SAMSUNG CT26F7SWX-XAP Service Manual

COLOR TELEVISION RECEIVER

Chassis : K15C Model : CT26F7SWX/XAP

COLOR TELEVISION RECEIVER CONTENTS

Precautions

Specifications and IC Data

Disassembly and Reassembly

Alignment and Adjustment

Troubleshooting

Exploded View and Parts List

Electrical Parts List

Block Diagram

Wiring Diagram

Schematic Diagrams

10.

ELECTRONICS

Printed in Korea

AA82-00088A

Alignment and Adjustments

Samsung Electronics 4-1

4. Alignment and Adjustments

4-1 Preadjustment

4-1-1 Factory Mode

1. Do not attempt these adjustments in the Video Mode.

2. The Factory Mode adjustments are necessary when either the EEPROM (IC902) or the CRT is replaced.

3. Do not tamper with the “Adjustment” screen of the Factory Mode menu. This screen is intended only for factory use.

4-1-2 When EEPROM (IC902) Is Replaced

1. When IC902 is replaced all adjustment data revert to initial values. It is necessary to re-program this data.

2. After IC902 is replaced, warm up the TV for 10 seconds.

4-1-3 When CRT Is Replaced

1. Make the following adjustments AFTER setting up after setting up purity and convergence :

White Balance Sub-Brightness Vertical Center Vertical Size Horizontal Size Fail Safe (This adjustment must be the last step).

2. If the EEPROM or CRT is replaced and set SC as 35(factory mode).

4-2 Factory/Service Mode

4-2-1 Procedure for the “Adjustment” Mode

1. This mode uses the standard remote control. The Service Mode is activated by entering the following remote-control sequence :

(1) DISPLAY → FACTORY.

(2) STAND-BY → MUTE → 1 → 8 → 2

→POWER ON.

2. The “SERVICE (FACTORY)” message will be displayed. The Service Mode has four components: ADJUST, OPTION , G2-ADJUST and RESET.

3. Access the Adjustment Mode by pressing the “VOLUME” keys ( Up or Down). The adjustment parameters are listed in the accompanying table, and selected by pressing the CHANNEL keys ( , ).

4. Selection sequences for the all system:

DOWN or UP key:

SCT>SBT>BLR>BLB>RG>GG>BG>VSL>VS> VA>HS>SC>CDL>STT>AKB>PDL>NDL> PSR>NSR>SCBT>VOL>CAP>MVOL>RP00> RP01>FMWS>AGC1>OMD>SCL>PWL> MUS>AGC>DSK>DVDB

5. The VOLUME keys increase or decrease the adjustment values (stored in the non-volatile memory) when Adjustment Mode is cancelled.

6. Cancel the Adjustment Mode by re-pressing the “FACTORY” or “Power OFF” keys.

4-2-2 Main Adjustment Parameter

Alignment and Adjustments

4-2 Samsung Electronics

ONO SD F U N CT I ON R AN G E I NI TI AL D AT A SETTING RE MARK

SCT Sub Cont ras t 0 ~ 23

SBT Sub Bright nes s

SCBT Screen Brighrtness 0 ~ 63

MVOL

RP00

RP01

FMWS

AGC1

OMD

Black Level offset Red

BLR

Black Level offset Blue

BLB

RG Red Gain 0~63

GG Green Gai n 0 ~ 63

BG Bl ue Gai n 0 ~ 63

VSL Ver t ical Slope 0 ~ 63

VS Ver t i cal Sh if t 0 ~ 63

VA Vert ical Ampli tud e 0 ~ 63

HS Horizontal Shif t 0 ~ 63

SC S- Cor r ec t i on 0 ~ 63

CDL Cathode Drive Level 0 ~ 15

STT Sub Tint 0 ~ 7

AKB AKB On / off 0 ~ 1

PDL P AL De l a y 0 ~ 1 5

NDL NTSC Delay 0 ~ 15

PSR PAL Sub color 0 ~ 23

NSR NTSC Sub color 0 ~ 23

VOL Volume pre set t i ng 0 ~ 63

CAP Caption Position

Melody Sound Volume

Ratio Pre / overshoot

Window Selection Sound PLL

IF AGC Speed

Offset IF Demodulator

SCL

Soft Clipping Level

PWL

Peak White Limitting

MUS

Matrix USA

AGC

Automatic Gain Control

DSK

Dynamic Skin Tone

DVDB

DVD Bright Offset

0~23

0~63

0~15

0~50

0~1

0~3

0~63

0~3

0~15

0~1

0~63

0~1

00~1

(16)

(6)

(37)

