Service Manuals, User Guides, Schematic Diagrams or docs for : LG TV cf-20e60 M64AAI

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M64AAI

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ADJUSTMENT INSTRUCTIONS

* Safety precautions * VCO (Voltage Controlled Oscillator)
Adjustment
1. It is safe to adjust after using insulating transformer
between the power supply line and chassis input to Test Point :
JP4(L504)
prevent the risk of electric shock and protect the
instrument. Adjust :
VL501
2. Never disconnect leads while the TV receiver is on.
3. Don't short any portion of circuits while power is on.
4. The adjustment must be done by the correct appliances. 1) Turn on DC power supplies.
But this is changeable in view of productivity. 2) Adjust VCO ADJ. coil(L501) so that the level of Picture
5. Unless otherwise noted, set the line voltage to 220Vac+_ Carrier (PC) may be at the lowest position as shown Fig.
20%, 50/60Hz. 2.

*Test Equipment required SC (Sound Carrier)
: 32.5 MHz
1. Swee p Generator
2. Marker Generator(38.0MHz: Picture/32.5MHz: Sound)
3. Alignmen t Scope(5121A)
4. Patter n Generator(PAL/SECAM)
5. DC Power Supply
6. Color analyzer
7. Multimeter(Volt meter) PC (Picture Carrier)
: 38.0 MHz

Preparation for VCO Adjustment Fig. 2: Output waveform on Alignment Scope
1. Connect the measuring equipment to the TV as shown in
Fig. 1
2. Set RF output level of Sweep Generator to 90dBuV. NOTE: When performing this adjustment, if there are 2
adjusted point in VL501, select the lower core
position.

* RF AGC (Auto Gain Control)
MAIN BOARD Adjustment
C533
(JP 3)

Z101 Test Point :J9(AGC ADJ.) or Observing Display
(JP 1) 48

5
IC501 Adjust :VR501
7
CK 3.3K IC401
0.01uF L504

(JP 4) The RF AGC control VR501 was aligned at the time of
1
VL501
manufacture for optimum performance over a wide range
(JP 6)
TUNER VCO ADJ. conditions. Readjust VR501 should not be necessary
J9
AGC unless unusual local conditions exist, such as;
ADJ.

1) Channel interference in a CATV system
RF
out 2) Picture bending and/or color beats, which are unusually
Hor DC POWER DC POWER due to excessive RF signal input when the reciever is
SWEEP S.G Alignment SUPPLY SUPPLY
with Marker Scope too close to a transmitting tower or when the receiver
Ver 5.0 + 0.1V 16 + 0.5V
is connected to an antenna distribution system where
the RF signal has been amplified.
In this case, the input signal should be attenuated(with
pad or filter) to a satisfactory level.
Fig. 1: Connection Diagram of Equipment for VCO Adjustment
3) Picture noise caused by "broadcast noise" or weak
signal.
If the broadcast is "clean" and the RF signal is at least
1mV (60dBu), the picture will be noise free in any area.

- 1 -
Adjusting the VR501(RF AGC) control to one end of * Scr een & White Balance
rotation will usually cause a relatively poor signal to noise
ratio;
(color temperature) Adjustment
Adjusting to the other end of rotation will usually cause a
NOTE: 1. This adjustment should be performed after
degradation of over load capabilities resulting on color
warming up for 20 minutes.
beats or adjacent channel interference.
2. The color bias controls (VR901, VR902, VR903)
For the best results, adjust VR501 contol while
affect the low light (dark) area of the picture
performing on all other local channels, or Refer to the
while the color drive controls (VR904, VR905)
following Table 1.
affect the high light (white) areas.

Tuner P/N Maker Adjustment Voltage REMARK 1) Set all the controls (VR901-VR905) on CPT Board to
113-118C/D/F LG-ALPS 5.7+_0.1Vdc RF 60+_1dBuV geometric center position.
2) Set the standard mode (contrast : 80, bright : 60, color : 50).
113-238H LG-ALPS 6.0+_0.1Vdc RF 60+_1dBuV
3) Set the AV mode, adjust and set the screen volume of
6700VMV001A SANYO 4.9+_0.1Vdc RF 60+_1dBuV FBT at just cut-off position(No AV input signal).
4) Set the TV mode, tune the TV set to receive white

pattern.
5) By using color analyzer (white balance checker), adjust
X position equals to 281+_8 and Y position equals to 288
* Vertical Height, Center Adjustment +_8, it means that color temperature is 10,000+_800 at
low light (4.5ftL) and high light (over 45ftL).
Test Poin t : Observing display

Adjust : VR30 (Vertical Height)
1
VR302 (Vertical Center)

1) Tune the TV set to receive a digital test pattern.
2) Set standard picture mode(contrast: 80, bright :60,
color: 50).
3) Adjust the Vertical height control (VR301) so that the
circle of a digital test pattern may be located within
the effective screen of the CPT.
4) Adjust the Vertical center control (VR302) for
obtaining geometric center of valuable display
vertically.

