User Manual

ADCP-75-110 • Issue 2B • July 2001
Page 49
© 2001, ADC Telecommunications, Inc.
Table 11. Fault Isolation and Troubleshooting, continued
Alarm Type None
LED Indicators DHU, DEU, and DRU: All LEDs are green.
Problem Loss of phone service from one DRU. Service normal at all other DRUs.
POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS
1. DRU antenna cable disconnected.
2. DRU antenna obstructed or misdirected.
3. DRU antenna faulty.
4. DRU faulty.
1. Re-connect DRU antenna cable to DRU.
2. Remove antenna obstruction or re-orient antenna.
3. Replace antenna.
4. Replace DRU.
Alarm Type None
LED Indicators DHU, DEU, and DRU: All LEDs are green
Problem Loss of phone service from all DRUs.
POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS
1. Faulty coaxial connection between DHU
and the LIU or RIU.
2. Faulty coaxial connection between LIU and
the BTS or RIU and donor antenna.
3. Faulty LIU or RIU.
4. Faulty DHU
5. Fault with cellular network or equipment.
1. Check forward path signals at the DHU. Check
reverse path signals at the LIU or RIU.
2. Check forward path signals at the LIU or RIU.
Check reverse path signals at the BTS or antenna.
3. Adjust or replace LIU or RIU.
4. Replace DHU.
5. Contact cell service provider and verify that
cellular network and equipment is operational.
Alarm Type None
LED Indicators DHU, DEU, and DRU: All LEDs indicate normal operation.
Problem Calls may be originated and terminated but service is noisy.
POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS
1. Some electrical device in the immediate
vicinity is creating interference.
1. Try turning off each device that may be causing
interference and see if problem corrects itself.
Alarm Type None
LED Indicators DHU, DEU, and DRU: All LEDs indicate normal operation.
Problem Sudden high rate of blocked calls (delay dial tone).
POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS
1. Too many users for the number of channels
available.
2. Faulty DHU, DEU, or DRU.
1. Wait a few minutes and try dialing again. Upgrade
service if additional channels are required.
2. Replace defective unit.
Alarm Type None
LED Indicators DHU: OVERDRIVE - Red
Problem Forward path RF input level too high.
POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS
1. Incorrect attenuation in forward path RF
coaxial link.
1. Adjust attenuation at RIU or LIU.