HP ProBook 640 G1, 645 G1, 650 G1, and 655 G1 Notebook PCs - Maintenance and Service Guide

3. Disconnect the modem module cable (3) from the modem module.
4. Remove the modem module.
Reverse this procedure to install the modem module.
Primary memory module
The computer has one memory module compartment. The capacity of the computer can be upgraded by
adding a memory module to the vacant expansion memory module slot or by upgrading the existing memory
module in the primary memory module slot.
WARNING! To reduce the risk of electric shock and damage to the equipment, unplug the power cord
and remove all batteries before installing a memory module.
CAUTION: Electrostatic discharge (ESD) can damage electronic components. Before beginning any
procedure, ensure that you are discharged of static electricity by touching a grounded metal object.
CAUTION: To prevent information loss or an unresponsive system:
Shut down the computer before adding or replacing memory modules. Do not remove a memory module
while the computer is on, in the Sleep state, or in Hibernation.
If you are not sure whether the computer is off or in Hibernation, turn the computer on by pressing the power
button. Then shut down the computer through the operating system.
NOTE: To use a dual-channel configuration when adding a second memory module, be sure that both
memory modules are identical.
NOTE: The primary memory is located in the bottom memory slot and the expansion memory is located in
the top memory slot.
Description Spare part number
8-GB (PC3L, 12800, 1600) 693374-001
8-GB (PC3L, 12800, 1600) Samsung locked 835496-001
62 Chapter 5 Removal and replacement procedures for Customer Self-Repair parts