Electrical Alignments
EN 86
8.
Figure 8-2 Waveform Vg2 alignment
8.2.2
Focus alignment
The LOT has the following outline:
–
Focus 1 (F1) = Static alignment (black wire).
–
Focus 2 (F2) = Dynamic alignment (red wire).
1.
Use an external video pattern generator to input a "circle"
or "crosshatch" test pattern to the set.
2.
Choose "Natural" picture mode with the "Smart Picture"
button on the remote control transmitter.
3.
Adjust the "dynamic focus 2" potentiometer (in the middle
on the LOT) until the horizontal lines at the centre of the
screen are of minimum width without introducing a visible
haze.
4.
Adjust the "static focus 1" potentiometer (highest of the
LOT) until the horizontal lines at the sides of the screen are
of minimum width without introducing a visible haze.
5.
Repeat these two steps to achieve the best result.
8.3
Software Alignments
Put the set in the SAM (see the "Service Modes, Error Codes
and Fault Finding" section). The SAM menu will now appear on
the screen. The different alignment parameters are described
further on.
Notes:
•
All changes to menu items and alignments must be stored
manually.
•
If an empty EAROM (permanent memory) is detected, all
settings are set to pre-programmed default values, so the
set must be re-aligned.
8.3.1
TUNER
AGC
1.
Set an external pattern generator to a colour bar video
signal and connect the RF output to the aerial input of the
TV. Set the amplitude to 10 mV and the frequency to
475.25 MHz. Use system PAL B/G if possible, otherwise
match the system of your generator with the received
signal in the set.
2.
Put the set in the SAM mode.
3.
Select via the TUNER menu, the AGC sub-menu.
4.
Connect a DC multi-meter to pin 1 of the tuner (item 1200
on the LSP).
5.
Adjust the AGC until the voltage at pin 1 of the tuner is 3.3
V (+/- 0.1 V). The value can be incremented or
decremented by pressing the right/left CURSOR button on
the RC.
6.
After alignment, save the value(s) with the STORE
command in the SAM main menu.
IF PLL OFFSET
No adjustments needed: default value is "35".
If the mentioned default value does not give the required result,
use the following alignment method:
1.
Set an external pattern generator to a crosshatch video
signal and connect the RF output to the aerial input of the
TV. Set the amplitude to 10 mV and the frequency to
475.25 MHz. Use system PAL B/G if possible, otherwise
match the system of your generator with the received
signal in the set.
–
For "Negative modulation", the sound signal must be
a non-modulated FM signal.
–
For "Positive modulation", the video signal must have
high modulation (100% or above).
2.
Put the set in the SAM mode.
3.
Select via the TUNER menu, the IF-PLL OFFSET sub-
menu.
4.
Measure and align:
–
For "Negative modulation", on SCART pin 1 or 3
(audio out): Adjust IF-PLL OFFSET until the largest
Signal Noise Ratio (SNR) is reached.
–
For "Positive modulation", on SCART pin 19 (video
out): Adjust IF-PLL OFFSET until you get minimal V-
sync disturbance.
8.3.2
GEOMETRY
Notes:
•
Set an external pattern generator to a crosshatch video
signal and connect the RF output to the aerial input of the
TV. Set the amplitude at least 1 mV_rms (60 dBuV) and the
frequency to 475.25 MHz. Use system PAL B/G if possible,
otherwise match the system of your generator with the
received signal in the set.
Note: Do not use the internal test pattern from the
GEOMETRY menu!
•
Use the default alignment settings, but set "Brightness" to
"32".
•
For wide screen models, set to "wide screen" mode, for
"classic" models, set to "4:3".
•
After alignment, save the value(s) with the STORE
command in the SAM main menu.
Service tip: When the set is equipped with a rotation coil, use
this menu item to check its correct alignment. If alignment is not
correct, go to the user MENU, choose FEATURES, and select
ROTATION. With the use of a crosshatch test pattern, align it
to a correct horizontal picture.
0V Ref.
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