Panasonic CT-27D10UB Service-Handbuch - Seite 24

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Service Adjustments (Electronic Controls)

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 SCREEN after the Sub-Brightness is set.

Preparation:

Apply a color bar signal wit 100 IRE white and 7.5

IRE black. (Switch Color to "OFF" on the signal

generator.) Operate the Receiver for a minimum of

10 minutes prior to performing this adjustment.

Procedure:

In the Serviceman Mode for making electronic

adjustments, select the DAC adjustment (B2) and

adjust until the black starts to look gray. Then

decrease the level to the point where gray turns

to black.

Note:

You may set the accurate value following the

Preparation steps and the Procedure step No.

2 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. Connect the oscilloscope to TP47R. Set the scope

time base to 20µs (horizontal).

4. Connect a jumper from TPD2 to ground (

White

Yellow

Cyan

2.0V

±0.1V

p-p

1.5V - 1.9V

p-p

Figure 19. TP47G waveform

)..

Green

Magenta

Red

Blue

Black

SYNC

TIP

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. (See

video waveforms detail, Fig. 19)

2. In

the

Serviceman

adjustments, select DAC Sub-Contrast Adjustment

(B3) and adjust for 2.0Vp-p ±0.1V white level to

black level on video waveform (see video

waveforms detail, Fig. 19).

3. Remove the jumper (Preparation step 4).

Tint/Color Adjustment

Serviceman DAC Adjustment (B1) (B0)

Preparation:

1. Apply a rainbow color bar signal.

2. Preset the following controls:

• Brightness . . . . . . . Min.

• Color . . . . . . . . . . . . Center.

• Tint . . . . . . . . . . . . . Center.

• Picture . . . . . . . . . . Max.

• Sharpness . . . . . . . Min.

3. Connect the oscilloscope to TP47B (A-Board).

4. Connect a jumper from TPD2 to GND (

5. Change the value of DAC S3 from 1 to 0.

Procedure:

1. In the Serviceman Mode for making electronic

adjustments, select DAC Sub-Tint Adjustment

(B1). Adjust until the waveform measured is as the

one shown in Fig. 20.

TP47B (A-Board)

A to B = 1 unit

B to C = 2 units

Figure 20. TP47B waveform

2. Connect the oscilloscope to TP47G (A-Board).

3. Select DAC Sub-Color Adjustment (B0) and adjust

for peak to peak amplitude to be 0.65Vp-p ±0.05V

for 27" models as shown in Fig. 21.

TP47G (A-Board)

1 2 3 4 5 6

Figure 21. TP47G waveform

4. Remove the jumpers (Preparation steps 4 & 5).

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Mode

for

electronic

1 2 3

4 5 6 7 8 9

0.65Vp-p±0.05V

7 8 9 10