Philips 28PW9618, Service Manual

Page: 122 / 172

Electrical Alignments
EN 122 EM6E 8.
8.3
Software Alignments
With these alignments, it is possible to align the Geometry,
White Tone, and Tuner IF settings.
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. Select ALIGNMENTS and go to one of the sub
menus. All these alignments are explained below.
Notes:
•
All changes to menu items and alignments are stored
automatically, except changes to the option codes. They
must be stored manually.
•
If an empty EAROM (permanent memory) is detected, all
settings are set to pre-programmed default values.
8.3.1
GENERAL
VG2 TEST PATTERN
In this sub menu, you can turn "on" the OSD feedback for the
Vg2 alignment (see "Vg2 Adjustment" section).
ADJUST PEAK WHITE LIMITER
Fixed setting of "9".
EHT COMPENSATION
Fixed setting of "0".
SOFT CLIPPER
Fixed setting of "Pwl + 0%".
LUMA GAIN
Fixed setting of "2".
DELTA LUMA GAIN FOR AUX
Fixed setting of "0 dB".
IF AFC
Supply, via a service generator or via off-air, a TV-signal with a
signal strength of at least 1 mV and a frequency of 475.25 MHz.
Alignment procedure:
1.
During the IF AFC-parameter adjustment, one can see
OSD feedback on the screen.
2.
The OSD feedback can give 4 kinds of messages:
3.
The first item (IN/OUT) informs you whether you are in or
out of the AFC-window.
4.
The second item (HIGH/LOW) informs you whether the
AFC-frequency is too high or too low.
Table 8-3 OSD feedback of AFC alignment
1.
Adjust the IF AFC parameter until the first value is within
the AFC window (= IN).
2.
Next, adjust the IF AFC parameter until the second value
is LOW.
IF LPRIME AFC
Same procedure as described above but with other signal
source (SECAM L').
TUNER AGC
1.
Connect the RF output of a video pattern generator to the
antenna input.
2.
From the generator, input a PAL B/G TV signal with a
signal strength of approximately 2 mV and a frequency of
475.25 MHz.
3.
Measure the DC voltage on pin 1 of the (main) Tuner. You
can adjust this voltage by adjusting the TUNER AGC item
in the SAM menu. Alignment is correct when the DC
voltage is just below 3.5 V.
IF AFC TUNER 2
Use the same procedure as described above (under IF AFC)
with the set switched to the DW source.
IF LPRIME AFC TUNER 2
Use the same procedure as described above (under IF
LPRIME AFC) with the set switched to the DW source.
TUNER AGC TUNER 2
Use the same procedure as described above (under TUNER
AGC) with the set switched to the DW source. Measure on pin
1 of the DW Tuner.
BLEND INTENSITY
Use this alignment when you replace the microcontroller or the
HOP. It aligns the level of transparency of the menu-picture
blended into the main-picture.
Position the "Brightness", "Contrast", and "Colour" setting in
the middle position (in the customer "Picture" menu).
1.
Apply a signal with a 100 % white video pattern (white
raster).
2.
Connect an oscilloscope to pin 8 of connector 1298 of the
CRT panel and measure the Red output level.
3.
Align the BLEND INTENSITY parameter so that the
blended signal is 65 % of the black-white amplitude. This
will be about 1.3 V (blended signal) versus 2 V (full white
signal).
4.
The parameter can be adjusted from 0 to 31.
8.3.2
DRIVE (Colour Alignments)
Note: Switch off all (available) colour-influencing features (set
the TV in ECO-mode).
Method 1 (with colour analyser):
1.
Set, via the user menu, the "Contrast" to "100".
2.
In SAM, select TEST PATTERN and turn it ON. During the
following alignments, you will see a white block in the
middle of the screen. Measure with the colour analyser on
this area.
3.
Set, via the user menu, the "Brightness" to a value between
3.0 and 5.0 Nit (rough setting).
4.
in SAM, select CATHODE and adjust the set to the correct
light output. This setting depends on the picture tube size
and brand. See "Cathode parameter" table for the colour
analyser readings.
5.
Select a COLOR TEMPERATURE (e.g. COOL, NORMAL,
or WARM).
6.
Adjust the white level, via RED, GREEN, and BLUE,
according to the values in table "White levels".
Table 8-4 Cathode parameter
AFC-window AFC-frequency vs. reference
Out High
In High
* In * * Low *
Out Low
CRT size Light output (cd/m2)
28 inch RF WS (Mk II) 450
32 inch RF WS (EMEC) 395
36 inch RF WS (EMEC) 345