Epson Progression U12 - Manual (Page 115)

4. Locate one of the five power supply cables secured by the
clasps on the side of the subassembly. The cables are
labeled
P1
through P5; you can use any one of them.
Position the cable connector so its notched corners line up
with the notched comers of the power supply socket on
your drive, as shown below.
(This illustration shows a diskette drive. The power supply
connector is the same on a hard disk drive.)
5. Make sure the holes in the connector fit over all the pins in the
socket and then push in the connector.
Caution
If you do not align the connector correctly, you could
severely damage your drive when you push it in.
4-12 installing and Removing Drives