Panasonic CT-25G5UB Service Manual - Page 4
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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 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 1.6kΩ resistor, 0 = 0Ω (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
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
TYPE
GRADE
c
b
e
TRANSISTOR
COMMON
CATHODE
ANODES
SOLDER
CAPS
MH DIODE
Service Notes
leadless
or
chip
SOLDER
CAPS
CAPACITOR
1ST DIGIT
2ND DIGIT
MULTIPLIER
=1600 = 1.6k
RESISTOR
How to Replace Flat-IC
- Required Tools -
•
Soldering iron
•
Iron wire or small awl •
1. Remove the solder from all of the pins of a Flat-IC
by using a de-solder braid.
Flat-IC
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.
Pull
3. Remove the solder from all the pads of the Flat-IC
by using a de-solder braid.
Flat IC
4. 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 soldering pads and pins by
correctly aligning the polarity symbol.
5. Solder all pins to the soldering pads using a fine
tipped soldering iron.
Solder
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.
Solder
Bridge
- 4 -
•
De-solder braids
Magnifier
De-Solder
Braid
Iron
Wire
Soldering
Soldering
Iron
Iron
Soldering
Iron
De-Solder
Braid
Polarity Symbol
Soldering
Iron
De-Solder
Braid
Soldering
Iron
Awl