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2
Service notes
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 ICs when removing. Usually applying heat to the
component for a short time while twisting with tweezers will
break the component loose.
Leadless chip component (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
chips
capacitor or resistor board solder pads may have holes
through
the
board,
however
the
hole
diameter
limits
standard
resistor
replacement
to
1/8
watt.
Standard
capacitor may also be limited for the same
reason.
It is
recommended that identical components be used.
Chip resistor have a three digit numerical resistance code,
1st and 2nd significant digits and a multiplier. Example: 162
- 1600 or 1.6КО resistor, 0 - 00 (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 terminal.
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 оп 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
ТҮРЕ
SOLDER
ЕСІ
САР5
b
TRANSISTOR
CAPACITOR
TSTDIGIT ,— oup DIGIT
COMMON
су CATHODE
MULTIPLIER
21600 = 1.6k
<
ANODES <?
SOLDER
CAPS
MH DIODE
RESISTOR
©
How to replace flat іс (required tools)
1. Remove the solder from all of the pins of a Flat ІС by
using a desolder braid
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 ам! can be used instead of the
iron wire.
Soldering
iron
3. Remove the solder from all the pads of the Flat IC by
using a de solder braid
X.
Ду
De-soldering
Et
"ч
© Braid
ra. 4657
у,
Soldering
AN Iron
4. Position the new Flat IC in place (apply the pins of the
Flat ІС to the soldering pads where the pins need to be
soldered).
Properly
determine
the
positions
of the
soldering pads and pins by correctly aligning the polarity
symbol
2nd solder
ist solder
Polarity
symbol
5. Solder all pins to the soldering pads using a fine tipped
soldering iron
Soldering
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
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