• There are some special components used in LCD
monitor that are important for safety. These parts are
marked on the schematic diagram and
the Exploded View.It is essential that these
critical parts should be replaced with the
manufacturer’s specified parts to prevent electric
shock, fire or other hazard.
• Do not modify original design without obtaining written
permission from manufacturer or you will void the
original parts and labor guarantee.
TAKE CARE DURING HANDLING THE LCD MODULE
WITH BACKLIGHT UNIT.
• Must mount the module using mounting holes arranged
in four corners.
• Do not press on the panel, edge of the frame strongly
or electric shock as this will result in damage to the
screen.
• Protect the module from the ESD as it may damage the
electronic circuit (C-MOS).
• Make certain that treatment person’s body is
grounded through wrist band.
• Do not leave the module in high temperature and in
areas of high humidity for a long time.
• The module not be exposed to the direct sunlight.
• Avoid contact with water as it may a short circuit within
the module.
• If the surface of panel become dirty, please wipe it off
with a soft material. (Cleaning with a dirty or rough cloth
may damage the panel.)
CAUTION
Please use only a plastic screwdriver to protect yourself
from shock hazard during service operation.
WARNING
BE CAREFUL ELECTRIC SHOCK !
• If you want to replace with the new backlight (CCFL)
or inverter circuit, must disconnect the AC
adapter because high voltage appears at inverter
circuit about
650Vrms.
• Handle with care wires or connectors of the
inverter circuit. If the wires are pressed cause short
and may burn or take fire.
• Be careful while tilting and rotating the monitor to
avoid pinching hand(s)
CAUTION: Before servicing receivers covered by this
service manual and its supplements and addenda, read
and follow the SAFETY PRECAUTIONS on page 3 of this
publication.
NOTE:
between the following servicing precautions and any of the
safety precautions on page 3 of this publication, always
follow the safety precautions. Remember: Safety First.
If unforeseen circumstances create conflict
General Servicing Precautions
1. Always unplug the receiver AC power cord from the AC
power source before;
a. Removing or reinstalling any component, circuit
board module or any other receiver assembly.
b. Disconnecting or reconnecting any receiver electrical
plug or other electrical connection.
c. Connecting a test substitute in parallel with an
electrolytic capacitor in the receiver.
CAUTION: A wrong part substitution or incorrect
polarity installation of electrolytic capacitors may
result in an explosion hazard.
d. Discharging the picture tube anode.
2. Test high voltage only by measuring it with an
appropriate high voltage meter or other voltage
measuring device (DVM, FETVOM, etc) equipped with a
suitable high voltage probe.
Do not test high voltage by "drawing an arc".
3. Discharge the picture tube anode only by (a) first
connecting one end of an insulated clip lead to the
degaussing or kine aquadag grounding system shield
at the point where the picture tube socket ground lead is
connected, and then (b) touch the other end of the
insulated clip lead to the picture tube anode button,
using an insulating handle to avoid personal contact
with high voltage.
4. Do not spray chemicals on or near this receiver or any of
its assemblies.
5. Unless specified otherwise in this service manual,
clean electrical contacts only by applying the following
mixture to the contacts with a pipe cleaner, cottontipped stick or comparable non-abrasive applicator;
10% (by volume) Acetone and 90% (by volume)
isopropyl alcohol (90%-99% strength)
CAUTION: This is a flammable mixture.
Unless specified otherwise in this service manual,
lubrication of contacts in not required.
6. Do not defeat any plug/socket B+ voltage interlocks
with which receivers covered by this service manual
might be equipped.
7. Do not apply AC power to this instrument and/or any of
its electrical assemblies unless all solid-state device
heat sinks are correctly installed.
8. Always connect the test receiver ground lead to the
receiver chassis ground before connecting the test
receiver positive lead.
Always remove the test receiver ground lead last.
9. Use with this receiver only the test fixtures specified in
this service manual.
CAUTION: Do not connect the test fixture ground strap
to any heat sink in this receiver.
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid-state) devices can be
damaged easily by static electricity. Such components
commonly are called Electrostatically Sensitive (ES)
Devices. Examples of typical ES devices are integrated
circuits and some field-effect transistors
and semiconductor "chip" components. The
fol l o wi n g techniques should be used to help reduce the
incidence of component damage caused by static by static
electricity.
1. Immediately before handling any semiconductor
component or semiconductor-equipped assembly, drain
off any electrostatic charge on your body by touching a
known earth ground. Alternatively, obtain and wear a
commercially available discharging wrist strap device,
which should be removed to prevent potential shock
reasons prior to applying power to the unit under test.
2. After removing an electrical assembly equipped with
ES devices, place the assembly on a conductive
surface such as aluminum foil, to prevent electrostatic
charge buildup or exposure of the assembly.
3. Use only a grounded-tip soldering iron to solder or
unsolder ES devices.
4. Use only an anti-static type solder removal device.
Some solder removal devices not classified as "antistatic" can generate electrical charges sufficient to
damage ES devices.
5. Do not use freon-propelled chemicals. These can
generate electrical charges sufficient to damage ES
devices.
6. Do not remove a replacement ES device from its
protective package until immediately before you are
ready to install it. (Most replacement ES devices are
packaged with leads electrically shorted together by
conductive foam, aluminum foil or comparable
conductive material).
7. Immediately before removing the protective material
from the leads of a replacement ES device, touch the
protective material to the chassis or circuit assembly
into which the device will be installed.
CAUTION: Be sure no power is applied to the chassis
or circuit, and observe all other safety precautions.
8. Minimize bodily motions when handling unpackaged
replacement ES devices. (Otherwise harmless motion
such as the brushing together of your clothes fabric or
the lifting of your foot from a carpeted floor
can generate static electricity sufficient to damage an
ES device.)
