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Service Adjustments (Electronic Controls)
Note: Turn the Receiver ON. Operate the Receiver
for 60 minutes using the first Purity Check field
(white screen) to stabilize the CRT. Fully
degauss the Receiver by using an external
degaussing coil.
Sub-Brightness
Serviceman DAC Adjustment (B2)
Adjustment of this control is important for setting proper
operation of customer brightness and picture controls.
This adjustment must be made after Sub-Contrast or
Color Temperature adjustments are made. Do not
adjust the SCREEN VR after the Sub-Brightness
is set.
Preparation:
3.
Preset the following controls:
• Tint. . . . . . . . . . . . . .Center.
• Color . . . . . . . . . . . . Center.
• Picture . . . . . . . . . . . Max.
4.
Apply a Black and White cross pattern.
5.
Operate the Receiver for a minimum of 30 minutes
prior to performing this adjustment.
Procedure:
In the Serviceman Mode for making electronic
adjustments, select the DAC adjustment (B2) and
adjust until the 7.5 IRE part is the same light output
as 3 IRE part.
You may set the accurate value following the
Preparation steps and the Procedure step No. 1 of the
Sub-Contrast adjustment described below.
Sub-Contrast
Serviceman DAC Adjustment (B3)
This adjustment is factory set. Do not adjust unless
repairs are made to associated circuit, the CRT Board
or when the CRT is replaced.
Preparation:
1.
Apply a color bar signal pattern with 87.5%
modulation, 70% saturated color bar with a 100
IRE white and 7.5 black.
Note:
The pattern used in this procedure is an EIA color
bar pattern with 87.5% modulation with 100 IRE
white and 7.5 black. Correlate the information in this
procedure to the pattern used if another signal
is used.
2.
Preset the following controls:
• Brightness . . . . . . . .Center.
• Color . . . . . . . . . . . .Min.
• Picture . . . . . . . . . . . Max.
• Sharpness . . . . . . . . Center.
3.
Set RGB Gamma Register OFF (S3 to 0)
4.
Connect the oscilloscope to TP47R (A-Board,
below IC101).
5.
Set the scope time base to 20
µ
s (horizontal).
6.
Connect a jumper from TPD2 to ground (
).
Procedure:
1.
In the Serviceman Mode, select DAC
Sub-Brightness Adjustment (B2) and adjust for
1.5~1.9Vp-p between blanking and 7.5 IRE level.
2.
In the Serviceman Mode for electronic
adjustments, select DAC Sub-Contrast Adjustment
(B3) and adjust for 1.5Vp-p ± 0.1V from white level
to black level on video waveform (see video
waveforms detail, Fig. 23).
3.
Remove the jumpers (Preparation step 6).
4.
Set S3 to 1.
Tint/Color Adjustment
Serviceman DAC Adjustment (B1) (B0)
Preparation:
1.
Preset the following controls:)
• Tint. . . . . . . . . . . . . . . . . . . . Center.
• Color . . . . . . . . . . . . . . . . . . Center.
• Picture . . . . . . . . . . . . . . . . . Max.
• Sharpness . . . . . . . . . . . . . . Min.
• Bright . . . . . . . . . . . . . . . . . . Min.
• Color Temp . . . . . . . . . . . . . Normal.
2.
Set RGB Gamma Register OFF (S3 to 0).
3.
Connect a jumper from TPD2 to ground (
).
7.5 IRE
3 IRE
7.5 IRE
3 IRE
Figure 22. Sub-Bright Pre adjustment
Figure 23. TP47R waveform
1.5V
p-p
±0.1V
White
Yellow
Cyan
Green
Magenta
Red
Blue
Black
SYNC
TIP
1.5V
p-p
~ 1.9V
