Service Manuals, User Guides, Schematic Diagrams or docs for : LG TV cf-28a50f pc58aai
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ADJUSTMENT INSTRUCTIONS
* Safety Precautions Frequency Modulation Output level
1. It is safe to adjust after using insulating transformer
38.9MHz OFF 10mVp-p
between the power supply line and chassis input to
prevent the risk of electric shock and protect the (Table 1)
instrument.
2. Never disconnect leads while the TV receiver is on.
3. Don't short any portion of circuits while power is on. * SECAM L' Adjustment
4. The adjustment must be done by the correct
appliances. But this is changeable in view of NOTE : This adjustment should be performed after PIF
productivity. adjustment.
5. Unless otherwise noted, set the line voltage to 230Vac
+_10%, 50Hz.
Test Point : TP1
* Test Equipment required Adjust : VR101
1. RF signal generator (with pattern generator)
2. DC Power Supply
3. Multimeter (volt meter) 1) Tune the TV set to receive a SECAM-L' signal.
4. Oscilloscope 2) Adjust VR101 so that the DC voltage may be indicated
5. Color analyzer 2.6+_0.1Vdc.
Main Board(Component side view)
* SECAM L/L' sound Adjustment
MULTIMETER Test Point : C638(Refer to the Fig.2)
MAIN BOARD
Adjust : VL102
TDA9811 VR101
L'
17 16 ADJ.
TP1
23 TP2
VL102
4.5M 9 OSCILLOSCOPE IC601
TP3 IC101 MSP3410
VL101 30 C638
PIF 1
32
VR102
55 AM INPUT
38.9MHz AGC
10mVp-p ADJ. J116
RF SIGNAL 5 61
GENERATOR CERAMIC CAP. Z102 GND
4
10000pF
(TP point is on the
CERAMIC CAP.
copper side of PCB)
TUNER 10000pF Fig. 2
TP1 : pin23 of IC101
TP2 : pin9 of IC101
TP5 TP3 : pin30 of IC101
5 0.1Vdc
DC POWER J156 TP5 : J156
SUPPLY
A GC
TP Noise
Level
Fig. 1 : Connection Diagram of Equipment for PIF Adjustment
(Before Adjustment) (After Adjustment)
* PIF (Picture Intermediate Frequency) Adjustment
1) Connect the Oscilloscope to the Main Board as shown
Test Point : TP1 in Fig. 2.
2) Set pattern generator as shown Table 2.
Adjust : VL101 3) Adjust VL102 so that the Noise level is minimized.
System Signal Pattern Sound signal Carrier signal
1) Connect the measuring equipment to the Main Board as
shown in Fig.1. SECAM-L Color bar Off On
2) Set RF frequency and output level of RF SIGNAL
GENERATOR as shown Table 1. (Table 2)
3) Turn on DC power supply.
4) Adjust VL101 so that the DC voltage may be indicated
2.6+_0.1Vdc.
* Vertical/Horizontal/E-W (East-West) EW--(Horizontal Width)
Adjust to that a digital circle pattern looks like exact circle.
Adjustment (LINE SVC 1)
EP--(East-west Parabola)
NOTE : These adjustments are already aligned at
Adjust so that middle portion of the outermost left and right
the time of manufacture for optimum
vertical line looks like parallel with vertical lines of the CPT.
performance. Readjustment of them
should not be necessary unless IC02
EC--(East-west Corner)
(EEPROM) is defective. Because all the
Adjust so that the vertical line at every 4 corners of the
information of these adjustment are
screen looks like parallel with the vertical lines of the CPT.
memorized in that IC.
ET--(East-west Trapezium)
Adjustment Procedures
Adjust to make the length of top horizontal line same with it
1) Tune the TV set to receive a digital circle pattern unless
of the bottom horizontal line.
otherwise noted.
2) Press OK button on Control Board continuously and OK
button on remote controller then you can find On
* White Balance Adjustment.(LINE SVC 2)
Screen Display. (Refer to the following Fig.3).
NOTE : This adjustment should be performed after screen
3) Press PR+ or PR- button for desirous function
voltage adjustment.
adjustment.
4) Press VOL+ or VOL- button for correct picture.
1) Tune the TV set to receive an 100% white pattern.
5) Press OK button to memorize all the adjusted data.
2) Press Number 2 button on remote controller in the SVC
6) After finishing adjustment, press TV/AV button on
Mode (press OK button on control board continuously
remote controller then TV is changed from SVC mode
and OK button on remote controller) then you can find
to normal mode.
On Screen Display. (Refer to the following Fig.4).
3) Press PSM (RED) button on remote controller. (Standard
[LINE SVC1] 1 picture)
CH5 4) Press PR+ or PR- button for desirous function
VL 43 EW 37
adjustment.
VA 21 EP 39 5) Adjust VOL+ or VOL- button for GG31.
SC 35 EC 29 6) Adjust VOL+ or VOL-button in each status of "RG--"/"BG--"
VS 35 ET 20 for X=288+_8, Y=295+_8 with color analyzer (color
HS 31 50HZ* temperature 9000oK).
[LINE SVC2] 1
CH5
*: This is only displayed according to
receiving system. RG31
GG31
PAL/SECAM System : 50Hz
[ NTSC System : 60Hz
BG23
DY12*
Fig. 3
Fig. 4
VL--(Vertical Linearity)
* : Never change this data, this is an important
Adjust so that the boundary line between upper and lower
reference data for TV.
half is in accord with geometric horizontal center of the CPT.
Ref) PAL I/I': DY15
VA--(Vertical Amplitude)
NOTE : If press Number 3 button on the remote controller
Adjust so that the circle of a digital circle pattern may be
in the SVC mode then you can find On Screen
located within the effective screen of the CPT.
Display. (Refer to the following Fig.5).
SC--(Vertical "S" correction)
Adjust so that all distance between each horizontal lines are [LINE SVC3] 1
to be the same. CH5
FP 30
VS--(Vertical Shift) NP 110
Adjust so that the horizontal center line of a digital circle SP 23
pattern is in accord with geometric horizontal center of the SV 75
CPT.
Fig. 5
HS--(Horizontal Shift)
Adjust so that the vertical center line of a digital circle pattern * Never change these data, these are important
is in accord with geometric vertical center of the CPT reference data for TV
* RF AGC (Automatic Gain Control) Adjustment * Focus Adjustment
NOTE: This adjustment should be performed after
Test Point : TP5 (J156) or Observing Display
warming up for 10 minutes.
Adjust : VR102
Test Point : Observing Display
The RF AGC control (VR102) was aligned at the time of Adjust : Focus control of FBT
manufacture for optimum performance over a wide range
conditions. Readjustment of VR102 should not be
necessary unless unusual local conditions exist, such as ; 1) Tune the TV set to receive an inactive channel station.
2) Adjust the Focus control of FBT for best overall focus.
1) Channel interference in a CATV system.
2) Picture bending and/or color beats, which are unusually
due to excessive RF signal input when the receiver is
too close to a transmitting tower or when the receiver
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.
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.
Adjusting the VR102(RF AGC) control to one end of
rotation will usually cause a relatively poor signal to noise
ratio;
Adjusting to the other end of rotation will usually cause a
degradation of over load capabilities resulting in color
beats or adjacent channel interference. For best results,
adjust the VR102 control while performing on all over local
channels, or the voltage at J156 will be 6.4◦ Jabse Service Manual Search 2024 ◦ Jabse Pravopis ◦ onTap.bg ◦ Other service manual resources online : Fixya ◦ eServiceinfo