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Alignments
8. Alignments
General: the Service Default Mode (SDM) and Service
Alignment Mode (SAM) are described in chapter 5 'Service
modes, faultfinding and repair tips'.
8.1
Alignment conditions
All electrical adjustments should be performed under the
following conditions:
•
Supply voltage : 220 - 240 VAC (+/- 10 %)
•
Warm-up time: 10 minutes
•
The voltages and oscillograms are measured in relation to
the tuner earth (with exception to the voltages on the
primary side of the power supply). Never use the cooling
fins/plates as earth.
•
Test probe: Ri > 10MΩ Ci < 2,5 pF.
8.1.1
Selection of the SAM-menu
•
By transmitting the "ALIGN" command with the RC7150
Dealer Service Tool, followed by password "3140" and <
OK > button.
•
By shorting SAM pin on the AV Control panel at the rear of
the monitor while switching on the set.
8.2
Electrical Alignments
8.2.1
Adjustments on the DW panel
VCO alignment (L9H0)
•
Connect a signal generator (e.g. PM5326) to the tuner of
the set.
•
Select a 475.25 MHz colour bar without sound.
•
Set the subchannel frequency 475.25 MHz in the DW
mode.
•
Connect an oscilloscope to TP15 and adjust L9H0 for a DC
level of 2,5V +/- 0.1V.
AGC take over point adjustment (R9G5)
Introduction
The AGC adjustment prevents overdriving of the PIP-tuner if
the aerial signal is too strong. Overdriving is visible as a loss of
colour and synchronisation in the PIP picture. Amplification has
to be adjusted to minimum level, but the PIP-picture should be
as free of noise as possible.
Adjustment
•
Connect a signal generator to (e.g. PM5326) to the tuner of
the set.
•
Select a 475.25 MHz colour bar without sound.
•
Set the subchannel frequency 475.25 MHz in the DW
mode.
•
Connect an oscilloscope to TP14 and adjust R9G5 for a
DC level of 3,5 V +/- 0.1 V.
Phase alignment (R9G6)
•
Connect a signal generator to (e.g. PM5326) to the tuner of
the set.
•
Select a 475.25 MHz window signal (centre white) without
sound.
•
Set the subchannel frequency 475.25 MHz in the DW
mode.
•
Connect an oscilloscope to TP20 and adjust R9G6 that the
shape of horizontal white black jump becomes as figure
below
FTV1.9EE
1 Offset = 4.5uA
Figure 8-1
M-trap alignment (L9G0)
•
Connect a signal generator to (e.g. PM5326) to the tuner of
the set.
•
Select a 475.25 MHz colour bar with 4.5 MHz sound
carrier.
•
Set the subchannel frequency 475.25 MHz in the DW
mode.
•
Connect an oscilloscope to TP20 and adjust L9G0 to
minimum amplitude of 4.5 MHz sine wave on the sync-
chip.
8.2.2
CVBS level adjustment on the Small Signal Panel
For this alignment it is necessary that the comb filter (module),
DW module and feature box are in the SSP.
For sets without PAL plus feature.
Input signal : Antenna test signal PAL 75% colourbar
Measure Y-FEAT on pin 1 of connector S48 and align R3361
[S5] until the amplitude = 1.0V
For sets with PAL plus.
Input signal : Antenna test signal PAL 75% colourbar
Set TDA9143/44 in PAL plus mode ( HW option code nr 3 - bit
7 )
Measure Y-MAC on pin 2 of connector S62 or pin 2 of
connector S49 and align R3361 [S5] until the amplitude =
1.1V
5%
black-white
8.
GB 75
1 Offset = 0uA
CL 66532066_001.ai
221096
5%.
black-white
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