* Focus A djustment
NOTE: This adjustment should be performed after
warming up for 10 minutes.

Test Poin t : Observing display

Adjust : Focus control of FBT

1) Tune the TV set to receive a digital test pattern.
2) Adjust the Focus control for the best overall focus.

* Horizontal Center Adjustment
Test Poin t : Observing display

Adjust : VR502

1) Tune the TV set to receive a PAL digital pattern.
2) Adjust the Horizontal center control(VR502) for
obtaining geometric center of valubale display
horizontally.

- 2 -
PURITY & CONVERGENCE ADJUSTMENT

Caution:
Convergence and Purity have been factory aligned. Do not 5. Reconnect the internal degaussing coil.
attempt to tamper with these alignments.
However, the effects of adjacent receiver components, or 6. Position the beam bender locking rings at the 9 o'clock
replacement of picture tube or deflection yoke may require the position and the other three pairs of tabs (2,4 and 6 pole
need to readjust purity any convergence. magnets) at the 12 o'clock position.

DEFLECTION YOKE 6-POLE
PURITY &CONVERGENCE 6-POLE
MAGNETS
MAGNES PURITY MAGNET(2-POLE)
MAGNET ASSEMBLY

6-POLE

,,,,
,,,, ,
,,,, ,
,,,, , ,
,,,,
,,,,
,,,, 4-POLE
X-AXIS YOKE MAGNET
,
,,,, , ,,,,
,,,, , ,, ,
,, ,,
,,,, , ,, ,,
,,,, , ,
,,,,
,, , POSITIONING
(L/R PURITY)
RUBBER
WEDGES PURITY MAGNET
4-POLE
GLASS CLOTH TAPE CONVERGENCE MAGNET ASSEMBLY
CONVERGENCE MAGNET ASSEMBLY

* Purity Adjustment

This procedure DOES NOT apply to bonded yoke and picture 7. Perform the following steps, in the order given, to prepare the
tube assemblies. receiver for the purity adjustment procedure.
The instrument should be at room temperature (60 degrees F or
above) for six (6) hours and be operating at low beam current a. Face the receiver in the "magnetic north" direction.
(dark background) for approximately 20 to 30 minutes before
performing purity adjustments. b. Externally degauss the receiver screen with the television
power turned off.
CAUTION: Do not remove any trim magnets that may be
attached to the bell of the picture tube. c. Turn the television on for approximately 10 seconds to
perform internal degaussing and then turn the TV off.
1. Remove the AC power and disconnect the internal
degaussing coil. d. Unplug the internal degaussing coil. This allows the
thermistor to cool down while you are performing the purity
2. Remove the yoke from the neck of the picture tube. adjustment. DO NOT MOVE THE RECEIVER FROM ITS
"MAGNETIC NORTH" POSITION.
3. If the yoke has the tape version beam bender, remove it and
replace it with a adjustable type beam bender (follow the e. Turn the receiver on and obtain a red raster by increasing
instructions provided with the new beam bender) the red bias control (CW) and decreasing the bias controls
for the remaining two colors (CCW).
4. Replace the yoke on the picture tube neck, temporarily
remove the three (3) rubber wedges from the bell of the f. Attach two round magnets on the picture tube screen at 3
picture tube and then slide the yoke completely forward. o'clock and 9 o'clock positions, approximately one (1) inch
from the edge of the mask (use double-sided tape).

3-2
1.ADJUST YOKE Z-AXIS FIRST 2 .ADJUST BEAM BENDER 2 POLE
TO GET EQUAL BLUE MAGNET TO GET FOUR EQUAL
COLOR CIRCLES COLOR CIRCLES

MAGNETS

RED RED

8. Referring to above, perform the following two steps: 6. Reconnect the internal degaussing coil and apply AC power.
a. Adjust the yoke Z-axis to obtain equal blue circles.
b. Adjust the appropriate beam bender tabs to obtain correct 7. Turn the receiver on for 10 seconds to perform internal
purity (four equal circles). degaussing and then turn the receiver off again.

