User's Manual

Lucent Technologies — Proprietary
See notice on first page
401-660-100 Issue 11 August 2000
22-9
Linear Amplifier Circuit (LAC) Maintenance
determine if the LAC has issued a Processor alarm. A LAC should not be replaced
for a MINOR alarm if it has not issued a processor alarm
*
.
Low-level Thermal alarms indicate that the LAC is beginning to overheat.
Overheating may be caused by the LAC being overdriven or may be due to a
Linear Amplifier Unit (LAU) fan failure or a cell site air conditioning failure. This
type of alarm is seldom encountered. See Thermal Alarm Procedure.
NOTE:
If the LAC has not issued a processor alarm and over-heating has been
ruled out, an intermittent MINOR alarm was most likely caused by an LAM.
It is often difficult to identify LAMs which alarm only a few times in one day.
Since a failed LAM is not service affecting, it may be best to continue to
monitor the LAC from the MSC and return to the site if the alarms become
more frequent.
MAJOR Alarms
MAJOR alarms are, in order of likelihood:
■
Preamp alarms
■
Multiple LAMs in alarm
■
a blown Final Correction Amplifier (FCA) fuse
■
a failed fan (C-Series LACs)
■
a mid-level thermal alarm.
A major alarm, particularly a continuous alarm, indicates that the LAC is operating
in a condition which may be service affecting, or may soon become so. Although
the LAC output power may be reduced (due to a bad preamp or a blown preamp
fuse), service should not be completely interrupted due to a MAJOR alarm
condition.
* Except for A/B-Series LACs with a LAM Bias Fault. See LAM Bias Fault Procedure.