(33)

(38)

(39)

(32)

(20)

(33)

W/B Adjustment

FIX

W/B Adjustment

Vertical Picture Adjusment

FIX

Vertical Picture Adjusment

Picture Adjusment

FIX

FIX (Mono)

FIX (Nomal)

FIX (No Crrection)

FIX (Off)

FIX (100%)

FIX (Mono)

FIX

Alignment and Adjustments

Samsung Electronics 4-3

4-2-3 Option Bytes

In the Service Mode, various can be selected via the Option Table. Example:

Option Table : xx xx

OSD

VIDEO MUTE

AUDIO

E/W

ZOOM

AUTO POWER

AUDIO MUTE

LANGUAGE

HOTEL MODE

BULE SCREEN

2'nd SIF

V-CHIP

SETTING

OFF

STEREO

OFF

NOR/ZOOM

OFF

ENGLISH

OFF

INTERNAL

REMARK

- Video Mute On/Off changing the channel

- Audio Option (Mono / Steeo)

- E/W Option

- Picture Size Option

- Master S/w Option

- Audio Mute On/ Off without signal

- Inital Language agter Factory Reset

- Hotel mode On/ Off

- Bule Screen On/ Off without signal

- SIF Option at Mono sound

- V-CHIP On/Off

AV Option

DEMO

AV + DVD

OFF

- DVD, S-VHS Option

- DEMONSTRATION On/Off

Alignment and Adjustments

4-4 Samsung Electronics

4-3 Other Adjustments

4-3-1 General

1. Usually, a color TV needs only slight touchup adjustment upon installation. Check the basic characteristics such as height, horizontal and vertical sync and focus.

2. The picture should have good black and white details. There should be no objectionable color shading; if color shading is present, perform the purity and convergence adjustments described below.

3. Use the specified test equipment or its equivalent.

4. Correct impedance matching is essential.

5. Avoid overload. Excessive signal from a sweep generator might overload the front-end of the TV. When inserting signal markers, do not allow the marker generator to distort test results.

6. Connect the TV only to an AC power source with voltage and frequency as specified on the backcover nameplate.

7. Do not attempt to connect or disconnect any wires while the TV is turned on. Make sure that the power cord is disconnected before replacing any parts.

8. To protect against shock hazard, use an isolation transformer.

4-3-2 Automatic Degaussing

A degaussing coil is mounted around the picture tube, so that external degaussing after moving the TV should be unnecessary. But the receiver must be properly degaussed upon installation.

The degaussing coil operates for about 1 second after the power is switched ON. If the set has been moved or turned in a different direction, disconnect its AC power for at least 30 minutes.

If the chassis or parts of the cabinet become magnetized, poor color purity will result. If this happens, use an external degaussing coil. Slowly move the degaussing coil around the faceplate of the picture tube and the sides and front of the receiver. Slowly withdraw the coil to a distance of about 6 feet before removing power.

4-2-4 RESET

The Reset Mode is used during factory inspection. Function Reset:

1. Picture Mode Custom

2. Sound Mode Custom

3. Auto Volume Off

4. Melody On

5. Surround Off

6. Turbo Sound Off

7. MTS Stereo

8. Language English

9. Caption Off

10. Timer Off

Alignment and Adjustments

Samsung Electronics 4-5

4-3-3 High Voltage Check

CAUTION: There is no high voltage adjustment on this chassis. The B+ power supply must be set to +125 volts (Full color bar input and normal picture level).

1. Connect a digital voltmeter to the second

anode of the picture tube.

2. Turn on the TV. Set the Brightness and

Contrast controls to minimum (zero beam current).

3. The high voltage should not exceed 30KV.

4. Adjust the Brightness and contrast controls to

both extremes. Ensure that the high voltage does not exceed 30KV under any conditions.

4-3-4 FOCUS Adjustment

1. Input a black and white signal.

2. Adjust the tuning control for the clearest pic-

ture.

3. Adjust the FOCUS control for well defined

scanning lines in the center area of the screen.

4-3-5 Cathode Voltage Adjustment

(Screen Adjustment)

1. Connect CRT socket pin GK to an oscilloscope

probe.

2. Input a gray scale pattern. (Use a pattern gen-

erator, PM5518)

3. Use the P mode key (on the remote control)

for the STANDARD picture.

4. Adjust the Screen VR (on the FBT) so that the

voltage on the oscilloscope becomes 125+2.5V (See Fig. 4-1).

