Digital Equipment RW504-ZA, Service Manual

Page: 78 / 220

4.7 Recovery from Hardware Errors
When a hardware failure occurs, a message is displayed on the control panel.
If the failure occurs during the power-on sequence,
FAIL 1 is displayed. If the
failure occurs at some other time, MISLOAD or FAIL 0 is displayed. If a failure
occurs while you are running a test, FAIL # is displayed, where # is the number of
the test that failed.
When you press
ENTER
, the autochanger displays information about the
hardware failure.
The autochanger firmware can detect broken components such as a dead motor,
a missing belt, etc., but if failures are due to marginal or random problems, the
failing component may induce errors in other components. For example, if any
portion of the electronics becomes intermittent or if friction increases on a part,
different components of the autochanger may appear to fail at varied points as
the autochanger runs its code. This results in many different error codes.
Note
Instructions for running internal diagnostic tests are given in Section 4.9.
A list of the available test choices and their descriptions are given in
Section 4.10.
4.7.1 Hardware Error Codes and Recovery Procedures
Table 4–3 shows the hardware error codes possible and recovery procedures for
specific hardware errors.
In all cases, if you run a test and no error occurs, monitor for reoccurrence. If the
error repeats, use the list of FRUs logged by the FRU isolation test as a guide to
determine the problem. Replace the FRU(s) as necessary.
4–20 Troubleshooting and Diagnostics