Service Manuals, User Guides, Schematic Diagrams or docs for : LG TV 21FU8AZ lg_21fu8-az_chassis_cp-079b
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COLOR TV
SERVICE MANUAL
CHASSIS: CP-079B
CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
CONTENTS
Contents 2
Location & Function of control 3
Safety Precautions 4
Specifications 7
Adjustment 9
Block Diagram 15
R,G,B Section / Deflection Section 16
Audio AMP. Section 17
Exploded View 18
Exploded View Parts List 19
Replacement Parts List 20
Schematic Diagram
2
Location and function of controls
All the functions can be controlled with the remote control handset. Some functions can
also be adjusted with the buttons on the front panel of the set.
Remote control handset
Before you use the remote control handset, please install the batteries. See the
previous page.
1. POWER
switches the set from On to standby or standby to On.
2. NUMBER BUTTONS
switches the set On from standby or directly select a Programme number.
3. MENU
selects a menu.
POWER MUTE
4. EYE/ * (option)
switches the eye function On or Off.
1 9
5. / (Programme Up/Down)
1 3
2 selects a programme or a menu item.
switches the set On from standby.
4
5
6
(Volume Up/Down)
2 adjusts the volume.
7
8
9 adjusts menu settings.
OK accepts your selection or displays the current mode.
PSM
0 SSM/*
6. Q. VIEW
7 14 returns to the previously viewed programme.
US
IC/EQ
R
AMA/AR
7. PSM (Picture Status Memory)
M
15
C
D
recalls your preferred picture setting.
*
S/
/WOO EW M
19 ES
M
N
I
MO V
FE
R*
17 8. XDP (option)
18 Select Excellent Digital Picture.
SLEEP MENU
13 3 9. MUTE
PR switches the sound On or Off.
10. TV/AV
VOL OK VOL selects TV or AV mode.
5
switches the set On from Standby.
11. I/II/ (option)
PR
TV/AV EYE/*
selects the language during dual language broadcast. (option)
10 4 selects the sound output in AV mode.
12. LIST/X-LIST* (option)
LIST/X-LIST*
USB/* Q-VIEW
12 displays the programme table. press LIST key again to clear the LIST table from
21 the screen.
6
FAV/X-SORT* XDS/* XDP
13. SLEEP
16 8 sets the sleep timer.
l/ll/* 20 14. SSM (option) (Sound Status Memory)
11 recalls your preferred sound setting.
15. ARC (option)
change picture format (Normal/Zoom).
16. FAVOURITE (OPTION) / X-SORT (option)
pressing each time this button will select a stored favourite programme. X-SORT
switches X- SORT (option) On/Off.
17. MM (option)
select music mode.
18. Woofer(option)
direct access key for woofer on/off.
19. EQ/* (option)
direct access key to select EQ (Graphics Equalizer).
20. XDS/* (option)
selects excellent digital surround.
21. USB/* (option)
to enter into USB mode.
COLOURED BUTTONS : When Menu is On some of these buttons are used
for programme edit.
Remarks : 1. Some keys in remote can be non-functional, these keys are used in
other models. 2. Keys marked * are non functional.
# Remote Design / Aesthetic may vary from model to model.
3
SAFETY PRECAUTIONS
IMPORTANT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the
Schematic Diagram and Replacement Parts List.
It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent X-
RADIATION, Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.
General Guidance Before returning the receiver to the customer,
An Isolation Transformer should always be used during the always perform an AC leakage current check on the exposed metallic
servicing of a receiver whose chassis is not isolated from the AC parts of the cabinet, such as antennas, terminals, etc., to be sure the
power line. Use a transformer of adequate power rating as this set is safe to operate without damage of electrical shock.
protects the technician from accidents resulting in personal injury
Leakage Current Cold Check (Antenna Cold Check)
from electrical shocks.
With the instrument AC plug removed from AC source connect an
It will also protect the receiver and it's components from being electrical jumper across the two AC plug prongs. Place the AC switch
damaged by accidental shorts of the circuitary that may be in the on position, connect one lead of ohm-meter to the AC plug
inadvertently introduced during the service operation. prongs tied together and touch other ohm-meter lead in turn to each
exposed metallic parts such as antenna terminals, phone jacks, etc.
If any fuse (or Fusible Resistor) in this TV receiver is blown, replace it If the exposed metallic part has a return path to the chassis, the
with the specified. measured resistance should be between 1MW and 5.2MW.
When the exposed metal has no return path to the chassis the
When replacing a high wattage resistor (Oxide Metal Film reading must be infinite.
Resistor, over 1W), keep the resistor l0mm away from PCB. An other abnormality exists that must be corrected before the
receiver is returned to the customer.
Keep wires away from high voltage or high temperature parts.
Leakage Current Hot Check (See below Figure)
Due to high vacuum and large surface area of picture tube, extreme Plug the AC cord directly into the AC outlet.
care should be used in handling the Picture Tube. Do not lift the Do not use a line Isolation Transformer during this check.
Picture tube by it's Neck. Connect 1.5K/10watt resistor in parallel with a 0.15uF capacitor
between a known good earth ground (Water Pipe, Conduit, etc.) and
X-RAY Radiation the exposed metallic parts.
