DAEWOO PF2720, PF2730, PF3220, PF3230 Service Manual

FILE NO. SM-CTV-O-056

COLOR TELEVISION

SERVICE MANUAL

MODEL NO.

PF2720/PF2730

PF3220/PF3230

CHASSIS NO. CH-16CD

Please read this manual carefully before service.

SERVICE MANUAL

TABLE OF CONTENTS

SAFETY INSTRUCTIONS AND MAINTENANCE

X-Ray Radiation Precaution ..............................................................................................1

Safety Precaution................................................................................................................1

Product Safety Notice.........................................................................................................2

Maintenance ......................................................................................................... 3

SPECIFICATIONS..........................................................................................................4

KEY ICS AND ASSEMBLIES.................................................................................4

.....................................1

SYSTEM BLOCK DIAGRAMS

Structure Block Diagram....................................................................................................5

Block Diagram for Supply Voltage System.....................................................................6

...............................................................................5

SERVICE DATA...............................................................................................................7

Technical Data of Key ICs..................................................................................................7

Service Data of Key ICs.....................................................................................................22

Waveforms of Key Points...................................................................................................29

ADJUSTMENTS..............................................................................................................37

Set-up Adjustments.............................................................................................................37

Circuit Adjustments.............................................................................................................40

Service Mode and Bus Data..............................................................................................41

TROUBLESHOOTING FLOW CHARTS.........................................................47

APPENDIX

1. Circuit Diagrams

2. Printed Circuit Board Diagrams

3. Final Wiring Diagrams

4. Exploded Views

SAFETY INSTRUCTIONS AND MAINTENANCE

WARNING: BEFORE SERVICING THIS CHASSIS, READ THE “X-RAY RADIATION PRECAUTION”, “SAFETY PRECAUTION”AND “PRODUCT SAFETY NOTICE INSTRUCTIONS BELOW.

”

X-RAY RADIATION PRECAUTION

1. The EHT must be checked every time the TV is serviced to ensure that the CRT does not emit X-ray radiation as result of excessive EHT voltage. The maximum EHT voltage permissible in any operating circumstances must not exceed the rated value. When checking the EHT, use the High Voltage Check procedure in this manual using an accurate EHT voltmeter.

2. The only source of X-RAY radiation in this TV is the CRT. The TV minimizes X-RAY radiation, which ensures safety during normal operation. To prevent X-ray radiation, the replacement CRT must be identical to the original fitted as specified in the parts list.

3. Some components used in this TV have safety related characteristics preventing the CRT from emitting X-ray radiation. For continued safety, replacement component should be made after referring the PRODUCT SAFETY NOTICE below.

4. Service and adjustment of the TV may result in changes in the nominal EHT voltage of the CRT anode. So ensure that the maximum EHT voltage does not exceed the rated value after service and adjustment.

SAFETY PRECAUTION

WARNING: REFER SERVICING TO QUALIFIED SERVICE PERSONNEL ONLY.

1. The TV has a nominal working EHT voltage. Extreme caution should be exercised when working on the TV with the back removed.

1.1 Do not attempt to service this TV if you are not conversant with the precautions and procedures for working on high voltage equipment.

1.2 When handling or working on the CRT, always discharge the anode to the TV chassis before removing the anode cap in case of electric shock.

1.3 The CRT, if broken, will violently expel glass fragments. Use shatterproof goggles and take extreme care while handling.

1.4 Do not hold the CRT by the neck as this is a very dangerous practice.

2. It is essential that to maintain the safety of the customer all power cord forms be replaced exactly as supplied from factory.

3. Voltage exists between the hot and cold gro und when the TV is in operation. Install a suitable isolating transformer of beyond rated overall power when servicing or connecting any test equipment for the sake of safety.

SERVICE MANUAL

4. When replacing ICs, use specific tools or a static-proof electric iron with small power (below 35W).

5. Do not use a magnetized screwdriver when tightening or loosing the deflection yoke assembly to avoid electronic gun magnetized and decrement in convergence of the CRT.

6. When remounting the TV chassis, ensure that all guard devices, such as nonmetal control buttons, switch, insulating sleeve, shielding cover, isolating resistors and capacitors, are installed on the original place.

7. Replace blown fuses within the TV with the fuse specified in the parts list.

8. When replacing wires or components to terminals or tags, wind the leads around the terminal before soldering. When replacing safety components identified by the international hazard symbols on the circuit diagram and parts list, it must be the company-approved type and must be mounted as the original.

9. Keep wires away from high temperature components.

PRODUCT SAFETY NOTICE

CAUTION: FOR YOUR PROTECTION, THE FOLLOWING PRODUCT SAFETY NOTICE SHOULD BE READ CAREFULLY BEFORE OPERATING AND SER VICING THIS TV SET.

