Table of Contents
Advertisement
Replacement
Parts:
If
you have
difficulty
finding
parts
for
this
or
any
other
Orban
product,
Orban
Customer
Service
stands
ready
to
supply
you with
the
required
parts at a
fair price.
Please
call
us
at
the
telephone
number shown
at
the
front of
this
Manual.
Replacement
of
Components
on
Printed
Circuit
Boards
It
is
important
to
use the correct technique
for
replacing
components mounted
on
PC
boards.
Failure
to
do
so
will
result
in
possible
circuit
damage
and/or
intermittent problems.
The
circuit boards used
in
the
424A
are
of
the double-sided plated-through variety.
This
means
that
there are traces on both
sides of
the board,
and
that
the through-
holes
contain
a
metallic
plating
in
order
to
conduct
current
through the board.
Because
of
fhe plated-through
holes, solder
often creeps
1/16"
up
into
the
hole,
requiring a sophisticated technique
of
component
removal
to
prevent
serious
damage
to the
board.
Removal:
If
the
technician
has
no
practical
experience
with
the
elegant
and
demanding
technique
of
removing componenfs from
double-sided
PC
boards wifhouf
board damage,
if
is
wiser
to cut
each
of
the
leads of
an
offending
componenf from
its
body
while the
leads
are
still
soldered
into the
board.
The component
is
then
discarded, and each
lead
is
heated independently and
pulled out of the
board with
long nose
pliers.
Each
hole
may
then be cleared
of solder
by
carefully heating
with
a
low-wattage
soldering
iron
and sucking
out the
remaining
solder
with a
spring-
activated desoldering
tool.
THIS
METHOD
IS
THE
ONLY
SATISFACTORY
METHOD
OF CLEARING A
PLATED-THROUGH HOLE
OF SOLDER!
Another
technique
is:
1)
Use
a 30 watt
soldering
iron
to
melt
the
solder
on
the solder (underneath)
side
of
fhe
PC
board.
Do
not use a soldering
gun
or
a
high-wattage
iron!
As
soon
as
the
solder
is
molten,
vacuum
it
away
with
a
spring-actuated
desoldering
tool
like
the Edsyn
"Soldapullt".
AVOID
OVERHEATING THE
BOARD;
overheating
will
almost
surely
damage
the
board
by
causing
the
conductive
foil
to
separate
from
fhe board.
Use
a pair
of
fine
needle-nose
pliers fo
wiggle the
lead horizontally
until
it
can be observed
to
move
freely
in
the
hole.
2)
Repeat
step
(I)
until
each
lead to
be
removed
has
been
cleared
of
solder
and
freed.
3)
Now
lift
the
component
out.
Installation:
1)
Bend
the leads
of
fhe
replacement
component
until
it
will
fit
easily into
the
appropriate
PC
board
holes.
Using
a
good
brand
of
rosin-core
solder,
solder
each
lead
to
the
bottom
side
of
the
board with a 30 watt
soldering
iron.
Make
sure
that the
joint
is
smooth and
shiny.
If
no
damage
has
been done
to
the
plated-through
hole,
soldering
of
the
topside
pad
is
not
necessary.
However,
if
the
removal procedure
did
not
progress
smoothly,
it
would
be
prudent
to solder
each
lead at
the topside
as well
in
order
to
avoid
potential
intermittent problems.
2)
Cut
each
lead of fhe
replacement
component
close to the solder
(underneath)
side of the
PC
board with
a pair
of
diagonal cutters.
29
Hide quick links:
Advertisement
Table of Contents
