User Manual

ADCP-75-126 • Issue B • April 2002 • Section 5: Maintenance
Page 5-7
© 2002, ADC Telecommunications, Inc.
During normal HU operation, all LED’s should be green except the STANDBY LED which
should be Off. When a Minor alarm occurs, one or more of the LED’s will turn yellow. When a
Major alarm occurs, one or more of the LED’s will turn red.
Table 5-6. Remote Unit Minor Alarms
MINOR ALARM LED INDICATOR MINOR ALARM LED INDICATOR
Temperature STM Sec Laser Fail STM
Sec Rev Mux Lock STM Sec Rev Synth Lock STM
Rev Path Level (Does not apply) LPA Disable SHUTDOWN (LPA)
LPA Fan PA LPA High Temp PA
Minor Extern Alarm Inp (Does not apply) RF Out Ve r y Low (Does not apply)
Table 5-7. Host Unit Fault Isolation and Troubleshooting
Alarm Type LED Color
Minor HOST UNIT Yellow
PROBLEM: The HU is overheating.
POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS
1. Air intake or exhaust opening to HU chassis
is blocked
2. Ambient temperature > 50º C/122º F.
3. Faulty fan.
1. Remove cause of air-flow blockage.
2. Reduce ambient temperature.
3. Replace HU fan (See Section 5.3).
Alarm Type LED Color
Minor REMOTE UNIT Yellow
PROBLEM: A minor alarm is detected at the RU.
POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS
1. The STM or LPA is overheating. 1. Check RU for alarms and refer to Table 5-8
Alarm Type LED Color
Minor DRIVE Yellow
PROBLEM: The RF input signal level is below the underdrive threshold.
POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS
1. Faulty coaxial connection between the
HU and the BTS.
2. Incorrect attenuation in forward path RF coax-
ial link.
1. Check forward path signal level at the HU.
2. Check Host Forward Attenuator setting and
adjust if attenuation is too high.