Lenovo MT 1871 Hardware Maintenance Manual page 77

Removing and replacing a FRU
Press the part indicated by the arrow 2 in the direction of
the arrow. This releases the latches of the keyboard from
the frame, so that the front side of the keyboard pops out.
2
4
3
When installing: Make sure that the connector 4 is
firmly attached.
73
ThinkPad R50/R50p and R51 Series