1. Do not slap or beat the cabinet or CRT, since this may result in fire or explosion.

2. Never allow the TV sharing a plug or socket with other large-power equipment. Doing so may result in too large load, thus causing fire.

3. Do not allow anything to rest on or roll over the power cord. Protect the power cord from being walked on, modified, cut or pinched, particularly at plugs.

4. Do not place any objects, especially heavy objects and lightings, on top of the TV set. Do not install the TV near any heat sources such as radiators, heat registers, stove, or other apparatus that produce heat.

5. Service personnel should observe the SAFETY INSTRUCTIONS in this manual during use and servicing of this TV set. Otherwise, the resulted damage is not protected by the manufacturer.

6. Many electrical and mechanical components in this chassis have special safety-related characteristics. These characteristics are often passed unnoticed by a visual inspection and the X-ray radiation protection afforded by them cannot necessarily be obtained by using replacements rated at higher voltages or wattage, etc. Components which have these special safety characteristics in this manual and its supplements are identified by the international hazard symbols on the circuit diagram and parts list. Before replacing any of these components read the parts list in this manual carefully. Substitute replacement components which do not have the same safety characteristics as specified in the parts list may create X-ray radiation.

SERVICE MANUAL

Safety Symbol Description

The lightning symbol in the triangle tells you that the voltage inside this product may be strong enough to cause an electric shock. Extreme caution should be exercised when working on the TV with the back removed. This is an international hazard symbol, telling you that the components identified by the symbol have special safety-related characteristics.

FDA This symbol tells you that the critical components identified by the FDA marking have

special safety-related characteristics.

UL This symbol tells you that the critical components identified by the UL marking have

special safety-related characteristics.

MAINTENANCE

1. Install the TV set on a stable and level surface. Do not place the set near or over a radiator or heat register, or where it is exposed to direct sunlight.

2. Do not install the TV set in a place exposed to rain, water, excessive dust, mechanical vibrations or impacts.

3. Allow enough space (at least 10cm) between the TV and wall or enclosures for proper ventilation.

4. Slots and openings in the cabinet should never be blocked by clothes or other objects.

5. Please power off the TV set and disconnect it from the wall immediately if any abnormal condition are met, such as bad smell, belching smoke, sparkling, abnormal sound or no picture/sound/raster. Hold the plug firmly when disconnecting the power cord.

6. Unplug the TV set from the wall outlet before cleaning or polishing it. Use a dry soft cloth for cleaning the exterior of the TV set or CRT screen. Do not use liquid cleaners or aerosol cleaners.

SERVICE MANUAL

SPECIFICATIONS

MODEL PF2720 PF2730 PF3220 PF3230

Television System NTSC-M Channel Coverage VHF 2-13, UHF 14~69

Cable TV Coverage

Channels Preset 181 Antenna Input 75 ohm (unbalanced)

Screen Dimensions Audio Output 5W+5W 5W+5W

Power Source ~120Vac 60Hz Unit Weight 97.9lbs. ( 44.5kg) 156lbs. ( 71kg)

Unit Dimensions

Packaged Dimensions Power Consumption

Hyper Band (AA~ZZ, AAA, BBB)/Ultra Band (65~94, 100~125)

21.26x 15.94 in

29.09x22.83x19.29 in.

739x580x490mm

33.07x26.38x23.43in. 840x670x595mm

Mid Band (A-8~A-1, A~I)/Super Band (J~W)

25.20x 18.82 in

540x405 mm

135W 170W

640x478 mm

33.70x26.34x22.05 in.

856x669x560mm

40x30.55x27.76in. 1016x776x705mm

KEY ICS AND ASSEMBLIES

Table 1 Key ICs and Assemblies

Serial No. Position No. Model No. Function Description

1 N201 TDA937X UOC 2 N202 AT24C16 EEPROM 3 NB01 MSP3440G-B8 BTSC 4 N401 TDA8350 Vertical output circuit 5 N361 TDA8944J Sound power amplifier 6 N901 TA1219AN 7 N902 TC90A49P 8 NY01 TDQ6108JF 9 A101 TDQ-6F2-M

10 IC801 STR-G8626

TV/AV switch circuit COMB filter Video amplifier Tuner Power supply circuit

SYSTEM BLOCK DIAGRAMS

Structure Block Diagram

SERVICE MANUAL

45V

SERVICE MANUAL

Block Diagram for Supply Voltage System

SERVICE MANUAL

SERVICE DATA

Technical Data of Key ICs TDA937X (N201)

UOC

1. General Description

The various versions of the TDA937X PS/N2 series combine the functions of a video processor together with a μ-Controller and US Closed Caption decoder. The ICs are intended to be used in economy television receivers with 90° and 110° picture tubes. The ICs have supply voltages of 8V and 3.3V and they are mounted in an S-DIP 64 envelope. The features are given in the following feature list. The differences between the various ICs are given in the table on page 4.

