DAEWOO Color Television CHASSIS : SC-140 Model : DSC-3210E
Service mode
To switch the TV set into service mode please see instruction below.
1 - Select pr. number 91
2 - Adjust sharpness to minimum and exit all menu.
3 - Quickly press the key sequence : RED - GREEN– Menu
To software version is displayed beside the word Service, e.g. “ SERVICE V1.00A”.
To exit SERVICE menu press menu key or St-By key.
Service mode navigation
Pr Up or Down remote keys > cycle through the service items available.
Vol [ - +] remote keys > Decrement / Increment the values within range.
0~7 digit keys > Toggle bits 0~7 in option byte.
Default settings for wp 895
Microcontroller configuration : Option bits
These option bits are available from Service mode. First find the OPTION control, and then use keys 0...7 on the remote keypad to control bits 0 to 7 respectively. The table below shows the options available. [Set all the unused bits, marked 'X', to be 0 for future compatibility.]
Local oscillator alignment
Tune a color bar pattern. The Frequency of the signal carrier must be accurate (Max +/- 10khz deviation from the nominal channel frequency).
Find "AFT" item in service mode.
Adjust the coil L150 to bring the cursor to central position : 32.
G2 alignment
- Tune a color bar pattern.
- Find the "G2 - SCREEN" item in service mode.
- Adjust screen volume (on FBT) to bring the cursor to central position : 32.
White balance
- Select a dark picture and adjust RED BIAS and GRN BIAS to the desired colour temperature.
- Select a bright picture and adjust REC, GRN and BLUE GAIN to the desired dolour temperature.
White balance
- Select a dark picture and adjust RED BIAS and GRN BIAS to the desired colour temperature.
- Select a bright picture and adjust REC, GRN and BLUE GAIN to the desired dolour temperature.
Vertical geometry
Adjust V.LINEAR (linearity), S CORRECT
(S. Correction), VERT SIZE (Vertical amplitude),
VERT CENT (vertical canting) to compensate for vertical distortion.
Horizontal picture centering
Adjust HOR CEN(Horizontal center) to have the picture in the center of the screen.
Ea-West
Adjust the PARABOLA, HOR WIDTH, CORNER, HOR PARAL, EW TRAPEZ, H BOW, to compensate for geometrical distortion,
AGC
- Adjust the antenna signal level at 70 dB V 2
- Tune a color bar pattern.
- Find the “ AGC” item in service mode.
- Adjust AGC volume ( RB10 ) to bring the cursor to central position : 32.
Data Capture
The Video Front End section takes in the analogue Composite Video and Blanking Signal (CVBS), and from this extracts the required data, which is then decoded and stored in memory. The extraction of the data is performed in the digital domain. The first stage is to select and convert the analogue CVBS signal into a digital form. This is done using 8 bit ADC sampling at 20.25 Mhz. The digital data services transmitted in the VBI are selected and acquired separately form the video part. This is done by the use of an adaptive data slicer. The following data types can be extracted : 625 line World System Teletext (WST), VPS, WSS. The data is acquired and decoded by the teletext decoder (TPU), then stored in an SRAM interface.
Data Capture Features
Video Signal Quality detector
Data Capture for 625 line WST
Data Capture for VPS data (PDC system A)
Data Capture for Wide Screen Signaling (WSS) bit decoding
Real-time capture and decoding for WST Teletext in Hardware, to enable optimized microprocessor throughput 10 page memory stored On-Chip.
Inventory of transmitted Teletext pages stored in the Page Table
Signal quality detector for WST data
Comprehensive Teletext language coverage
Full Field Vertical Blanking Interval (VBI) data capture of WST data.
MSP341x Multi-standard Sound Processor
The MSP 341x is designed as a single-chip Multi-standard Sound Processor for applications in analogue and digital TV sets, video recorders, and PC cards.
The MSP3411 has all functions of MSP3410 with the addition of a virtual surround sound feature.
A Surround sound affect can be reproduced with two loudspeakers. The MSP3411 includes virtualized algorithm “3D Panorama "which has been approved by the Dolby laboratories for compliance with the “ Virtual Dolby Surround "technology. In addition, the MSP3411 includes Micronase “ panorama” algorithm.
MSP 341x features :
- sound IF input
- No external filters required
- Stereo baseband input via integrated AD converters
- Two pairs of DA converters
- Two carrier FM or NICAM processing
- AVC : Automatic Volume Correction
- Bass, treble, volume processing
- Full SCART in/out matrix without restrictions
- Improved FM-identification
- Demodulator short programming
- Autodetection for terrestrial TV - sound standards
- Precise bit-error rate indication
- Automatic switching from NICAM to FM/AM or vice versa
- Improved NICAM synchronization algorithm
- Improved carrier mute algorithm
- Improved AM-demodulation
- Reduction of necessary controlling
- Less external components.
Demodulator and NICAM Decoder Section
The MSP 341x is designed to simultaneously perform digital demodulation and decoding of NICAM-coded TV stereo sound, as well as demodulation of FM or AM mono TV sound. Alternatively, two carrier FM systems according to the German terrestrial specs can be processed with the MSP 341x.
The MSP 341x facilitates profitable multi-standard capability, offering the following advantages:
- Automatic Gain Control (AGC) for analogue input: input range: 0.10 - 3 Vpp
- integrated A/D converter for sound-IF input
- all demodulation and filtering is performed on chip and is individually programmable
- easy realization of all digital NICAM standards (B/G, I, L and D/K)
- FM-demodulation of all terrestrial standards (include identification decoding)
- no external filter hardware is required
- only one crystal clock (18.432 MHz) is necessary.
