  • (2) 1-1/2"
  • (4) 2-1/2"
  • (2) Flipper rubbers
  • (2) 5/16"
  • (4) Post rubbers

7 Photos

Teardown photos go here

8 Repair Logs

Did you do a repair? Log it here as a possible solution for others.


9 References

Return to Bally/Stern page.

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