SONY KDL-32XBR950, KDL-42XBR950 Service Manual

Televisions

Theory of Operation and Troubleshooting

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Flowchart A

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Video Distortion Troubleshooting Flowchart

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Flowchart A

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Video Distortion Troubleshooting Flowchart

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XBR950 Troubleshooting Flow-

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Flowchart A

Troubleshootin

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Video Troubleshooting Flowchart

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Audio Troubleshooting Flowchart

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Chapter 1 - Basic LCD Display Theory

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Chapter 2 - LCD Display Troubleshooting

Video Abnormalities Troubleshooting

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White Balance

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Adjusting White Balance

Adjusting White Balance Without a Color Analyzer

Table of Contents

Appendix

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Video Processing

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Audio Processing

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Video Processing

Audio Processing

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Audio Processing

With this concept in mind the sequence of this training manual is laid out

providing the basic explanations

from this information will prove to be extremely helpful in understanding

why and how possible defects can occur.

is a natural extension of chapter 1, in that it provides

provide model speciﬁ c ﬂ owchart type troubleshooting

Chapter 1 - Basic LCD Display Theory

wires normally found in front projection setups. Advances in screen design

video with improved viewing angles that rivals front projection devices.

LCD display units. The video

follow will focus on them.

front, allowing only horizontal phased light to pass, the light is effectively

1. Basic LCD Television

Although liquid crystals come in many different forms, the key difference

ﬁ elds, and electrical current. The crystals used in LCD display devices

fully “un-twist” the crystals. The polarized backlight is now perpendicular to

VOLTAGE EFFECT ON LIQUID CRYSTALS

1. Basic LCD Television

All that is required for LCD pixels to create color is to place a color ﬁ lter in

front of each pixel. By using red, green, and blue color ﬁ lters, the required

what is known as Thin-Film Transistor (TFT) technology. Each pixel has

1. Basic LCD Television

full passage of the backlighting is allowed. Control of the light output from

Chapter 2 - LCD Display Troubleshooting

will be given to the circuits that control and drive the panel. The Key

will have been scaled to meet the ﬁ xed resolution of the panel. This digital

that are usually seen when the video process circuits are at fault.

this manual will contain troubleshooting ﬂ owcharts speciﬁ cally tailored for

followed with troubleshooting ﬂ owcharts speciﬁ c to them. This manual will

2. LCD Television Troubleshooting

Video abnormalities can be anything from no video at all, missing lines

A true “no video” condition assumes that none of the various inputs or

All LCD televisions, whether a direct-view or projection type, require a

viewer. In direct-view units the current choice is multiple ﬂ uorescent tube

turned off to see if the raster becomes slightly darker.

All Sony LCD televisions contain protection circuits to monitor the circuits

the unit will usually shut down and display a diagnostics indication. How

this is done is unique to each model. Utilizing a troubleshooting ﬂ owchart

for that speciﬁ c model is the best way to isolate the cause. Veriﬁ cation

functioning. The focus of attention is now in the video input and process

2. LCD Television Troubleshooting

very expensive and specialized equipment is needed to repair the bond.

Any unit under warranty will need to have the panel replaced. Figure 2-1

2. LCD Television Troubleshooting

for processing video are the initial circuits to perform analog to digital

2. LCD Television Troubleshooting

Video level issues can affect one or all of the primary colors. The panel

failure in the initial video stages. It is not likely that a failure in the gamma

White balance issues with a projection LCD unit are approached in an

white balance shift towards the particular color of the panel that lost drive.

White balance adjustments are provided to vary the output level of the red,

Warm.

Adjusting of white balance is only required if the unit has had a board

the unit through time, or when someone else has changed the settings.

Adjusting White Balance

to perform this adjustment varies from model to model. It also varies

what color temperature to start with. Some direct-view LCD models have

for reading color balance from the screen also varies for a projection or

2. LCD Television Troubleshooting

Adjusting White Balance Without a Color Analyzer

When adjusting an LCD display, there are no cutoff adjustments. In this

white balance towards the red end of the scale whereas the “Cool” setting

the Blue and Red data to achieve white by adding these colors to the

4. Set the Blue upper-bit and lower-bit data for Sub-Contrast and

the brightest portion of the test pattern. If you ﬁ nd that you are

the above procedure for the Red Sub-brightness adjustments.

to white. If you are at either of the extreme ends of the data ranges

white balance in the same way. Add a small amount of extra Red

Although the above procedure can be somewhat subjective, it has worked

2. LCD Television Troubleshooting

viable alternative when a color analyzer is impossible to acquire.

KLV-26HG2 Index Troubleshooting

Flowchart A

Start

Initial Analysis

Does unit

Turn ON?

Is Video

Present

Yes

Is Video

Distorted

Is Audio

Present

Is RED LED

Flashing?

Yes

Red LED ON in Standby

Green LED flashes and

Glows Steady

GO TO

Power

-ON

Troubleshooting

Flowchart B

GO TO

Protection Mode Troubleshooting

Flowchart C

1, 2, 3

GO TO

No Video

Troubleshooting

Flowchart D

GO TO

Video Distortion

Troubleshooting

Flowchart E

GO TO

No Audio

Troubleshooting

Flowchart F

GO HOME

No Problem

Found

Unit Fully

Operational

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