2. Features TV-signal processor

• Multi-standard vision IF circuit with alignment-free PLL demodulator

• Internal (switchable) time-constant for the IF-AGC circuit

• A choice can be made between versions with mono intercarrier sound FM demodulator and versions with QSS IF amplifier.

• The mono intercarrier sound versions have a selective FM-PLL demodulator which can be switched to the different FM sound frequencies (4.5/5.5/6.0/6.5 MHz). The quality of this system is such that the external band-pass filters can be omitted.

• Source selection between ‘internal’ CVBS and external CVBS or Y/C signals

• Integrated chrominance trap circuit

• Integrated luminance delay line with

adjustable delay time

• Picture improvement features with peaking

(with variable positive/negative overshoot

ratio), black stretching and Dynamic Skin

Tone Control

• Integrated chroma band-pass filter with switchable centre frequency

• Only one reference (12 MHz) crystal required for the μ-Controller, Teletext- and the colour decoder

• PAL/NTSC colour decoder with automatic

search system

• Internal base-band delay line

• RGB control circuit with ‘Continuous Cathode

Calibration’, white point and black level offset adjustment so that the colour temperature of the dark and the light parts of the screen can be chosen independently.

• Linear RGB or YUV input with fast blanking for external RGB/YUV sources. The Text/OSD signals are internally supplied from theμ-Controller/Teletext decoder

• Contrast reduction possibility during mixed-mode of OSD and Text signals

• Horizontal synchronization with two control

loops and alignment-free horizontal oscillator

• Vertical count-down circuit

• Vertical driver optimized for DC-coupled

vertical output stages

• Horizontal and vertical geometry processing

• Horizontal and vertical zoom function for 16 :

9 applications

• Horizontal parallelogram and bow correction

for large screen picture tubes

• Low-power start-up of the horizontal drive

circuit

3.Pin

SERVICE MANUAL

4.Block Diagram

SERVICE MANUAL

5.Refer to Table 2 about Functions and Service Data of the IC's Each Pin.

SERVICE MANUAL

AT24C16 (N202) EEPROM

1. Features

·Low Voltage and Standard Voltage Operation

5.0 (V

2.7 (V

2.5 (V

1.8 (V

= 4.5V to 5.5V)

= 2.7V to 5.5V)

= 2.5V to 5.5V)

= 1.8V to 5.5V)

·Internally Organized 128 x 8 (1K), 256 x 8 (2K),

512 x 8 (4K),1024 x 8 (8K) or 2048 x 8 (16K)

·2-Wire Serial Interface

·Bidirectional Data Transfer Protocol

·100 kHz (1.8V, 2.5V, 2.7V) and 400 kHz (5V)

Compatibility

·Write Protect Pin for Hardware Data Protection

·8-Byte Page (1K, 2K), 16-Byte Page (4K, 8K,

16K) Write Modes

·Partial Page Writes Are Allowed

·Self-Timed Write Cycle (10 ms max)

·High Reliability

Endurance: 1 Million Cycles Data Retention: 100 Years

·Automotive Grade and Extended Temperature

Devices Available

·8-Pin and 14-Pin JEDEC SOIC and 8-Pin PDIP

Packages

2.Description

The AT24C01A/02/04/08/16 provides 1024/2048/4096/8192/16384 bits of serial electrically erasable and programmable read only memory (EEPROM) organized as 128/256/512/1024/2048 words of 8 bits each. The device is optimized for use in many industrial and commercial applications where low power and low voltage operation are essential. The AT24C01A/02/04/08/16 is available in space saving 8-pin PDIP, 8-pin and 14-pin SOIC packages and is accessed via a 2-wire serial interface. In addition, the entire family is available in 5.0V (4.5V to 5.5V), 2.7V (2.7V to

5.5V), 2.5V (2.5V to 5.5V) and 1.8V (1.8V to

5.5V) versions.

Pin Configurations

3.Block Diagram

SERVICE MANUAL

Fig.6

4.Refer to Table 3 about Functions and Data of the IC’ s Pins.

SERVICE MANUAL

MSP3440G-B8 (NB01) Multistandard Sound Processor Family

Release Note: Revision bars indicate significant changes to the previous edition. The hardware and software description in this document is valid for the MSP34X0G version B5 and following versions.

1. Introduction

The MSP34X0G family of single-chip Multistandard Sound Processors covers the sound processing of all analog TV-Standards worldwide, as well as the NICAM digital sound standards. The full TV sound processing, starting with analog sound IF signal-in, down to processed analog AF-out, is performed on a single chip. Figure 7 shows a simplified functional block diagram of the MSP34X0G.