Measure the AC voltage across the resistor using AC voltmeter with
Warning:
1000 ohms/volt or more sensitivity.
Reverse plug the AC cord into the AC outlet and repeat AC voltage
The source of X-RAY RADIATION in this TV receiver is the measurements for each esposed metallic part. Any voltage
High Voltage Section and the Picture Tube. measured must not exceed 0.75 volt RMS which is corresponds to
For continued X-RAY RADIATION protection, the 0.5mA.
replacement tube must be the same type tube as specified In case any measurement is out of the limits sepcified, there is
in the Replacement Parts List. possibility of shock hazard and the set must be checked and repaired
before it is returned to the customer.
Leakage Current Hot Check circuit
To determine the presence of high voltage, use an accurate high
impedance HV meter.
AC Volt - meter
Adjust brightness, color, contrast controls to minimum. Measure the
high voltage.
The meter reading should indicate
23.5 .5KV: 14-19 inch, 26 1.5KV: 19- 21 inch,
29.0 1.5KV: 25-29 inch, 30.0 1.5KV: 32 inch,
Good Earth Ground
If the meter indication is out of tolerance, immediate service and
such as WATER PIPE,
correction is required to prevent the possibility of premature CONDUIT etc.
0.15uF
component failure. To Instrument's
exposed
METALLIC PARTS
1.5 Kohm10W
4
SERVICING PRECAUTIONS
CAUTION: Before servicing receivers covered by this service manual transistors and semicounductor "chip" components. The following
and its supplements and addenda, read and follow the SAFETY techniques should be used to help reduce the incidence of
PRECAUTIONS on page 3 of this publication. component damage caused by static by static electricity.
NOTE: If unforeseen circumstances create conflict between the 1.Immediately before handling any semiconductor component or
following servicing precautions and any of the safety precautions on semiconductor-equipped assembly, drain off any electostatic
page 3 of this publication, always follow the safety precautions. charge on your body by touching a known earth ground.
Remember: Safety First. Alternatively, obtain and wear a commercially available
discharging wrist strap device, which should be removed to
General Servicing Precautions prevent potential shock reasons prior to applying power to the unit
1. Always unplug the receiver AC power cord from the AC power under test.
source before; 2.After removing an electrical assembly equipped with ES devices,
a. Removing or reinstalling any component, circuit board module place the assembly on a conductive surface such as aluminum foil,
or any other receiver assembly. to prevent electrostatic charge buildup or exposure of the
b.Disconnecting or reconnecting any receiver electrical plug or
assembly.
other electrical connection. 3.Use only a grounded-tip soldering iron to solder or unsolder ES
c.Connecting a test substitute in parallel with an electrolytic
devices.
capacitor in the receiver. 4.Use only an anti-static type solder removal device. Some solder
CAUTION: A wrong part substitution or incorrect polarity
removal devices not classified as "anti-static" can generate
installation of electrolytic capacitors may result in an explosion
electrical charges sufficent to demage ES devices.
hazard. 5.Do not use freon - propelled chemicals. These can generate
d. Discharging the picture tube anode.
electrical charges sufficient to damage ES devices.
2. Test high voltage only by measuring it with an appropriate high 6.Do not remove a repalcement ES device from its protective
voltage meter or other voltage measuring device (DVM, FETVOM, package until immediately before you are ready to install it. (Most
etc) equipped with a suitable high voltage probe. Do not test high replacement ES devices are packaged with leads electrically
voltage by "drawing an arc". shorted together by conductive foam, aluminum foil or comparable
3. Discharge the picture tube anode only by (a) first connecting one conductive material).
end of an insulated clip lead to the degaussing or kine aquadag 7.Immediately before removing the protective material from the
grounding system shield at the point where the picture tube socket ieads of a replacement ES device, touch the protective material to
ground lead is connected, and then (b) touch the other end of the the chassis or circuit assembly into which the device will be
insulated clip lead to the picture tube anode button, using an installed.
CAUTION: Be sure no power is applied to the chassis or circuit,
insulating handle to avoid personal contact with high voltage.
4. Do not spray chemicals on or near this receiver or any of its and observe all other safety precautions.
8. Minimize bodily motions when handling unpackaged replacement
assemblies.
5. Unless specified otherwise in this service manual, clean electrical ES devices. (Otherwise harmless motion such as the bruching
contacts only by applying the following mixture to the contacts with together of your clothes fabric or the lifting of your foot from a
a pipe cleaner, cotton-tipped stick or comparable nonabrasive carpeted floor can generate static electricity sufficient to damage
applicator; 10% (by volume) Acetone and 90% (by volume) an ES device.)
isopropyl alcohol (90%-99% strength)
General Soldering Guidelines
CAUTION: This is a flammable mixture. 1.Use a grounded-tip, low-wattage soldering iron and appropriate tip
Unless specified otherwise in this service manual, lubrication of size and shape that will maintan tip temperature within the range or
contacts in not required. 500◦ Jabse Service Manual Search 2024 ◦ Jabse Pravopis ◦ onTap.bg ◦ Other service manual resources online : Fixya ◦ eServiceinfo