Epson MR Series Technical Reference Manual page 272

CAUTION:
Be careful not to drop the HDD when you remove it from the HDD bracket.
7. Pull out the 3.5"HDD from the HDD bracket while lifting up the 3.5"HDD in the direction of
the arrow. Then disconnect the HDD cable and remove the 3.5"HDD.
3.5"HDD
HDD cable
To install, reverse the removal procedure.
CAUTION:
Be careful not to injure yourself on the sharp edges of the metal parts of the IM-800.
9-56 Disassembly and Assembly Rev. I