Product data
Fan-and-Power-Supply Assembly Lights and Switch
To identify the lights and switch that are described here, see Figures 2 and 3.
DC On/Standby switch 10: This switch switches off the dc electrical power to the
disk drive modules and other components of the 2104. The switch must be set to On
for the power supply and the fan unit to start.
If the DC On/Standby switch is set to On (on either fan-and-power-supply assembly, if
two are present), dc power in the 2104 is turned on automatically if all the following
conditions exist:
v Mainline power is present at the 2104.
v At least one fan-and-power-supply assembly is correctly installed.
v Either the Power Control switch on the Switch card assembly is set to On or
terminator power is active in an external SCSI connection.
CHK light 11: This amber light is on continuously if the fan-and-power-supply
assembly fails or goes into Standby mode. When a power supply fails, the CHK light
gets its power from the other fan-and-power-supply assembly (if present). The light can,
therefore, indicate a critical power supply failure only if the 2104 has two
fan-and-power-supply assemblies.
Note: The CHK light is active only when the DC On/Standby switch is set to On.
DC PWR light 12: This green light is on when the power supply assembly is
supplying dc power to the 2104.
AC PWR light 13: This green light is on when mainline electrical power is present in
the power supply assembly.
Fan Assembly Light
To identify the light that is described here, see Figures 2 and 3.
CHK light 8: This amber light comes on if the fan fails.
8 2104 Service Guide