Spare Parts; Standard Parts; Special Parts; Handling Mos Devices - Philips PM 5390 Service Manual

9-1
9
.
SPARE PARTS
9.1.
GENERAL
Standard
Parts
Electrical
and mechanical
parts
replacement can be obtained through your
local Philips organisatioi^
or
representative.
However,
many
of the standard electronic
components
can be obtained
from
other
local
suppliers.
Before purchasing or ordering replacement
parts,
check
the parts
list
for value,
toleran-
ce, rating
and
description.
NOTE:
Physical size
and shape
of a
component
may
affect
instrument performance,
particular!/
at
high frequencies.
Always
use direct-replacement
components,
unless
It is
known
that
a sub-
stitute will
not degrade instrument performance.
Special
Parts
In
addition to the standard electronic
components, some
special
components
are used;
—
Components, manufactured
or selected
by
Philips to
meet
specific
performance
requirements.
—
Components
which
are
important
for the safety
of the instrument marked with
'S'
in
the parts
list.
ATTENTION:
Both type
of
components
may
only be replaced
by components
obtained
through your
local
Philips organisation.
9.2.
STATIC SENSITIVE
COMPONENTS
This instrument contains
electrical
components
that are suspectible to
damage from
static discharge.
Servicing
static-sensitive
assemblies or
components
should be
performed only
at a static-free
work
station
by
qualified service personnel.
9.3.
HANDLING MOS
DEVICES
Though
all
our
MOS
integrated
circuits
incorporate protection against
electrostatic discharges,
they
can
nevertheless
be
damaged by
accidental over-voltages.
In
storing
and
handling
them,
the following
precautions
are
recommended.
CAUTION:
Testing or handling
and mounting
call
for special attention to personal
safety.
Personnel
handling
MOS
devices
should normally
be
connected
to
ground
via a resistor,
9.4.
SOLDERING TECHNIQUES
Working method:
—
Carefully unsolder
one
after
the other the
soldering tags
of the semi-conductor.
—
Remove
all
superfluous soldering material.
Use
a
sucking iron or sucking
litze
wire.
—
Check
that the tags of the
replacement
part are clean
and
pre-tinned
on
the soldering
places.
—
Locate the replacement semi-conductor
exactly
on
its
place,
and
solder each
tag
to the relevant
printed conductor
on
the
circuit
board.
NOTE:
Bear
in
mind
that the
maximum
permissible soldering
time
is
10 seconds during
which
the
temperature
of the tags
must not exceed
250
^C.
The
use of solder with
a
low melting point
is
therefore
recommended.
Take
care
not to
damage
the plastic encapsulation of the semi-conductor
(softening
point
of
the
plastic
Is
150
°C).
ATTENTION: When
you
are soldering inside
the instrument
it is
essential
to use
a
low-voltage
solderir»g
iron, the
tip
of
which must be
earthed
to
ground
of the Instrument.