9. After correct purity is set, tighten the yoke clamp screw and 8. Unplug the internal degaussing-coil.
remove the two screen magnets.
9. Turn on the receiver, connect a signal generator to the VHF
10. Remove the AC power and rotate the receiver 180 degrees antenna terminal and apply a crosshatch signal.
(facing "magnetic south").
Caution: During the convergence adjustment procedure, be
11. Reconnect the internal degaussing coil. very careful not to disturb the purity adjustment tabs
are accidentally move, purity should be confirmed
12. Turn the receiver on for 10 seconds (make sure the receiver before proceeding with the convergence adjustments.
came on) to perform internal degaussing, and then turn the
receiver off. Note: Make sure the focus is set correctly on this instrument
before proceeding with the following adjustment.
13. Unplug the internal degaussing coil.
10. Converge the red and blue vertical lines to the green vertical
14. Turn on the receiver and check the purity by holding one (1) line at the center of the screen by performing the following
round magnet at the 3 o'clock and a second round magnet at steps (below TABLE).
9 o'clock position. If purity is not satisfactory, repeat steps 8 a. Carefully rotate both tabs of the 4-pole ring magnet
through 14. simultaneously in opposite directions from the 12 o'clock
position to converge the red and blue vertical lines.
15. Turn off the receiver and reconnect the internal degaussing b. Carefully rotate both tabs of the 6-pole ring magnet
coil. simultaneously in opposite directions form the 12 o'clock
position to converge the red and blue (now purple)
vertical lines with the green vertical line.
* Convergence Adjustment
11. Converge the red and blue horizontal with the green line at
Caution: This procedure DOES NOT apply to bonded yoke and the center of the screen by performing the following steps.
picture tube assemblies. (below TABLE)
Do not use screen magnets during this adjustment a. Carefully rotate both tabs of the 4-pole ring magnet
procedure. Use of screen magnets will cause an simultaneously in the same direction (keep the spacing
incorrect display. between the two tabs the same) to converge the red and
blue horizontal lines.
1. Remove AC power and disconnect the internal degaussing b. Carefully rotate both tabs of the 6-pole ring magnet
coil. simultaneously in same direction (keep the spacing
between the two tabs the same) to converge the red and
2. Apply AC Power and set the brightness to the Picture Reset blue (now purple) horizontal lines with the green
condition. Set the Color control to minimum. horizontal line.
c. Secure the tabs previsouly adjusted by locking them in
3. Apply 8V to the pin. place with the locking tabs on the beam bender.

4. Adjust the Red, Green and Blue Bias controls to get a dim
white line.

5. Remove the AC power and 8V from the pin.

3-3
RING ROTATION DIRECTION MOVEMENT OF RED
PAIRS OF BOTH TABS AND BLUE BEAMS

B B
OPPOSITE OR
R R
4
POLE

SAME B R OR B R

B B
OPPOSITE OR
R R
6
POLE

SAME B R OR B R

UP/DOWN ROCKING OF THE YOKE LEFT/RIGHT ROCKING OF THE YOKE
UP/DOWN ROCKING OF THE YOKE
CAUSES OPPOSITE ROTATION OF RED CAUSES OPPOSITE SIZE CHANGE YOKE
LEET/RIGHT ROCKING OF THE OF THE
AND BLUEOPPOSITE ROTATION OF RED
CAUSES RASTERS RED AND BLUE RASTERS CHANGE OF
CAUSES OPPOSITE SIZE
AND BLUE RASTERS THE RED AND BLUE RASTERS

GREEN

GREEN
ADJUSTMENT
VIEWING ADJUSTMENT RED
AREA BLUE RED VIEWING
AREA
RED

GREEN RED BLUE

BLUE RED
GREEN

RED BLUE

TV
SCREEN

GREEN

12. While watching the 6 o'clock positions on the screen, rock the 17. Temporarily place a rubber wedge at the 5 o'clock and 7
front of the yoke in a vertical (up/down) direction to converge o'clock positions to hold the horizontal position of the yoke.
the red and blue vertical lines. (Fig upper left) 18. Check the 3 o'clock and 9 o'clock areas to confirm that the
13. Temporarily place a rubber wedge at the 12 o'clock position red and blue vertical lines are converged. If the lines are not
to hold the vertical position or the yoke. converged, slightly offset the horizontal tilt of the yoke (move
14. Check the 3 o'clock and 9 o'clock areas to confirm that the red the temporary rubber wedges if necessary) to equally
and blue horizontal lines are converged. balance the convergence error of the horizontal lines at 6
If the lines are not converged, slightly offset the vertical tilt of the o'clock and 12 o'clock and the vertical lines at 3 o'clock and 9
yoke (move the rubber wedge if necessary) to equally balance the o'clock.
convergence error of the horizontal lines at 3 o'clock and 9 o'clock 19. Using a round magnet confirm purity at the center, right and
and the vertical lines at 6 o'clock and 12 o'clock. left sides and corners. See Purity Adjustment Procedure.
15. Place a 1.5 inch piece of glass tape over the rubber foot at 20. Reconfirm convergence and apply a 1.5 inch piece of glass
the rear of the 12 o'clock wedge. tape over the rubber foot at the rear of the 5 o'clock and the 7
16. While watching the 6 o'clock and 12 o'clock areas of the o'clock wedges.
screen, rock the front of the yoke in the horizontal (left to
right) motion to converge the red and blue horizontal lines.
(Fig. upper right)

3-4

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