| Pacman and Ms Pacman | 
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| PCB Modifications | |||
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your Pacman or Ms Pacman video game |
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| If your picture flips for player 2 in an upright cabinet, check for this modification: |
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| The method I would use for +5 volts modification: |
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| If your board does not have the above modification, and board still works on a +5 volt switching power supply, then the +5 volts is probably adjusted up way beyond +5 volts because of the voltage drop through the 2 diodes. (Or someone has put the jumper wire in a different location). Therefore, if you perform this modification, turn down the +5 volts as low as it will go before applying power to the board after modification is made. Not doing so may damage board because the circuit should never be operated above +5.25 volts. Once power has been re-applied, then adjust up to +5 volts, measured at the board (not the power supply). The will be a slight voltage drop through the wires. A good place to measure for the +5 volts is across C3, (470uf @ 16volts), which is located about 2 inches from the 2 larger side-by-side caps, (approximately where the yellow exclamation point is in the above diagram). Of course, if your board works without this mod, you may just want to leave as is, although I'd bet the +5 volts across C3 will be too low, which will result in unpredictable board operation. |
| Easy method of adding fast / slow with this modification: |
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