IBM 704 - Manual (Page 213)

Adding Power Supplies
To add a power supply, do the following steps:
1. Locate the cover on the power-supply bay (at the back of the
power-supply chassis).
2. Remove the four screws from the cover.
3. Remove the power-supply cover and save for future use.
4. Support the power supply with the handle 3 on the back.
5. Slide the new or replacement power supply into the chassis.
6. Install the four screws ( 2 in the following figure) to secure the
power supply.
7. Connect the AC power cord to the back of the chassis. A
spring-loaded interlock at the AC receptacle 1 prevents the
power supply from being removed unless the power cord has
been removed.
8. Align the power-supply cover with the power-supply bay
opening.
9. Place the cover over the bay.
10. Reinstall the screws that you removed from the power-supply
cover.
Chapter 4. Installing Options 195