User Manual
ADCP-75-150 • Preliminary Issue A • March 2003 • Section 5: Maintenance
Page 5-19
©
2003,
ADC
Telecommunications,
Inc.
5.5 Linear Power Amplifier Fan Replacement Procedure
The
LPA
is
equipped
with
a
front
and
cooling
fan.
The
front
fan
draws
cool
air
into
the
LPA
enclosure.
Replacement
of
the
fans
requires
that
the
STM
be
turned
off
for
a
short
period
of
time
and
that
the
LPA
be
removed
from
the
cabinet.
Use
the
following
procedure
to
remove
and
replace
the
LPA
cooling
fans.
1. Before
working
on
the
LPA
or
handling
a
fan,
slip
on
an
Electro-Static
Discharge
(ESD)
wrist
strap
and
connect
the
ground
wire
to
an
earth
ground
source.
Wear
the
ESD
wrist
strap
while
completing
each
section
of
the
fan
installation
procedure.
2. Notify
the
NOC
or
alarm
monitoring
system
operator
that
the
system
is
going
offline.
3. Place
the
STM
On/Off
switch
in
the
OFF
position
(press
O).
4. Loosen
the
captive
screws
that
secure
the
LPA
to
the
RU
cabinet/mounting
shelf
and
carefully
withdraw
the
LPA
from
the
cabinet.
5. Pull
out
the
four
retainers
that
secure
the
front
fan
to
the
LPA
as
shown
in
Figure 5-7
and
same
for
reuse.
Figure 5-7. LPA Fan Removal and Replacement
6. Carefully
withdraw
the
fan
assembly
from
the
LPA
until
the
wiring
harness
is
exposed
and
the
RJ-45
wiring
harness
connector
is
accessible.
7. Disconnect
the
fan
wiring
harness
connector
from
the
LPA
and
lift
the
fan
assembly
away
from
the
LPA.
8. Place
a
small
amount
of
anti-corrosion
gel
on
the
connector
of
the
replacement
fan
assembly.
9. Orient
the
fan
assembly
so
the
air-flow
arrow
points
into
the
LPA.
Warning:
Electronic
components
can
be
damaged
by
static
electrical
discharge.
To
prevent
ESD
damage,
always
wear
an
ESD
wrist
strap
when
working
on
the
HU,
STM,
or
LPA
and
when
handling
electronic
components.
Drawing
not
available