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NOTE: These components
are affixed
with glue. Be careful
not to break or damage
any foil under
the
component
or at the pins of the Es when removing.
Usually applying
heat to the component
for a short
time while twisting
with tweezers
will break the component
loose.
I
Leadless Chip Components
(surface mount)
Chip components
must
be replaced
with identical
chips due to critical foil track spacing. There are no
holes in the board to mount standard
transistors
or
diodes. Some chip capacitor
or resistor board solder
pads may have holes through the board, however the
hole diameter
limits standard
resistor replacement
to
l/8 watt. Standard
capacitors
may also be limited for
the same reason.
It is recommended
that identical
chip components
be used. .
Chip resistors have a three digit numerical resistance
code -1st and 2nd significant
digits and a multiplier.
Example:
162 = 1600
or 1.6KS1 resistor,
0 = O&J
(jumper).
Chip capacitors
generally
do not have the value
indicated on the capacitor. The color of the component
indicates the general range of the capacitance.
Chip transistors are identified by a two letter code. The
first letter indicates the type and the second letter, the
grade of transistor.
Chip diodes have a two letter identification
code as
per the code chart and are a dual diode pack with
either common anode or common cathode. Check the
parts list for correct diode number.
Component
Removal
1.
Use solder wick to remove solder from component
end caps or terminals.
2.
Without pulling up, carefully twist the component
with tweezers to break the adhesive.
3.
Do
not
reuse
removed
leadless
or
chip
components
since they
are subject
to stress
fracture during removal .
Chip Component
Installation
1.
Put a small
amount
of solder
on the
board
soldering pads.
2.
Hold the chip component
against
the soldering
pads with tweezers
or with a miniature
alligator
clip and apply heat to the pad area with a 30 watt
iron until solder flows. Do not apply heat for more
than 3 seconds
Chip Components
L
1ST DIGIT
How to Replace Flat-IC
-Required
Tools-
* Soldering iron
l
iron wire or small awl
l
De-solder braids
l
Magnifier
I.
Remove the solder from all of the pins of a Flat-IC
by using a de-solder braid.
De-Solder
Braid
Soldering
Iron
2.
Put the iron wire under the pins of the Flat-IC and
pull it in the direction indicated while heating the
pins using a soldering
iron. A small awl can be
used instead of the iron wire.
/
Iron
Wire
Awl
Iron
3.
4.
5.
Remove the solder from all of the pads of the
Fiat-IC by using
a de-solder
braid.
8ti')
Flat-IC
f
-mm-
Position the new Flat-IC in place (apply the pins of
the Flat-IC to the soldering
pads where the pins
need to be soldered). Properly
determine
the positions of the
Polarity
Symbol
soldering
pads and pins by
correctly aligning the polarity
symbol.
:-
Solder all pins to the soldering pads using a fine
tipped soldering iron.
. .
6. Check with a magnifier
for solder bridge between
the pins or for dry joint between
pins and soldering
pads. To remove
a solder
bridge,
use a de-solder
braid as shown in the figure below.
Bridge
Solder
Soldering
Iron
MH DIODE
RESISTOR
10
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