Ensuring Sufficient Power For Your Computer; Docking Power Considerations - Dell Latitude C640 User Manual

Connect the computer directly to an electrical outlet -
power strips, and the extension cable to verify that the computer turns on.
Eliminate possible interference -
other appliances.
Adjust the Power Properties -
Reseat the memory modules -
blank, reseat the memory

Ensuring Sufficient Power for Your Computer

Your computer's Intel® Pentium® 4 microprocessor requires more power than the microprocessors used in
some of Dell's previous portable computers. The computer achieves maximum performance with the 70-W
(standard) or 90-W (optional) AC adapter and the 4460-mAh battery (standard).
You can use the 3800-mAh and 3600-mAh batteries from earlier Dell computers, but these lower-capacity
batteries will discharge significantly faster. The computer is not designed to run with the Latitude 50-W AC
travel adapter.
NOTICE: Do not use a battery rated under 3600 mAh in this computer; lower-capacity batteries may
prevent the computer from powering up.

Docking Power Considerations

To achieve maximum performance when using the Dell C/Dock Expansion Station, you must use a 90-W AC
adapter with the expansion station. Using a 70-W AC adapter with the expansion station causes the
computer to run in reduced-performance mode and may result in an AC adapter warning message.
All Dell C/Dock Expansion Stations and C/Port Advanced Port Replicators manufactured after April 2002
shipped with 90-W AC adapters. If you have an earlier expansion station with a 70-W AC adapter and want
to upgrade for optimal performance, you can purchase a 90-W AC adapter from Dell.
The following table summarizes system performance expectations for the various AC adapters and docking
configurations.
Turn off nearby fans, fluorescent lights, halogen lamps, or
See "Power Management."
If the computer power light turns on but the display remains
modules.
Bypass power protection devices,