User Manual

ADCP-75-179 • Preliminary Issue A • September 2004 • Section 4: maintenance

Page 4-14

DISPLAY MESSAGE FORCED/INTERNAL SHUTDOWN Alarm Type: OVER POWER ALARM

PROBLEM: Output power from the LPA exceeds the maximum rating.

POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS

1. The power level of the RF forward path

composite input signal at the HU is too high.

2. The LPA has failed.

1. Check the power level of the RF composite input

signal at the HU and adjust to correct level. To

reset, use EMS to place Digivance system in

standby mode and then place system back in

normal mode.

2. Replace LPA.

DISPLAY MESSAGE FORCED/INTERNAL SHUTDOWN Alarm Type: VSWR ALARM

PROBLEM: The VSWR exceeds threshold setting of 3:1.

POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS

1. The interface cable between the LPA and STM

is faulty or the interface cable connectors are

faulty.

2. The antenna cable or antenna cable connectors

are faulty.

3. The antenna or antenna system is faulty.

4.The STM qudraplexer has failed.

5. The LPA has failed.

1. Inspect interface cable and connectors and repair

or replace as needed.To reset, use EMS to place

Digivance system in standby mode and then place

system back in normal mode.

2. Inspect antenna cable and connectors and repair

or replace as needed.To reset, use EMS to place

Digivance system in standby mode and then place

system back in normal mode.

3. Check the antenna circuit 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.

4. Replace STM.

5. Replace LPA

Table 4-8. 35 Watt LPA Fault Isolation and Corrective Action, continued