This new generation of TV sound processing ICs now includes versions for processing the multichannel television sound (MTS) signal conforming to the standard recommended by the Broadcast Television Systems Committee (BTSC). The DBX noise reduction, or alternatively MICRONAS Noise Reduction (MNR) is performed alignment free

2. Block Diagram

Other processed standards are the Japanese FM-FM multiplex standard (EIA-J) and the FM Stereo Radio standard. Current ICs have to perform adjustment procedures in order to achieve good stereo separation for BTSC and EIA-J. The MSP34X0G has optimum stereo performance without any adjustments. All MSP34X0G versions are pin and software downward-compatible to the MSP34X0D. The MSP34X0G further simplifies controlling software. S tandard selection requires a single I The MSP34X0G has built-in automatic Functions: The IC is able to detect the actual sound standard automatically (Automatic Standard Detection). Furthermore, pilot levels and identification signals can be evaluated internally with subsequent switching between mono/stereo/bilingual; no I necessary (Automatic Sound Selection). The ICs are produced in submicron CMOS technology. The MSP34X0G is available in the following packages: PLCC68, PSDIP64, PSDIP52, PQFP80 and PLQFP64.

C transmission only.

C interaction is

Fig. 7 Simplified Functional Block Diagram of the MSP34X0G

3. Refer to Table 4 about Functions and Service Data of MSP34X0G’s Each Pins.

SERVICE MANUAL

(

set )

TDA8350 (N401)

DC-coupled Vertical Deflection and East-West Output Circuit

1. Features

·Few external components

·Highly efficient fully DC-coupled vertical output

bridge circuit

·Vertical fl yback switch

·Guard circuit

·Protection against：

-short-circuit of the output pins

-short-circuit of the output pins to Vp

3. Block Diagram

·High EMC immunity due to common mode

inputs

·Temperature (thermal) protection

·East-West output stage with one single

conversion resistor.

2. General Description

The TDA8350Q is a power circuit for use in 90° and 110° colour deflection systems for field frequencies of 50 to 120 Hz. The circuit provides a DC driven vertical deflection output circuit, operating as a highly efficient class G system and an East-West driver for sinking the diode modulator current.

-V

Fig. 8

4. Refer to Table 5 about Functions and Service Data of TDA8350Q’s Pins.

TDA8944J (N361)

Audio Power Amplifier

SERVICE MANUAL

1. General Description

The TDA8944J is a dual-channel audio power

amplifier with an output power of

2 ´ 7 W at a n 8 W load and a 12 V supply. The

circuit contains two Bridge Tied Load

(BTL) amplifiers with an all-NPN output stage and

standby/mute logic. The TDA8944J

comes in a 17-pin DIL-bent-SIL (DBS) power

package. The TDA8944J is

printed-circuit board (PCB) compatible with all

other types in the TDA894x family.

One PCB footprint accommodates both the mono

and the stereo products.

3.Block Diagram

2. Features

Few external components

Fixed gain

Standby and mute mode

No on/off switching plops

Low standby current

High supply voltage ripple rejection

Outputs short-circuit protected to ground,

supply and across the load

Thermally protected

Printed-circuit board compatible

Pinning

Fig.10 Pin configuration.

5. Refer to Table 6 about Functions and Service Data of TDA8944J's Pins.

SERVICE MANUAL

TA1219AN (N901) Audio/Video Switching IC for TVs

The TA1219AN is an audio/video switching IC for TV Sets. Conforming to I2C bus standards, it allows you to perform various switching operations through the bus lines by using a microcomputer. Furthermore, since the presence of a signal on its sync signal output pin can be determined by a microcomputer , it is possible to check each input/output channel (self-diagnosis). This IC has the same pin assignments as the TA1218AN (SDIP42), a 2-channel output version of the TA1219AN, so these chips are pin compatible on pins 3 to 20 and 23 to 40 in TA1218AN.

1. Features

·I

C bus control

·Video: 5-channel inputs and 1-channel outputs (2 channels conforming to S system)

·Audio: 5-channel inputs and 2-channel outputs

·Self-diagnostic function

·ADC inputs based on European 21-pin standards

·ADC inputs based on S1/S2 terminal standards

·Switchable subaddress

2. Block Diagram

SERVICE MANUAL

Fig.11

3. Refer to Table 7 about Functions and Service Data of TA1219AN’s Pins.

SERVICE MANUAL

3. Pin Assignment

2. Block Diagram

Fig.14

4. Refer to Table 8 about Fu nctions and Service Data of TC90A49P’s Pins.

TC90A49P (N902) COMB Filter

1. Features

TV format : NTSC (3.58), PAL, M-PAL, and N-

PAL

Dynamic comb filter Vertical edge enhancement circuit PLL 8 × multiplier circuit Internal 8-bit 4 fsc AD converter Internal 8-bit precision 8 fsc DA converter (2 ch) Sync tip clamp circuit Internal 4H-line memory

I C bus interface Package : DIP 20-pin and SOP 24-pin 5 V single power supply

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