Hitachi LC57 Service Manual Download

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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 capaci-
tor or resistor board solder pads may have holes through the
board, however the hole diameter limits standard resistor
replacement to 1/8 watt. Standard capacitors may also be
limited for the same reason. It is recommended that identi-
cal 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 1.6K

resistor, 0 = 0

(jumper).

Chip capacitors generally do not have the value indicated on
the capacitor. The color of the component indicates the gen-
eral 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

How to Replace Flat-lC

—Required Tools—

• Soldering iron

• iron wire or small awl

• De-solder braids

• Magnifier

1. Remove the solder from all of the pins of a Flat-lC by

using a de-solder braid.

2. Put the iron wire under the pins of the Flat-lC 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.

3. Remove the solder from all of the pads of the Flat-

lC by using
a de-solder braid.

4. Position the new Flat-lC in place (apply the pins of the

Flat-lC 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.

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.

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.

Chip Components

TYPE

GRADE

SOLDER
CAPS

TRANSISTOR

CAPACITOR

1ST DIGIT

2ND DIGIT

MULTIPLIER
= 1600 = 1.6K

ANODES

MH DIODE

RESISTOR