IBM 6H0, Service Manual

Page: 102 / 561

Symptom Action
The system does not respond to the password
being entered or the system login prompt is
displayed when booting in service mode.
1. If the password is being entered, or the
service mode boot is being initiated, on a
keyboard attached to the system, then the
keyboard or its controller may be faulty. In
this case, replace these parts in the
following order:
a. Keyboard
b. Primary I/O backplane, location:
U0.1-P1
2. If the password is being entered, or the
service mode boot is being initiated, from
an ASCII terminal, first insure that the
terminal is connected to S1 or S2. Use the
problem determination procedures for the
ASCII terminal.
If the problem persists, replace the primary
I/O backplane, location: U0.1-P1.
No codes are displayed on the operator panel
within a few seconds of turning on the system.
The operator panel displays OK before the
system is powered on.
Reseat the operator panel cable. If problem not
resolved, replace in order:
1. Operator panel assembly. Swap the VPD
module.
2. Primary I/O backplane. (See notes on 75.)
The SMS configuration list or boot sequence
selection menu shows more SCSI devices
attached to a controller/adapter than are
actually attached.
A device may be set to use the same SCSI bus
ID as the control adapter. Note the ID being
used by the controller/adapter (this can be
checked and/or changed via an SMS utility),
and verify that no device attached to the
controller is set to use that ID.
If settings do not appear to be in conflict:
1. Replace the SCSI cable.
2. Replace the device.
3. Replace the SCSI adapter
Note: In a
″
twin-tailed
″
configuration where
there is more than one initiator device (normally
another system) attached to the SCSI bus, it
may be necessary to use System Management
Services to change the ID of the SCSI
controller or adapter.
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Service Guide