5
General Soldering Guidelines
1. Use a grounded-tip, low-wattage soldering iron and
appropriate tip size and shape that will maintain tip
temperature within the range or 500。F to 600。F.
2. Use an appropriate gauge of RMA resin-core solder
composed of 60 parts tin/40 parts lead.
3. Keep the soldering iron tip clean and well tinned.
4. Thoroughly clean the surfaces to be soldered. Use a
mall wire-bristle (0.5 inch, or 1.25cm) brush with a
metal handle.
Do not use freon-propelled spray-on cleaners.
5. Use the following unsoldering technique
a. Allow the soldering iron tip to reach normal
temperature.
(500。F to 600。F)
b. Heat the component lead until the solder melts.
c. Quickly draw the melted solder with an anti-static,
suction-type solder removal device or with solder
braid.
CAUTION: Work quickly to avoid overheating the
circuitboard printed foil.
6. Use the following soldering technique.
a. Allow the soldering iron tip to reach a normal
temperature (500。F to 600。F)
b. First, hold the soldering iron tip and solder the strand
against the component lead until the solder melts.
c. Quickly move the soldering iron tip to the junction of
the component lead and the printed circuit foil, and
hold it there only until the solder flows onto and
around both the component lead and the foil.
CAUTION: Work quickly to avoid overheating the
circuit board printed foil.
d. Closely inspect the solder area and remove any
excess or splashed solder with a small wire-bristle
brush.
IC Remove/Replacement
Some chassis circuit boards have slotted holes
(oblong) through which the IC leads are inserted and
then bent flat against the circuit foil. When holes are
the slotted type, the following technique should be
used to remove and replace the IC. When working
with boards using the familiar round hole, use the
standard te c h n i q u e a s outlined in paragraphs 5 and 6
above.
Removal
1. Desolder and straighten each IC lead in one
operation by gently prying up on the lead with the
soldering iron tip as the solder melts.
2. Draw away the melted solder with an antista tic suction-type solder removal device (or with
solder braid) before removing the IC.
Replacement
1. Carefully insert the replacement IC in the circuit board.
2. Carefully bend each IC lead against the circuit foil pad
and solder it.
3. Clean the soldered areas with a small wire-bristle
brush. (It is not necessary to reapply acrylic coating to
the areas).
1. Remove the defective transistor by clipping its leads as
close as possible to the component body.
2. Bend into a "U" shape the end of each of three leads
remaining on the circuit board.
3. Bend into a "U" shape the replacement transistor leads.
4. Connect the replacement transistor leads to the
corresponding leads extending from the circuit board
and crimp the "U" with long nose pliers to insure metal
to metal contact then solder each connection.
Power Output, Transistor Device
Removal/Replacement
1. Heat and remove all solder from around the transistor
leads.
2. Remove the heat sink mounting screw (if so equipped).
3. Carefully remove the transistor from the heat sink of the
circuit board.
4. Insert new transistor in the circuit board.
5. Solder each transistor lead, and clip off excess lead.
6. Replace heat sink.
Diode Removal/Replacement
1. Remove defective diode by clipping its leads as close
as possible to diode body.
2. Bend the two remaining leads perpendicular y to the
circuit board.
3. Observing diode polarity, wrap each lead of the new
diode around the corresponding lead on the circuit
board.
4. Securely crimp each connection and solder it.
5. Inspect (on the circuit board copper side) the
solder joints of the two "original" leads. If they are not
shiny, reheat them and if necessary, apply additional
solder.
Fuse and Conventional Resistor
Removal/Replacement
1.
Clip each fuse or resistor lead at top of the circuit
board hollow stake.
2. Securely crimp the leads of replacement
component around notch at stake top.
3. Solder the connections.
CAUTION: Maintain original spacing between
the replaced component and adjacent components
and the ci r cuit board to prevent excessive
component temperatures.
Excessive heat applied to the copper foil of any
printed circuit board will weaken the adhesive that
bonds the foil to the circuit board causing the foil to
separate from or
"lift-off" the board. The following guidelines
and procedures should be followed whenever this
condition is encountered.
At IC Connections
To repair a defective copper pattern at IC connections
use the following procedure to install a jumper wire
on the copper pattern side of the circuit board.
(Use t h i s technique only on IC connections).
1. Carefully remove the damaged copper pattern with
a sharp knife. (Remove only as much copper
a s absolutely necessary).
2. carefully scratch away the solder resist and
acrylic coating (if used) from the end of the
remaining copper pattern.
3. Bend a small "U" in one end of a small gauge
jumper wire and carefully crimp it around the IC pin.
Solder the IC connection.
4. Route the jumper wire along the path of the outaway copper pattern and let it overlap the previously
scraped end of the good copper pattern. Solder the
overlapped area and clip off any excess jumper wire.
At Other Connections
Use the following technique to repair the defective
copper pattern at connections other than IC Pins. This
technique i nvo l v es th e ins t alla t i on o f a jump e r
wire on the component side of the circuit board.
1. Remove the defective copper pattern with a
sharp knife.
Remove at least 1/4 inch of copper, to ensure that
a hazardous condition will not exist if the jumper
wire opens.
2. Trace along the copper pattern from both sides of
the pattern break and locate the nearest component
that is directly connected to the affected copper
pattern.
3. Connect insulated 20-gauge jumper wire from the
lead of the nearest component on one side of the
pattern break to the lead of the nearest
component on the other side.
Carefully crimp and solder the connections.
CAUTION: Be sure the insulated jumper wire
is dressed so the it does not touch components or
sharp edges.