User's Manual

ADCP-75-187 • Issue 1 • September 2005 • Section 4: MAINTENANCE

Page 4-10

PROBLEM D: The forward path VSWR is above threshold.

POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS

1. Faulty antenna or antenna system.

2. Faulty antenna cable.

3. The RU quadraplexer has failed.

1. Check the antenna system for shorts or opens

(including lightning protector). To reset, use

EMS to place Digivance system in standby mode

and then place system back in normal mode.

2. Check the antenna cable for faulty connections.

3. Replace the RU.

PROBLEM E: No light received over the forward path or excessive errors received over the forward path

POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS

1. Faulty forward path optical fiber.

2. Faulty optical transmit port at the HU;

or faulty optical receive port at the RU.

1. Test optical fiber. Clean connector if dirty. Repair

or replace optical fiber if faulty. (See Section 4.1).

2. Test HU optical transmit port. Replace HU if port

is faulty. Replace RU if HU transmit port is OK.

(see Section 4.2).

PROBLEM F: The RU does not respond to control or monitoring commands sent by the EMS.

POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS

1. The cable connection between the HU and

the EMS computer is faulty.

1. Inspect EMS cable and repair or replace if faulty.

PROBLEM G: No RF power is detected at the RU quadraplexer.

POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS

1. No RF power is being input to the HU or the

RF input signal level at the HU is too low.

2. The RU (LPA) is faulty.

1. Check the RF input power level at the HU and

adjust until within specifications.

2. Replace RU.

PROBLEM H: The RF output form the RU (LPA) is shut down.

POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS

1. The LPA is in the forced shutdown mode.

2. The RU (LPA) is faulty.

1. Check for fault conditions that will cause a major

alarm. Correct faults as required. To reset, use

EMS to place Digivance system in standby mode

and then place system back in normal mode

2. Replace RU.

Table 4-6. Remote Unit Fault/Alarm Corrective Action, continued