External Devices - Lenovo ThinkPad L420 User Manual

Hazardous voltage, current, and energy levels are present inside any component that has this label
attached. There are no serviceable parts inside these components. If you suspect a problem with
one of these parts, contact a service technician.

External devices

CAUTION:
Do not connect or disconnect any external device cables other than Universal Serial Bus (USB) and
1394 cables while the computer power is on; otherwise, you might damage your computer. To avoid
possible damage to attached devices, wait at least five seconds after the computer is shut down to
disconnect external devices.
Batteries
DANGER
Personal computers manufactured by Lenovo contain a coin cell battery to provide power to
the system clock. In addition, many mobile products, such as notebook computers, utilize a
rechargeable battery pack to provide system power when in portable mode. Batteries supplied by
Lenovo for use with your product have been tested for compatibility and should only be replaced
with approved parts.
Never attempt to open or service any battery. Do not crush, puncture, or incinerate batteries or
short circuit the metal contacts. Do not expose the battery to water or other liquids. Only recharge
the battery pack strictly according to instructions included in the product documentation.
Battery abuse or mishandling can cause the battery to overheat, which can cause gasses or flame
to "vent" from the battery pack or coin cell. If your battery is damaged, or if you notice any
discharge from your battery or the buildup of foreign materials on the battery leads, stop using the
battery and obtain a replacement from the battery manufacturer.
Batteries can degrade when they are left unused for long periods of time. For some rechargeable
batteries (particularly Lithium Ion batteries), leaving a battery unused in a discharged state could
increase the risk of a battery short circuit, which could shorten the life of the battery and can also
pose a safety hazard. Do not let rechargeable Lithium-Ion batteries completely discharge or store
these batteries in a discharged state.
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User Guide