User Manual

PBL UHF 1 & 2 Air Interface
Maintenance Handbook
H/book Number:-60-055900HBKM
Issue No:-1
Date:-13/02/2003
Page:-80 of 80
5) If the amplifier to be removed has a heatsink attached, there may be several different ways
it can have been assembled. The most commonly used method, is screws through the front
of the heatsink to threaded screw holes (or nuts and bolts), into the amplifier within the
main case. If the heatsink is mounted on the rear of the main case (e.g., against a wall in
the case of wall mounted enclosures), then the fixing method for the heatsink will be from
within the case, (otherwise the enclosure would have to be removed from the wall in order
to remove the heatsink).
When the heatsink has been removed, the amplifier may be unscrewed from the main
casing by its four corner fixings and gently withdrawn.
Fitting a new power amplifier module will be the exact reverse of the above.
Note: Do not forget to apply fresh heatsink compound to the heatsink/main case
joint and also between the amplifier and the main case.
7.3.5 Low Power Amplifier Replacement
1 Disconnect the mains power supply and disconnect the 24V dc supply connector for the
LPA.
2 Disconnect the RF input and output cables from the LPA.
3 Disconnect the alarm connector.
4 Remove the alarm monitoring wires from (D type connector) pins 9 and 10.
5 Remove the LPA module by removing the four retaining screws, replace with a new LPA
module and secure it with the screws.
6 Connect the RF cables to the LPA input and output connectors. Reconnect the wires to
the alarm board connector pins 9 and 10.
7 Reconnect the DC supply connector and turn the mains switch on.
Note: Tighten SMA connectors using only a dedicated SMA torque spanner. If
SMA connectors are over-tightened, irreparable damage will occur. .
Do not use
adjustable pliers to loosen/tighten SMA connectors.
Also take care not to drop or knock the module as this can damage (or misalign in the
case of tuned passive modules) sensitive internal components. Always store the modules
in an environmentally friendly location
7.3.6 Module Transportation:
To maintain the operation, performance and reliability of any module it must be stored and
transported correctly. Any module not installed in a whole system must be kept in an anti-
static bag or container. These bags or containers are normally identified by being pink or
black, and are often marked with an ESD label. Any module sent back to AFL for
investigation/repair must be so protected. Please contact AFL’s quality department before
returning a module.