Flowchart For Troubleshooting Fixed-Media Problems (Continued) - DEC 4000 AXP Service Manual

Figure 2–12 Flowchart for Troubleshooting Fixed-Media Problems (Continued)
Are cables loose or missing?
Power down, remove drawer and check all cable connections, reseat drawer and power up.
Problems persist
Continue
Is the storage bus terminated?
Check that a terminator is in place.
Terminator present
Check that terminator power is present. For DSSI buses, check that the terminator LED is on.
For SCSI buses use a volt meter on the port connector (termination power is supplied by pin 38,
ground on pin 1).
Power present
Continue
Is the I/O module the source of the problem?
Swap the failing drive drawer to another compartment.
Problems persist
Likely problem with drive, drawer, or cables. Check again before continuing.
Is the backplane the source of the problem?
Eliminate all of the preceding problem sources before suspecting the backplane.
The backplane is the least likely to fail.
Disassemble the system as described in Section 5.4. Inspect the two
backplane interconnect cables.
Cables are OK Cable connections are
loose or damaged
Replace backplane assembly as described in Section 5.4.
2–20 Power-On Diagnostics and System LEDs
Problems solved Cable disconnected
Terminator missing Terminator missing
No termination power -
-
Problems solved I/O module failure
Backplane interconnect cable failure
LDC failure (with fixed-media devices)
DC5 failure (for storageless fixed-media
compartments)
LJ-02548-TI0B