Alcatel-Lucent MDR-8000 User Manual page 74

Errors are being received by the RCVR at a rate exceeding the Eye
BER threshold error rate provisioned on the radio configuration
screen. This alarm could be caused by a faulty XMTR (farend), radio
interference on the RF path (RFI), antenna/waveguide problem, or a
faulty antenna/waveguide problem, or a faulty RCVR/RCVR local
oscillator failure. Troubleshooting is configuration dependent.
1. Check for Eye Closure alarms on both A and B RCVRs.
Are there Eye Closure alarms on both A and B RCVRs?
Yes, go to 2.
No, only A or B has an Eye Closure alarm. The failure is on
the RCVR end. Go to 3.
2. The problem is in the farend XMTR, is an RF path problem, or is
a farend or local antenna/waveguide problem. Start by isolating the fault to one end of the hop or the RF
path/antenna/waveguide.
a. Check farend for XMTR alarms. Troubleshoot and clear alarms (if any) at far end as required. Go to b.
b. Check farend radio XMTR configuration as follows:
Hot-standby XMTRs? Go to c.
Frequency diversity? Go to 4.
Space diversity? Troubleshoot farend XMTR.
c. If the farend XMTR is hot-standby, switch XMTRs and see if alarms at the RCVR end clear.
Do RCVR alarms clear?
Yes, the problem is at the XMT end and the path and RCV end are ok. Replace farend off-line XMTR.
No, the problem is a path problem or a problem at the RCVR. Go to d to isolate the path.
d. The problem may be RF interference (RFI) on the path. While observing the RSL on the RCV end Analog
screen, disable the farend XMTRs.
Does RSL drop at least 25 dB?
No, there is high RFI on the path. Eliminate the RFI source.
Yes, RSL drops 25 dB or more. The problem is a path problem, such as an obstruction in the path, or
a problem with the antenna or waveguide, or is a RCVR problem. Go to 3.
3. Isolate failure to RCVR crystal oscillator subboard or the RCVR module as follows:
a. At RCV end, observe RX (AFC MON ) voltage on the analog monitor screen. This is the correction
voltage for the crystal oscillator. The voltage should be -3.0 ±0.5 Vdc, indicating that the crystal oscillator
is on center frequency.
If not, remove and replace crystal oscil
If the RX (AFC MON) voltage is correct, replace RCVR module.
Do RCVR alarms clear?
Yes, stop. Procedure is complete.
No, go to 4.
4. Problem is in path (not RFI) or antenna/waveguide. Sweep waveguide at both ends of hop. Repair or replace
as required.
Figure 5 - 6 Troubleshooting Radio RCV Alarms (Sheet 4 of 5)
5-16
STATUS
Receiver Fault
Receiver On Line
Channel Fail
Eye Closure
Low RSL
Path Distortion
Radio Frame Loss
Radio Dade
lator subboard on RCVR.
RECEIVER
A
MDR-1082
11/29/04