Huawei Airbridge cBTS3612 Maintenance Manual page 59

On-site Maintenance Manual
Airbridge cBTS3612 CDMA Base Station
The fault elimination process should be carried out step by step,
go directly to next step if the problem can not be solved:
Re-plug the BHPA, make sure it is secured in place and
l
connected to the backplane properly. Tighten the screws;
Check if the cable on the backplane connecting the BTRM
l
and BHPA, BHPA and the CDU (or DFU, DDU), power
source and the BHPA are getting loose or pulled off.
Check if the B HPA module is damaged.
If the BHPA is powered properly, the cable/connector are intact
and the signal input is normal while the BHPA still has no RF signal
output, the BHPA must be damaged and needs to be replaced.
II.
Abnormal RF signal output
The Abnormal RF signal output of the BHPA means the output
power is lower than the rated value, the Adjacent Channel Power
Ratio (ACPR) of the output signal is above the acceptable level.
The main causes are: 1) the Power Amplifier gain is decreasing;
2) some of the Power Amplifier components are damaged; 3) power
output is too high. Abnormal Power Amplifier gain decrease will
generate relevant alarms; and if the input/output power is too high, it
will cause the Power Amplifier output spectrum to spread and the
ACPR to get above the acceptable level.
The gain decrease alarm indicates the working status of the
amplification channel of the BHPA. The alarm threshold is 3~6dB of
the power-amplification gain decrese. When the BHPA gain decreses
up to 6dB, an alarm will be generated; if it drops to 3dB or below, the
Chapter 3 Component Failure
3-22
Handling