Apple PowerBook (3400 series) - Manual (Page 87)

Recharging the battery
To recharge the battery, plug in the power adapter. Macintosh PowerBook
3400 series batteries may be charged inside the computer. You may also use
an external battery charger designed specifically for Macintosh PowerBook
3400 series computers.
A lightning bolt icon appears in the battery monitor portion of the Control
Strip when the power adapter is plugged in and a battery is recharging.
The battery is recharged regardless of whether you are using the computer, or
the computer is off or in sleep; however, it will recharge more quickly if the
computer is off or in sleep.
WARNING Use only the external power adapter that came with your
computer. Adapters for other electronic devices (including other
portable computers) may look similar, but they may damage
your computer.
Power cord
Power adapter
Power adapter plug
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Power adapter port
87 Power Management