User Manual

AS4000 Operations and Maintenance

Section

605-0000-431

. Issue 1.6. Date3/2/99

DLP-012

Page 42 of 44 © Copyright Airspan Communications Corporation 1999

STEP PROCEDURE

Observe full ESD precautions.

1. Press Receive Attention on the modem shelf cover to suppress alarm.

2. Use a DMM to check the output of the PSU at the voltage test output on the PSU

front panel. The output should measure 13.5V ±100mV

3. If the output is present but an alarm still exists the monitor circuit within the PSU is

likely to be faulty. Change the PSU. The PSUs operate in redundant mode.

Removing a PSU will not affect the operation of the rack. Use the ring pull at the

front of the PSU to assist with removal. Replace the card ensuring that the PSU is

located within the shelf card guides.

4. If there is no output change the PSU.

5. Use a DMM to check the output of the new PSU at the voltage test output on the

PSU front panel. The output should measure 13.5V ±100mV

6. If after changing the PSU alarm still exists then check that the voltage is present on

the input to the PSU as it is most likely that there is a backplane fault. If the

backplane is faulty change the Combiner Shelf.

STOP. THIS PROCEDURE HAS BEEN COMPLETED.