User's Manual

ADCP-75-158 • Issue 1 • July 2003 • Section 5: Maintenance

Page 5-6

3.1 Host Unit Troubleshooting

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.

It is recommended that whenever there are multiple alarms, the optical alarms should be

checked and cleared first. Because the host and remote units function as a system, a fault in the

fiber optic link will cause various unit alarms to be reported.

Table 5-6. Remote Unit Minor Alarms

MINOR ALARM LED INDICATOR MINOR ALARM LED INDICATOR

Temperature STM Sec Laser Fail (Does not apply)

Sec Rev Mux Lock (Does not apply) Sec Rev Synth Lock (Does not apply)

Rev Path Level (Does not apply) LPA Disable STATUS (LPA)

LPA Fan PA LPA High Temp PA

Minor Extern Alarm Inp (Does not apply) RF Out Very Low (Does not apply)

Table 5-7. Host Unit Fault Isolation and Troubleshooting

LED: POWER Color: Off Alarm Type: Major

PROBLEM: The HU is not powered.

POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS

1. The fuse is open or removed from the fuse

panel.

1. Replace or reinstall fuse at fuse panel.

LED: STANDBY Color: Green (blinking) or

Yellow (blinking)

Alarm Type: None

PROBLEM: The HU is out of service.

POSSIBLE CAUSE CORRECTIVE ACTION/COMMENTS

1. The HU is in the standby (green) or program

load (yellow) mode.

1. Use EMS to place the HU in the normal (off)

mode.

LED: HOST UNIT Color: Yellow Alarm Type: Minor

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).