IBM 704 - Manual (Page 31)

Padlock Loops: The two side cover padlock loops enable you to
insert padlocks (not provided) to secure the side covers to the
system unit.
The electro-magnetic interference (EMI) door on the front of the
server also has a padlock loop. You can insert a small padlock
(not included) through this loop to secure the EMI door to the
system unit and help prevent unauthorized access to the hard
disk drives in the hot-swap bays.
Power Supplies: All PC Server 704 models support three
420-watt power supplies. In a three-supply system, the third
power supply provides redundant power.
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CAUTION:
Power supplies are easy to install and remove, but they
are not hot-swappable. Always disconnect all server
power cords and all power supply power cords before
you remove or install a power supply.
Power-Good Light and Current-Good Light: These green lights
provide status information about the power supply, as follows:
Power-Good Light (PS) Current-Good Light (I) Description
On On Power supply on and
OK
Off Off or On Power supply failure
On Off Current limit
Note: To ensure that the power supply is operational, both lights must be on.
Chapter 1. Introducing the PC Server 704 13