Baby Pac-Man

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3 Problems and Fixes

3.1 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 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"

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

The right flipper is responsible for ejecting the ball during pinball mode. If the button is not working correctly or if the player does not press it, 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 coil lugs. 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 coil missing the diode

Right flipper coil wired correctly and with a diode

3.5 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 coil lugs. 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 coil's diode is oriented in the wrong direction

The right flipper coil's diode is oriented correctly

Also see the Pinside discussion thread on this issue.

4 Paperwork

Manuals, schematics, coin cards...

5 Rubber Rings

Rubber Ring Sizes goes here

6 Photos

Teardown photos go here

8 Repair Logs

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