DEC 4000 AXP Service Manual page 29

Table 2–1 (Cont.) Interpreting Power Supply LEDs
Indicator Meaning
Power System Controller (PSC)
PSC OK When blinking, indicates the
PSC is performing power-up
self-tests.
When steady, indicates the PSC
is functioning normally.
PSC Failure When lit, indicates the PSC has
detected a fault in itself.
Disk Power When lit, indicates a disk
Failure power problem for the storage
compartment specified in the
hexadecimal fault ID display.
The most likely failing unit is
the local disk converter, but a
shorting cable or drive could also
be at fault.
Fan Failure When lit, indicates a fan has
failed or a cable guide is not
properly secured. The failure is
identified by a number displayed
in the hexadecimal fault ID
display.
Overtemperature When lit, indicates the PSC has
Shutdown shut down the system due to
excessive internal temperature.
Action on Error
Replace power system controller
(Chapter 5).
To isolate the local disk converter,
disconnect the drives on the
specified bus and then power
up the system. If the Disk Power
Failure LED lights with the drives
disconnected, replace the failing
local disk converter (Chapter 5).
Refer to Figure 2–2 to locate the
local disk converter specified by
the fault ID display. A is the top
compartment, D is the bottom
compartment.
Refer to Figure 2–2 to locate the
failure specified by the fault ID
display.
Replace the failing fan (Chapter 5).
Set the AC circuit breaker to off (0)
and wait one minute before turning
on the system.
Make sure the air intake is
unobstructed and that the room
temperature does not exceed
maximum requirement as
described in the DEC 4000 Site
Preparation Checklist.
(continued on next page)
Power-On Diagnostics and System LEDs 2–5