User Manual

ADCP-75-136 • Issue 1 • November 2002
Page 47
© 2002, ADC Telecommunications, Inc.
Table 12. DEU Fault Isolation and Troubleshooting Guidelines (Continued)
Alarm Type LED LED COLOR
Major OK/NOK Red
Problem: The DEU is receiving a major alarm signal from the connected DRU.
POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS
1. Faulty forward path optical fiber between DEU
and DRU.
2. Faulty optical transmit port at DEU or faulty
optical receive port at DRU.
3. The connected DRU is faulty.
1. Clean optical connector and then test optical fiber.
Repair or replace if faulty (see Subsection 6.4.2).
2. Make sure transceiver is fully plugged in and then
test optical port. Replace optical transceiver if
port is faulty (see Subsection 6.4.1).
3. Check DRU STATUS indicator and then refer
to appropriate troubleshooting section for
procedures.
Table 13. DRU Fault Isolation and Troubleshooting Guidelines
Alarm Type LED LED COLOR
Major STATUS Off
Problem : The DRU is not powered.
POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS
1. DC power cable open.
2. No power or insufficient power output from
ac/dc power converter, DHU (1), or DEU (2).
3. Faulty DRU.
1. Test cable for continuity and repair or replace if
faulty.
2. Check DC voltage level at the DRU (see Subsection
6.4.3). Replace converter, DHU, or DEU (whichever
applies) if voltage is not within 34 to 48 Vdc.
3. Replace DRU.
Alarm Type LED LED COLOR
Major STATUS Blinking Red
Problem : The DRU is not receiving an optical signal from the DHU or DEU; or the DHU or DEU is not receiving
an optical signal from the DRU.
POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS
1. Faulty forward or reverse path optical fiber
between DHU and DRU (1), DEU and
DRU (2), or DEU and DHU (2).
2. Faulty optical transmit or receive port at the
DHU (1) or DEU (2); or faulty optical
transmit or receive port at DRU (1 and 2).
1. Clean optical connector and then test optical fiber.
Repair or replace if faulty (see Subsection 6.4.2).
2. Make sure transceiver is fully plugged it and then
test optical port. Replace optical transceiver if
port is faulty (see Subsection 6.4.1).
Alarm Type LED LED COLOR
Major STATUS Red
Problem: The DRU detects an internal circuitry fault.
POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS
1. Faulty DRU. 1. Replace DRU.