Motorola VSWR, Service Manual Supplement

Page: 44 / 44

Maintenance procedures
5th Feb 99
3–2
Service Manual Supplement: VSWR Monitor for M-Cell 6
68P02900W86-O
Maintenance procedures
Maintenance
philosophy
The maintenance philosophy for the VM is to replace a defective unit with a new VM.
The VM does not contain any user-serviceable parts and defective units should be
returned to Motorola for repair.
Replacing a
defective VM
Safety precautions
Read through the information contained in Warnings and cautions at the beginning of
this document. This equipment must only be removed and replaced by suitably qualified
personnel.
Disable the transmitter RF power in the BTS sector to be fitted with the VM by using lock
device commands from the OMC or via a PC connected to the MCU. Check that the
orange Tx STATUS LEDs on the relevant TCUs are not lit before starting to disconnect
the RF cables.
Removal procedure
The procedure for removing a VM is as follows:
1. Disconnect the –48 V dc supply from the VM.
2. Disconnect the alarm cable from the VM.
3. Label all RF cable connections to the VM and then disconnect the cables.
4. Undo the mounting screws/bolts and remove the VM. Note the positions of the
cable loss compensation jumpers.
Replacement procedure
The replacement procedure is a reversal of the removal procedure. Remember to set the
cable loss compensation jumpers on the new VM to the same positions as on the
defective VM.
Testing
Once installed, the new VM must be tested as described in Testing the VM.