Samsung CW25M064NRXXEC Color Television Receiver Service Manual

Introduction

This document serves as a comprehensive service manual for the Samsung CW25M064NRXXEC Color Television Receiver, built on the KS7A(P) REV.1 chassis. It provides essential information for technical personnel involved in the maintenance, repair, and adjustment of the television receiver.

The manual covers detailed specifications, alignment and adjustment procedures, exploded views for mechanical assembly, comprehensive electrical and PCB parts lists, and various schematic diagrams to facilitate troubleshooting and component replacement.

Contents Overview

The service manual is structured into the following key sections:

1. Specifications
2. Alignment and Adjustments
3. Exploded Views and Parts List
4. Electrical Parts List
5. PCB Diagram
6. Schematic Diagrams

1. Specifications

The Samsung CW25M064NRXXEC Color Television Receiver is designed for various global markets, supporting multiple color demodulation systems and sound receiving methods. Key specifications include:

• Origin Mark: Made in Local Country (Factory) or Made By Samsung
• Color Demodulation: PAL/SECAM/NTSC4.43/NTSC3.58 (NTSC3.58 is optional), (SECAM-L', L is optional)
• Sound Receiving Way: Quasi-split (Related to VCTI)
• Sound Demodulation: Virtual Dolby/Nicam/Stereo/Line Stereo
• Antenna: 75ohm Din - Jack (V/U)
• Channel Search: Programmable F/S
• Channel Numbers: 100 CH PROGRAM MEMORY
• Input Voltage:
  • East - Asia, Middle-East Asia, Africa: 100V ~ 260V
  • CIS: 160V ~ 300V
  • Europe: 230V
  • Other: 240V
• Power Input Frequency: 50/60Hz
• Power STR: Free Volt (X6757), Single Volt (X6750)
• Power Insulation: SMPS/COLD
• Receiving (P/G) CH: VF: 2 ~ 13, UHF: 14 ~ 69, CATV: S1~S41
• Brand/Buyer: SAMSUNG/Depend on the Buyer
• Safety: Depend on the country
• Power Cord/Polarity: CP2/No(4.0), AP2/Yes, EP2/No
• Character Options:
  • 2T-PIP/1T-PIP/No PIP
  • ANT display (Option)
  • DNIe Jr (Option)
  • FM Radio (Option)

2. Alignment and Adjustments

2-1 General Alignment Instructions

For optimal performance, a color TV-VCR typically requires only minor touch-up adjustments upon installation. Technicians should verify basic characteristics such as height, horizontal and vertical sync, and focus.

The picture should be observed for good black and white details. If color shading is present, demagnetization, purity, and convergence adjustments are necessary. Use specified test equipment or its equivalent, ensuring correct impedance matching.

Safety Precaution: To protect against shock hazard, an isolation transformer must be used. Do not connect or disconnect any wires while the TV is turned on. Ensure the power cord is disconnected before replacing any parts. Avoid overloading the TV's front-end with excessive signal from a sweep generator, which can distort test results. Connect the TV only to an AC power source with the voltage and frequency specified on the backcover nameplate.

2-2 Automatic Degaussing

A degaussing coil is integrated around the picture tube, making external degaussing generally unnecessary after moving the TV. However, proper degaussing is crucial upon initial installation.

The degaussing coil activates for approximately 1 second when the power is switched ON. If the set is moved or turned in a different direction, the power should remain OFF for at least 10 minutes before powering on again.

If the chassis or cabinet parts become magnetized, resulting in poor color purity, an external degaussing coil should be used. Slowly move the degaussing coil around the picture tube's faceplate, sides, and front, then slowly withdraw the coil to about 6 feet before turning power OFF. If color shading persists, perform Color Purity and Convergence adjustments.

2-3 High Voltage Check

CAUTION: This chassis has no high voltage adjustment. The B+ power supply should maintain +135 volts with 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 Brightness and Contrast controls to minimum (zero beam current).
3. Adjust Brightness and Contrast controls to both extremes. Ensure the high voltage does not exceed 30 KV under any conditions.

2-4 FOCUS Adjustment

1. Input a crosshatch pattern.
2. Adjust the tuning control for the clearest picture.
3. Adjust the FOCUS control for well-defined scanning lines in the center area of the screen.

2-5 SCREEN Adjustment

1. Input a Toshiba Pattern. If a Toshiba pattern is unavailable, enter "Service Mode" and select "Test pattern 2" (Toshiba pattern).
2. Enter "Service Mode".
3. Select "G2-Adjust".
4. Set the values as example: IBRM = 175, WDRV = 110, CDL = 250, COLR G B = 110 110 110.
5. Turn the SCREEN VR until "Read Cutoff" and "Read Drive" are green. (Incorrect SCREEN Voltage may result in "Read Cutoff" and "Read Drive" being red).

2-6 White Balance Adjustment

1. Warm up the TV set for at least 30 minutes.
2. Enter the Service Mode by pressing the remote-control keys in the following sequence: Power Off → Info → Menu → Mute → Power On.
3. Initialize all set data.
4. Input a Toshiba pattern.
5. Using a probe (CA100), perform the White Balance adjustments:
   • Adjust Low-Light: Adjust Sub Brightness to set Y. Adjust G Cutoff to set Y. Adjust R Cutoff to set X.
   • Adjust High-Light: Adjust Sub Contrast to set Y. Adjust B Drive to set Y. Adjust R Drive to set X.
6. Check the value of Low-Light. If necessary, readjust Low-Light.
7. Check the value of High-Light. If necessary, readjust High-Light.

