Troubleshooting guide

MX2820 System Manual
7-96 61186003L1-1D
CAUTION
Electronic modules can be damaged by static electrical discharge.
Before handling modules, wear an antistatic discharge wrist strap
to prevent damage to electronic components. Place modules in
antistatic packing material when transporting or storing. When
working on modules, always place them on an approved antistatic
mat that is electrically grounded.
PROCEDURE
1. Connect to the craft port for the shelf being tested. For details, refer to DLP-715.
2. Logon to the system. For details, refer to DLP-716.
3. Go to the shelf’s Master Alarm log.
a. From the MX2820 system Main Menu, select SYSTEM ALARMS and press ENTER.
b. From the System Alarms menu, select ALARM LOGS.
c. Check the Master Alarms log to verify that no active alarm is indicated for the Fan
Module. The Fan Module failure alarm is generated when the AUX3 input is set to act
as a fan alarm, and the AUX3 input receives an alarm signal. The name of the fan
alarm is user definable with the User Definable menu.
d. If an alarm is indicated, check to make sure the Fan Module is powered and working. If
the Fan Module is operating, but an alarm is still present, check the wiring between the
Fan Module and the MX2820 shelf to verify the wiring is correct. For details, refer to
DLP-711.
Take corrective action to clear the alarm before proceeding.
4. Locate the fuse in the fuse panel that feeds the Fan Module being tested.
CAUTION
Verify the fuse is the correct fuse. Pulling the wrong fuse can
remove power from an active transmission system and result in
service-affecting problems.
5. Use the fuse extractor, if necessary to remove the Fan Module fuse from the fuse panel. If
no fuse panel fuse exists for the Fan Module, remove the fuse from the rear of the Fan
Module instead.
6. Check the System Alarm log to verify that an active alarm appears which has the
description associated with the AUX3 fan failure. Verify that the alarm level matches the
user-definable level assigned during the installation procedure. Minor is the default level
for this alarm. If an alarm does not appear, check the alarm wiring between the Fan
Module and the MX2820 shelf. For details, refer to DLP-711.
7. Re-install the Fan Module fuse.