DEC 4000 AXP Service Manual page 46

Table 2–6 (Cont.) Fixed-Media Mass Storage Problems
Problem Symptom
Missing or loose Cable: storage device to ID
cables panel—Bus node ID defaults to
zero; online LEDs do not come
on.
Flex circuit: LDC to storage
interface module—Disk power
failure LED on PSC is on;
LDC OK LED on storage
compartment front panel is
off; and power-up screen reports
a failing storage adapter port.
Cable: LDC to storage interface
module—Power-up screen
reports a failing storage adapter
port; drive LEDs do not come on
at power-up.
Cable: LDC to storage device—
Drive does not show up in
configuration screen display.
Terminator Read/write errors in console
missing event log; storage adapter port
may fail
No termination DSSI terminator LED is off, or
power no termination voltage measured
at SCSI connector (pin 38,
ground pin 1); Read/write errors;
storage adapter port may fail.
I/O module The storage drawer exhibits no
failure problems when moved to another
compartment.
Backplane Replacing the I/O module does
failure not solve problem. The port
continues to fail and the problem
is not with the storage drawer.
Figures 2–13 and 2–14 provide a flowchart for troubleshooting removable-media
storage problems indicated at power-up. Use the flowchart to diagnose the likely
cause of the problem. Table 2–7 lists the symptoms and corrective action for each
of the possible problems.
2–22 Power-On Diagnostics and System LEDs
Corrective Action
Remove storage drawer and inspect
cable connections.
Attach terminator to connector
port.
Replace LDC (termination power
source for fixed-media storage
compartments).
Replace DC5 converter (termina-
tion power source for storageless
fixed-media storage compartments).
Replace I/O module.
Disassemble system and inspect
backplane interconnect cables. If
the cables and cable connections
do not appear to be the problem,
replace the backplane.