Instruction manual

A fan-and-power-supply assembly has the following lights and switch:
AC PWR light 1
The AC PWR light, which is green, comes on when the mainline power supply
is connected to the fan-and-power-supply assembly.
DC PWR light 2
The DC PWR light, which is green, comes on when this fan-and-power-supply
assembly is supplying power to the 2104.
CHK light 3
The CHK light, which is amber, indicates either that there is a failure in the
fan-and-power-supply assembly or that the DC On/Standby switch is set to
Standby.
Note: This light flashes when the failure in the fan-and-power-supply assembly
is a fan failure.
DC On/Standby switch 4
The DC On/Standby switch connects dc electrical power from the
fan-and-power-supply assembly to the disk drives and other components in the
2104. This switch must be set to on for the fan-and-power-supply unit to start.
If the DC On/Standby switch on either of the two fan-and-power-supply
assemblies is set to on, power in a 2104 Model DU3 or TU3 unit is switched
on automatically if all of the following conditions exist:
v Input power to the 2104 is present.
v The fan-and-power-supply assembly is fully home in its slot.
Figure 8. Fan-and-Power-Supply Assembly Lights and Switch
12 2104 Models DU3 and TU3 Operator’s Guide