This document contains instructions for removing and installing the memory on your ThinkPad T20, T21, T22, T23 computer.

NOTE:: For ThinkPad T23 systems, use only a PC133 DIMM in your computer. If you install a DIMM that is not supported by your computer, the following error message may appear when the system starts: Error: Memory type mixing detected.

Attention: Before you start installing a module, touch a metal table or a grounded metal object. This action reduces any static electricity from your body. The static electricity could damage the DIMM.

Removing the memory

1. Turn off the computer; then disconnect the ac adapter and all cables from the computer.
2. Close the computer display, and turn it over.
3. Remove the battery.
4. Loosen the screw on the memory slot cover; then remove the cover as indicated by 1. Do not remove screw.
5. Remove the cover as indicated by 2.
   
6. Press out on the latches on both edges of the socket the same time as indicated by 3.
7. Remove the DIMM as indicated by 4.
8. Replace the memory slot cover; then tighten the screw.
   

Installing memory

1. Perform steps 2 through 5 in reverse order.
2. Replace the memory slot cover; then tighten the screw