Philips EM1.1A, Руководство по обслуживанию

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Alignments EN 117 EM1.1A AA 8.
8. Alignments
Index of this chapter:
8.1 General Alignment Conditions
8.2 Hardware Alignments
8.3 Software Alignments
8.4 Option Settings
8.1 General Alignment Conditions
8.1.1 Start Conditions
Perform all electrical adjustments under the following
conditions:
•
AC voltage and frequency: according to country’s standard
• Connect the set to the mains via an isolation transformer
with low internal resistance.
• Allow the set to warm up for approximately 20 to 30
minutes.
• Measure voltages and waveforms in relation to chassis
ground (with the exception of the voltages on the primary
side of the power supply.)
Caution: never use heatsinks as ground.
• Test probe: Ri > 10 Mohm, Ci < 2.5 pF.
• Use an isolated trimmer/screwdriver to perform
alignments.
8.1.2 Start Settings
The following default settings are needed to start the
alignments:
•
Put the set in "Progressive Scan" mode (via "MENU -
PICTURE - DIGITAL OPTIONS".)
• Put the set in "MOVIES" mode (via the "PICTURE" button
on the remote transmitter.)
• Set "ACTIVE CONTROL" to "OFF" (via "MENU -
FEATURES".)
• Set "DYNAMIC CONTRAST" to "OFF" (via "MENU -
PICTURE".)
• Set the external video pattern generator to 475.25 MHz
(PAL/SECAM) or 61.25 MHz (NTSC).
8.1.3 Adjustment Sequence
Use the following adjustment sequence:
1.
Set the correct TV set ‘options’ (after storing, re-start the
set.)
2. Rough adjustment of ‘Vg2’ and ‘Focus.'
3. Rough adjustment of ‘Geometry.'
4. Allow the set to warm up.
5. Precise adjustment of ‘Vg2’ and ‘Focus.'
6. Precise adjustment of ‘Geometry.'
7. Software alignments.
8.2 Hardware Alignments
Note: The Service Default Mode (SDM) and Service Alignment
Mode (SAM) are described in the 'Service Modes, Error Codes
and Fault Finding' section. Menu navigation is performed with
the “MENU UP, DOWN, LEFT and RIGHT” keys of the remote
control (RC) transmitter.
Figure 8-1 Top view LSP
8.2.1 Vg2 Adjustment
Introduction
In the frame-blanking period of the R, G, and B signals applied
to the CRT, the 'HOP' video processor inserts a measuring
pulse with different DC levels. Measure this pulse during the
vertical flyback at the RGB cathodes of the CRT.
Alignment
1. Enter SAM. To enter SAM:
2. Press the following key sequence on the remote control
transmitter:
3. 0-6-2-5-9-6-STATUS/EXIT
4. Do not allow the display to time out between entries while
keying the sequence
5. Go to the 'WHITE TONE' sub menu.
6. Set the values of 'NORMAL RED,' 'NORMAL GREEN,' and
'NORMAL BLUE' to 32.
7. Go, via the "MENU" key, to the normal user menu and set:
–
"PICTURE" (CONTRAST) to zero.
– "BRIGHTNESS" to minimum (OSD just visible in a dark
room.)
8. Return to SAM via the "MENU" key.
9. Connect the RF output of a pattern generator to the
antenna input. Input a 'black' picture test pattern (blank
screen on CRT without any OSD info).
10. Set the oscilloscope to 50 V/div and the time base to 0.2 ms
(external triggering on the vertical pulse).
11. Ground the scope at the CRT panel and connect a 10:1
probe to one of the cathodes of the picture tube socket (see
diagram B).
12. Measure the 'cut off pulse' during the first full line after the
frame blanking (see Fig. 8-2). You will see two pulses; one
is the cut-off pulse and the other is the white drive pulse.
Choose the one with the lowest value; this is the cut-off
pulse.
13. Select the cathode with the highest VDC value for the
alignment. Adjust the VCUTOFF of this gun with the
SCREEN (lower) potentiometer (see Fig. 8-1) on the LOT
to the correct value:
–
29/ 32 /34 inch 16:9 CRT: 160 VDC
±
2 VDC.
– 36 inch 16:9 CRT: 165 VDC
±
2 VDC.
14. Restore "BRIGHTNESS" and "PICTURE" to normal values
(31).
CL 26532058_021.eps
0706402
SSB
V.SHIFT CINCH CINCH
TUNER
3642
1502
5430
Focus 2
Focus 1
Screen
VG2
LOT
Warning
All alignments
are on hot-part !
A
B
C