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TV2KR - TXT
COLOUR TELEVISION RECEIVER
SERVICE MANUAL
SECIFICATION · SYSTEM · POWER INPUT · POWER CONSUMPTION · AERIAL IMPEDANCE · TUNER · RECEIVING CHANNELS
PAL/SECAM BG/DK/I AC 170-245(50/60Hz) 65W 75 OHM UNBALANCED FREQUENCY SYNTHESIZER TUNING VHF-L VHF-H UHF E2-S6 S7-S41 E21- E69
· PROGRAMME · PICTURE TUBE · SOUND OUTPUT · SPEAKER · AV JACKS
MAX. 100 PROGRAM MEMORIES 14", 15", 20", 21"; 90° 2.0W 3W 8OHM FULL SCART X 1
CAUTION: Before servicing the chassis, read the "Safely Precaution". "X -Ray radiation
Precaution" and "Product Safety Notice" in this manual.
X-RAY RADIATION PRECAUTION
1. Excessive high voltage can produce potentially hazardous X-RAY RADIATION. To Avoid such hazards the high voltage must be specified limit. The normal value of the high voltage of this receiver is 24.5KV +/-2KV under 230V AC power source. The high voltage must not exceed 27KV. 2. Each time a receiver requires servicing the high voltage should be checked following the HIGH VOLTAGE CHECK procedure in this manual. It is recommended the reading of the high voltage be recorded as a part of the service record. It is important to use an accurate and reliable high voltage meter. 3. The primary source of X -RAY RADIATION in this TV receiver is the picture tube. For continued X-RAY RADIATION protection, the replacement tube must be exactly the same type tube as used in this TV receiver. 4. Some parts in this receiver have special safety-related characteristics for X-RAY RADIATION protection. For continued safety, parts replacement should be undertaken only after referring the PRODUCT SAFETY NOTICE below.
SAFETY PRECAUTION
WARNING: Service should not be attempted by anyone unfamiliar with the necessary Precautions on this receiver. The following are the necessary precautions to be observed before servicing this chassis. 1. Since the power supply circuit of this receiver is directly connected to the AC power line. An isolation transformer should be used during any dynamic service to avoid possible shock hazard. 2. Always discharge the picture tube anode to the CRT conductive coating before handling the picture tube. The picture tube is highly evacuated and if broken, glass fragments will be violently expelled. Use shatterproof goggles and keep picture tube away from the unprotected body while handling. 3. When replacing a chassis in the cabinet, always be certain that all the protective devices are put back in place, such as: nonmetallic control; knobs, insulating covers, shields, isolation resistor-capacitor, network, etc. 4. When replacing parts or circuit boards, disconnect the power cord. 5. When replacing a high voltage resistor (metal oxide resistor) on circuit hoard, keep the resistor APP. 10mm(1/2 in.) away from circuit board. 6. Connection wires must be kept away from components with high voltage or high temperature. 7. If any fuse in this TV receiver is blown, replace it with the FUSE specified in the chassis parts list. 8. The receiver is designed to operate with 230V(50Hz) AC mains.
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PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety-related characteristics are often passed unnoticed by a visual inspection and the X-RAY RADIATON protection afforded by them cannot necessarily be obtained by using replacement components rated for higher voltage. The use of substitute replacement parts that do not have the same safety characteristics as specified in the parts list may create shock, fire, X-RAY RADIATION or other hazards.
GENERAL ADJUSTMENT AUTOMATIC DEGAUSSING
An automatic degaussing coil is attached around the picture tube, degaussing the tube properly in about one second after the set is switched on. If the receiver is moved or faced on a different direction, the power must be switched off at least 15 minutes in order that the automatic degaussing circuit operated properly. External degaussing is necessary if the automatic degassing proves ineffective after the set is moved.
B+ ADJUSTMENT
CAUTION: To avoid X-ray hazards and result in a nominal display width, B+ voltage must be set in
the scale of 110.0V+/-0.5V. 1. Make sure the AC power supply is 230V, 50Hz. 2. Switch on the TV receiver, tune in an active channel. 3. Measure the voltage between C318 on Main P.C. Board by DC voltmeter. 4. Set contrast, brightness, color to maximum. 5. Adjust RP301 on Main P. C. Board for B+110.0V+/-0.5V voltage reading.