DSP-Section (Audio Baseband Processing)
- flexible selection of audio sources to be processed
- performance of terrestrial de-emphasize systems (FM, NICAM)
- digitally performed FM-identification decoding and de-matrixing
- digital baseband processing: volume, bass, treble
- simple controlling of volume, bass, treble.
Analogue Section
- two selectable analogue pairs of audio baseband input (= two SCART inputs) input level: <2 V RMS,
input impedance: >25
- one selectable analogue mono input (i.e. AM sound): Not used in this chassis
- two high-quality A/D converters, S/N-Ratio: >85 dB
- 20 Hz to 20 kHz bandwidth for SCART-to-SCART copy facilities
- loudspeaker: one pair of four-fold oversampled D/A converters. Output level per channel:
max. 1.4 VRMS output resistance: max. 5 . S/N-ratio: >85 dB at maximum volume Max.
noise voltage in mute mode: < 10 V (BW: 20 Hz... 16kHz)
- one pair of four-fold oversampled D/A converters supplying a pair of SCART-outputs.
output level per channel: max. 2 V RMS, output resistance: max. 0.5 , S/N-Ratio: >85 dB (20 Hz... 16 kHz)
NICAM plus FM/AM-Mono
According to the British, Scandinavian, Spanish, and French TV-standards, high-quality stereo sound is transmitted digitally. The systems allow two high-quality digital sound channels to be added to the already existing FM/AM-channel. The sound coding follows the format of the so-called Near Instantaneous Commanding System
(NICAM 728). Transmission is performed using Differential Quadrature Phase Shift Keying (DQPSK. Table below offers an overview of the modulation parameters.)
In the case of NICAM/FM (AM) mode, there are three different audio channels available: NICAM A, NICAM B, and FM/AM-mono. NICAM A and B may belong either to a stereo or to a dual language transmission. Information about operation mode and about the quality of the NICAM signal can be read by the controlling software via the control bus.
In the case of low quality (high bit error rate), the controlling software may decide to switch to the analogue FM/AM mono sound. Alternatively, an automatic NICAM-FM/AM switching may be applied.
German 2-Carrier System (DUAL FM System)
Since September 1981, stereo and dual sound programs have been transmitted in Germany using the 2-carrier system.
Sound transmission consists of the already existing first sound carrier and a second sound carrier additionally containing an identification signal. More details of this standard are given in Tables below. For D/K very similar system is used.
TDA 4470-Multistandard Video-IF and Quasi Parallel Sound Processor. TDA 4470 is an integrated bipolar circuit for multi-standard video/sound IF (VIF/SIF) signal processing in TV/VCR and multimedia applications. The circuit processes all TV video IF signals with negative modulation (e.g., B/G standard), positive modulation (e.g., L standard) and the AM, FM/NICAM sound IF signals.
Features
- 5V supply voltage ; low power consumption.
- Active carrier generation by FPLL principle (frequency-phase-locked-loop) for true synchronous demodulation.
- Very linear video demodulation, good pulse response and excellent intermodulation figures.
- Alignment-free AFC without external reference circuit, polarity of the AFC curve is switchable.
- VIF-AGC for negative modulated signals (peak sync. detection) and for positive modulation (peak white/black level detector).
- Tuner AGC with adjustable take over point.
- Alignment-free quasi parallel sound (QPS) mixer for FM/NICAM sound IF signals.
- Intercarrier output signal is gain controlled (necessary for digital sound processing).
- Complete alignment-free AM demodulator with gain controlled AF output.
- Separate SIF-AGC with average detection
- Two independent SIF inputs
- Parallel operation of the AM demodulator and QPS mixer (for NICAM-L stereo sound).
The TDA8944J( TDA 8946J) is a dual-channel audio power amplifier with an output power of 2 x 7W (2 X 15W) at an 8 load and a 12V supply. The circuit contains two Bridges Tied Load(BTL) amplifiers with an all-NPN output stage and standby/mute logic. The TDA8944J comes in a 17-pin DIL power package.
The TDA835xJ are power circuit for use in 90o and 110o color deflection systems for field frequencies of 25 to 200Hz and 16/9 picture tubes. The circuit provides a DC driven vertical deflection output circuit, operating as a highly efficient class G system. Due to the full bridge output circuit the deflection coils can be DC coupled.
The IC is constructed in a Low Voltage DMOS process that combines Bipolar, CMOS and DMOS devices.
MOS transistors are used in the output stage because of the absence of second breakdown.
The TDA6107Qincludes three video output amplifiers in one plastic DIL-Bent-SIL 9-pin medium power package, using high voltage DMOS technology, and is intended to drive the three cathodes of a color CRT directly. To obtain maximum performance, the amplifier should be used with black-current control.
Features
- Typical bandwidth of 5.5 MHz for an output signal of 60 Vpp
- High slew rate of 900V/ s
- No external components required
- Very simple application
- Single supply voltage of 200V
- Internal reference voltage of 2.5 V
- Fixed gain of 50.
- Black-current stabilization (BCS) circuit
- Thermal protection.
The STR-F6654is an hybrid IC with a build-in MOSFET and control IC, designed for fly-back converter type switch mode power supply applications.
- Small SIP fully isolated molded 5 pins package
- Many protection functions :
* Pulse-by-pulse overcurrent protection (OCP)
* Overvoltage protection with latch mode (OVP)
* Thermal protection with latch mode (TSD)
Schematic diagram and PWB
