Philips es1e, Руководство по обслуживанию

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Alignments EN 81 ES1E 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 Default Alignment Settings
Perform all electrical adjustments under the following
conditions:
•
Power supply voltage: 230 V
AC
/ 50 Hz ( r 10 %).
• 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: 100 : 1, Ri > 10 Mohm, Ci < 3.5 pF.
• Use an isolated trimmer/screwdriver to perform
alignments.
Perform all electrical adjustments with the following default
settings (for all CRTs):
•
Choose "Soft" picture mode with the "Smart Picture" button
on the remote control.
• Set "Dynamic Contrast" and "Active Control" to "off" (if
either one of them is present).
• Set "Brightness" to aligned value unless otherwise
specified.
• Set "Contrast value" to 99.
8.1.2 Adjustment Sequence
Use the following adjustment sequence:
1.
Set the correct TV-set OPTIONS as described in
paragraph "Options". After storing, re-start the set.
2. Rough adjustment of VG2 and FOCUS (potentiometers in
“midway” positions).
3. RF-AGC alignment.
4. IF-PLL OFFSET adjustment.
5. Rough adjustment of GEOMETRY.
6. Allow the set to warm up.
7. Precise adjustment of VG2 and FOCUS.
8. Precise adjustment of GEOMETRY.
9. PIP alignments (if present).
10. COLOUR alignments.
11. Other software alignments.
8.2 Hardware Alignments
Notes:
• The Service Alignment Mode (SAM) is described in chapter
5 "Service Modes, Error Codes, and Fault Finding".
• Use the cursor-, menu-, and OK-buttons of the remote
control (RC) transmitter for navigation.
Figure 8-1 Top view LSP
8.2.1 Vg2 Adjustment
In the frame-blanking period of the R, G, and B signals applied
to the CRT, the video processor inserts a measuring pulse with
different DC levels. Measure the black level pulse during the
vertical flyback at the RGB cathodes of the CRT.
1.
Connect the RF output of a pattern generator to the
antenna input. Input a "black" picture (blank screen on CRT
without any OSD info) test pattern.
2. In the SAM mode, set the “Normal Red”, “Normal Green”
and “Normal Blue” values to “0” for “White Tone”.
3. Disable the black current loop (via the AKB bit).
4. Use the MENU key to enter the "user" menu, select
"Picture", and set "Brightness" and "Contrast" to “0”.
5. Set the oscilloscope to 20 V/div and the time base to 20 us/
div. Use external triggering on the vertical pulse.
Caution : use a trigger point on the " cold " side!
6. Ground the scope on the CRT panel (" cold " side) and
connect a 10:1 probe to one of the cathodes of the picture
tube socket (see circuit diagram B1).
7. Measure at test points F338, F339 and F341 on the picture
tube socket the DC-level of the measuring pulse (1st full
line after the frame blanking) with respect to earth.
8. Select the pin with the highest level found and adjust
V_cutoff by means of the Vg2-potmeter (lowest-one) on the
Line Output Transformer (LOT) to 160 +/- 5 V
DC
(for all
screen sizes).
9. Reset "Contrast" and "Brightness" to their original values.
Figure 8-2 Waveform Vg2 alignment
CL 26532041_060.eps
110402
SSB
V.SHIFT CINCH SCART
TUNER
3642
1502
5430
Focus 2
Focus 1
Screen
VG2
LOT
Warning
All alignments
are on hot-part !
A
B
C
0V Re f .
CL 065 3 21 3 0 _ 014 .e p s
1 3 1000
V
CUTOFF
[V
DC
]
ma x .