Traduciendo paso 6
Verify Optional Memory Module Connectors are clean, not damaged and connected properly.
Remove the Optional Memory Module connector to inspect and assure the Memory Module connectors are clean and not damaged. See pg 83, or as noted in the PDF reader as pg 89, of the "thinkpad t40 t40p t41 t41p t42 t42p Maintenance Manual" for more details if needed. This manual is found in the Attached Documents section at the end of this Guide.
Insert and reconnect the Optional Memory Module making sure the connection is properly seated.