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Fig.3: AFT waveform on Alignment Scope
● RF AGC (Auto Gain Control) Adjustment
Test Point :
J105(on Signal Board) / J22P
Adjust :
VR1T / VR1P
The RF AGC control (VR1T/ VR1P ) was aligned at the time of
manufacture for optimum performance over a wide range
conditions. Readjust of VR1T/ VR1P should not be necessary
unless unusual local conditions exist, such as:
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(60dBuV), the picture will be noise free in any area.
Adjusting the VR1T/ VR1P (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 reference.
For best results, adjust the VR1T/ VR1P control while
performing on all over local channels, or the voltage at J105/
J22P will be 5.6±0.2Vdc in RF level 60±2dBuV.
● High Voltage Stabilization Adjustment
Test Point :
TP1 (on Deflection Board)
Adjust :
VR422
1) Tune the TV set to receive a digital pattern.
2) Set contrast to 100%, brightness and color to 50%
respectively.
3) Adjust VR422 on the deflection board so that the DC
voltmeter may be read 4.0±0.2Vdc.
A: 36.8MHz
B: 38.0MHz
B
● Vertical/Horizontal Size Adjustment
Test Point :
Adjust :
1) Tune the TV set to receive a digital pattern.
2) Set contrast to 100%, brightness and color to 50%
respectively.
3) Adjust VR301 on the deflection board so that the circle of
the digital pattern may be located within the effective
screen on the TV screen.
4) Adjust VR404 on the deflection board so that the circle
of the digital pattern looks like exact circle.
● Horizontal center/SUB/SECAM Adjustment
NOTE : These adjustments are already aligned at the
time of manufacture for optimum performance.
Readjust of them should not be necessary
unless IC1 (EEPROM) is defective. Because all
the information of these adjustment are
memorized in that IC.
Adjustment procedures
1) Tune the TV set to receive a digital pattern unless
otherwise noted.
2) Press OK button on Control Board continuously and
SWAP(yellow) button on remote controller then you can
fine On Screen Display. (Refer to the following fig.4)
3) Press PR+ or PR- button for desirous function adjustment.
4) Press VOL+ or VOL- button for correct picture.
5) Press OK button to memorize all the adjusted data.
[ LINE
H-CENTER
SUB
SECAM
Horizontal center adjustment
Adjust so that the horizontal center line of digital pattern is in
accord with geometric horizontal center on the screen.
- 17 -
Observing Display
VR301 (Vertical Size)
VR404 (Horizontal Size)
SVC
1 ]
PR * *
15
BRIGHT
20
COLOR
10
TINT
10
BELL
05
R-Y
08
B-Y
14
AMP
02
Fig. 4
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