IBM 1725 SLS - Manual (Page 225)

Hard Disks
8-41 Printer Options
4 Connect the power cable and ribbon cable from the assem-
bly kit to the new hard disk connectors.
» Note: The extra connector on the power cable is for future use and does
not connect to anything at this time.
5 With the controller board ribbon cable and the power cable
fitting under the brackets on the hard disk, attach the other
end of ribbon cable to the controller board connector and
the power cable to the 4-pin controller board connector.
The power cable is keyed so it fits only one way.
6 Line up the holes on the tray assembly with the holes on the
hard disk bracket flanges.
7 Insert the four Phillips screws you removed in step 2 into the
holes and tighten with a screwdriver.