Dell Dimension XPS R Series Service Manual page 59

back of chassis
release buttons (2)
)LJXUH  &KDVVLV &RROLQJ )DQ $VVHPEO\ 5HPRYDO
 'LVFRQQHFW WKH FKDVVLV FRROLQJ IDQ FDEOH IURP WKH -0 FRQQHFWRU
RQ WKH V\VWHP ERDUG VHH )LJXUH  
 3UHVV WKH WZR UHOHDVH EXWWRQV RQ WKH EDFN RI WKH FKDVVLV DQG OLIW
WKH FKDVVLV FRROLQJ IDQ DVVHPEO\ RXW RI WKH FKDVVLV
Maintain upward pressure on the fan assembly while you press the two
release buttons.
chassis cooling
fan assembly
J8M1 connector
Removing and Replacing Parts 4-15