2-7 When adjusting Screen Voltage and White Balance

1. Screen Voltage and White Balance are interrelated. Both adjustments must be correct.
2. Adjust Screen Voltage before White Balance Adjustments. Ensure Screen Voltage is correct.
3. If White Balance has been readjusted, re-check Screen Voltage.
4. After adjustments are complete, check for the following:
   • If spots appear on the screen after pressing the Power On/Off key, readjust Screen Voltage.
   • If flyback lines appear on the screen, readjust Screen Voltage.

2-8 Factory Adjustment

2-8-1 Service Mode

To enter the "Service Mode", press the remote-control keys in this sequence:

• Without Factory remote-control: PICTURE OFF → INFO → ⊞ → MENU → MUTE → PICTURE ON
• With Factory remote-control: PICTURE ON → INFO → ⊞ → FACTORY

2-8-2 Factory Mode OSD (On-Screen Display)

The OSD provides access to various adjustment parameters. The "ADJUST" menu includes settings for Deflection, Video Adjustments (1, 2, 3), Option, YC Delay, Test Pattern, EEPROM, Bus Stop, Check Sum, Reset, and G2 Adjust.

Detailed tables are provided for Deflection (PAL/NTSC Offset), Video Adjust 1, Video Adjust 2, Video Adjust 3, Option settings, and YC Delay, specifying minimum, maximum, ET (Estimated Target), G/R (Green/Red), and remarks (Adjust/FIX).

The EEPROM section lists numerous factory control parameters by SubAddress, including Dynamic Contrast, Brightness, Sharpness, Color, Tint, Movie settings, PIP Brightness, TTX settings, OSD/PIP Contrast, OSD/PIP Brightness, and various audio equalization settings (Bass, Treble for Standard, Music, Movie, Speech modes), RGB/DVD Brightness, Contrast, Saturation, and other video adjustments. Each parameter has a Remark (FIX), Minimum, Maximum, and Initial value.

3. Exploded Views and Parts List

This section provides an exploded view diagram of the Samsung CW25M064NRXXEC television receiver, illustrating the assembly of its main components. Accompanying the diagram is a comprehensive parts list. This list includes the Code No., Description/Specification, Quantity (Q'ty), and S.N.A (Service Not Available) status for each component, aiding in identification and ordering of replacement parts. For updated part codes, users can refer to the Samsung ITSELF web site at http://itself.sec.samsung.co.kr.

4. Electrical Parts List

This section details the electrical components of the Samsung CW25M064NRXXEC television receiver. It is organized by assembly type (e.g., ASSY CPT, ASSY COVER FRONT, ASSY ACCESSORY, ASSY LABEL, ASSY P/MATERIAL, ASSY BOX, ASSY CHASSIS) and then by individual component. Each entry includes the Level, Location Number (Loc. No.), Code Number (Code No.), Description/Specification, and Remark (S.N.A. for Service Not Available). The list covers a wide range of electronic parts such as CRTs, coils, clamps, remote controls, speakers, PCBs, screws, tapes, connectors, diodes (rectifier, switching, zener), transistors, thermistors, capacitors (ceramic, film, aluminum electrolytic), crystals, filters, relays, fuses, jacks, inductors, and various other discrete components, providing essential information for circuit repair and component sourcing. For updated part codes, users can refer to the Samsung ITSELF web site at http://itself.sec.samsung.co.kr.

5. PCB Diagrams

This section presents the PCB (Printed Circuit Board) diagrams for the Samsung CW25M064NRXXEC television receiver. Specifically, it includes the "MAIN (TOP)" PCB diagram, which illustrates the layout of components on the main circuit board. These diagrams are crucial for technicians to identify component locations, trace circuits, and perform accurate repairs and troubleshooting.

6. Schematic Diagrams

This section provides detailed schematic diagrams for the Samsung CW25M064NRXXEC television receiver, essential for understanding the electronic circuitry and for troubleshooting. These diagrams are for internal use and cannot be used without Samsung's authorization.

The schematic diagrams are categorized as follows:

• 6-1 MAIN: The primary schematic diagram detailing the main processing unit and its interconnections.
• 6-2 POWER: Schematic diagram for the power supply unit, including details on power regulation and distribution.
• 6-3 CRT: Schematic diagram focusing on the Cathode Ray Tube (CRT) drive circuits and related components.
• 6-4 JACK: Schematic diagram illustrating the audio/video input/output jack connections and associated circuitry.
• 6-5 PIP MODULE: Schematic diagram for the Picture-In-Picture (PIP) module, detailing its internal components and connections.
• 6-6 CRT 2: Additional schematic diagram related to the CRT, possibly detailing specific sub-circuits or adjustments.
• 6-7 CONTROL: Schematic diagram for the control panel and remote control interface, including buttons and LED indicators.
• 6-8 A/V SIDE: Schematic diagram for the Audio/Video (A/V) input/output side, detailing signal paths and related components.

These diagrams are vital for diagnosing circuit faults, understanding signal flow, and performing component-level repairs.