4-3-6 Purity Adjustment

1. Warm up the receiver for at least 20 minutes.

2. Plug in the CRT deflection yoke and tighten the clamp screw.

3. Plug the convergence yoke into the CRT and set in as shown in Fig. 4-2.

4. Input a black and white signal.

5. Fully demagnetize the receiver by applying an external degaussing coil.

6. Turn the CONTRAST and BRIGHTNESS controls to maximum.

7. Loosen the clamp screw holding the yoke. Slide the yoke backward or forward to provide vertical green belt. (Fig. 4-3).

8. Tighten the convergence yoke.

9. Slowly move the deflection yoke forward, and adjust for the best overall green screen.

10. Temporarily tighten the deflection yoke.

11. Produce blue and red rasters by adjusting the low-light controls. Check for good purity in each field.

12. Tighten the deflection yoke.

Fig. 4-1

125 2.5V

GND

Alignment and Adjustments

4-6 Samsung Electronics

4-3-7 White Balance Adjustment

Fig. 4-2 Convergence Magnet Assembly

Fig. 4-3 Center Convergence Adjustment

Fig. 4-4

(a) Set up

1. Warm up the TV for at least 30 minutes in the Aging Mode (OSD White). This mode is displayed by entering the following sequence:

DISPLAY

→FACTORY → FACTORY

2. Input a Toshiba pattern.

(b) Low-Light Adjustment

1. Set SBT to 1.0 fL in the Factory Service Mode with using CA100. See Fig. 4-4.

2. Adjust RG,BG so that the levels are suitable to each local area.

1. Set SCT to 35 FL in the Factory Service Mode with using CA100. See Fig. 4-4 .

6 Pole Magnet

Clamper

Screw

4 Pole Magnet

2 Pole Magnet

2 POLE PURITY

4 POLE CONVERGENCE

Vertical Green Belt

YOKE CLAMP SCREW

6 POLE CONVERGENCE

ADJ (VE

31m/m

Alignment and Adjustments

Samsung Electronics 4-7

4-3-8 Center Convergence Adjustment

1. Warm up the receiver for at least 20 minutes.

2. Adjust the two tabs of the 4 pole magnets to change the angle between them. Superimpose the red and blue vertical lines in the center area of the screen.

3. Adjust the Brightness and Contrast controls for a well defined picture.

4. Adjust the two-tab pairs of the 4 pole magnets, and change the angle between them. Superimpose the red and the blue vertical lines in the center area of the screen.

5. Turn the both tabs at the same time, keeping the angle constant, and superimpose the red and blue horizontal line in the center of the screen.

6. Adjust the two-tab pairs of the 6-pole magnets to superimpose the red and blue line onto the green. (Changing the angle affects the vertical lines, and rotating both magnets affects the horizontal lines.)

7. Repeat adjustments 2~6, if necessary.

8. Since the 4-pole magnets and 6-pole magnets

interact, the dot movement is complex (Fig. 4-5).

Fig. 4-5 Center Convergence Adjustment

BLUE

RED

RED/BLUE

GREEN

4-Pole Magnet Movement

6-Pole Magnet Movement

4-3-9 RF AGC Adjustment

Set the AGC data to 33 (Factory Mode).

4-3-10 Sub-Color Adjustment

Set data to (Factory Mode).

4-3-11 Geometry Adjustment

SC →VS→VA→VSL→HS

1. Input a lion head pattern.

2. Set the SC (S-Correction) as 35 and VS(Vertical Shift) 31 so that the lion head circle becomes oval.

3. Adjust with VA (Vertical Amplitude) so that the top margin of the picture is 4.

Fig. 4-7

4. Adjust with VSL (Vertical-Slope) so that the bottom margin of the picture is 4.

Fig. 4-8

5. Adjust with HS (Horizontal Shift) so that the lion-head pattern and CRT centers are aligned.

Fig. 4-9

6. Adjust HS (Horizontal Shift) so that the left and right margins of the picture are 5.

Alignment and Adjustments

4-8 Samsung Electronics

PSR NSR

Disassembly and reassembly

Samsung Electronics 3-1

3. Disassembly and Reassembly

3-1 Back Cover Removal

1. After removing the screws, press the tension rib and pull the cabinet backwards.

2. To reassemble, press the tension rib (see diagram).

Disassembly and reassembly

3-2 Samsung Electronics

3-2 Main Board Removal

3-3 Speaker Removal

1. Separate the socket board from the CRT neck.

2. Remove the Anode Cap from the CRT.

3. Remove the main board by pulling it with both hands.

Warning: The FBT is charged with high voltage. Before removing the Anode Cap, discharge the voltage through one of the heat sinks on the main board.

1. Remove the speaker by pressing the tension rib.

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