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HIGH VOLTAGE CHECK
CAUTION: There is no high voltage adjustment in this chassis, B+110V voltage directly relates to
the high voltage. The high voltage does not exceed 27KV under any conditions. 1. Connect an accurate high voltage meter to the second anode cap of the picture tube. 2. Turn on the receiver, set brightness and contrast to minimum (Zero beam current). 3. Make sure the high voltage does not exceed 27KV. 4. NO matter whether the luminance, contrast and chrominance controls are set to maximum or minimum, the high voltage must be kept under 27KV.
FOCUSING
Receive a TV test pattern signal; adjust controls for optimum picture. Adjust Focus Control for a well-defined, sharpest display in the center area of the screen.
ADJUSTMENT AND SERVICING THE CHASSIS
SERVICE MODE
To enter the service mode, short service mode points on PCB (X202, pins 1&2) or press from ST-BY mode STATUS>MENU>MUTE>ST-BY on RC. TV will display service menu as following table 1 line by line. To select the parameter by using the `P+/P-' keys. To adjust the selected parameter by using the `V+/V-' keys. To quit the service mode, press the `TV' key on remote control when in the service mode. Table 1
SERVICE MODE (enter: to short service mode points or press from ST-BY mode STATUS>MENU>MUTE>ST-BY)
Control bits HS VHS VA VAZ VS SC CL Y IFO Vg2 Vg2BR Horizontal Shift Vertical Shift
Function
Value 31 30 30 1 33 22 7 7 32 OK sreen 32 VX
Notes
Vertical Amplitude Vertical expand (zoom) Vertical Slope S-Correction Cathode drive Level Y Delay IF PLL Offset adjusment Screen Voltage Alignment mode Brightness control setting voltage alignment mode in
50 .. 95 Volt drive
Screen VR (on the FBT)
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BLOR BLOG R G B AGC BCF OSO AGN IE2 ACL FSL BKS IFO AGCs FFI AV2 SVID PF RPO TSM TSH TBL TBM TBH DELAY STEP HOTEL LOCAL BRT CONTR 16:9
Black level off-set R Black level off-set G White point R White point G White point B AGC Take Over Point Black Current loop Failure Overscan Switch-Off Sound pre-amplifier +6 db RGB Insertion Enable Automatic Colour Limiting forced vertical slicing level BlacK Stretch IF frequency selection AGC time constant Fast filter IF-PLL AV2 inbut enabled SVID input enabled Peaking centre frequency RATIO PRE-/OVERSHOOT Limit between VHF1/VHF3 Limit between VHF3/UHF Code for band VHF-1 Code for band VHF-3 Code for band UHF Delay time for tuner 0-50 kHz, 1-62,5 kHz Hotel mode anabled 6/3buttons keyboard swich Brightness control in service mode Contrast control in service mode 16:9 mode enabled
32 32 32 32 32 35 TOP 0 1 1 1 1 0 1 0 0 0 1 0 1 3 157 443 01 02 04 32 0 0 0 32 32 1 (IF) IF AGC speed
For special conditions (descramblers with unstable black level) the vertical slicing level can be forced to 70% under all conditions by setting FSL = 1.
Gain FM demodulator
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IC DESCRIPTIONS AND INTERNAL BLOCK DIAGRAM · TDA9351 · STV9302 · TDA7056A · 24C08W6 · 74HC4053 · UC3842 TDA9351:
The various versions of the TDA935X/6X/8XPS/N2 series combine the functions of a TV signal processor together with a µ-Controller and US Closed Caption decoder. Most versions have a Teletext decoder on board. The Teletext decoder has an internal RAM memory for 1 or 10 page text. The ICs are intended to be used in economy television receivers with 90° and 110° picture tubes. The ICs have supply voltages of 8 V and 3.3 V and they are mounted in S-DIP envelope with 64 pins. 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 centre frequency and positive/negative overshoot ratio) and black stretching.
· · · ·
· 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 or multi-standard 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 the µ-Controller/Teletext decoder.
· Contrast reduction possibility during mixed-mode of OSD and Text signals.
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· · · · · · ·
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.
µ-Controller
· · · · · · · · · · · · · ·
80C51-controller core standard instruction set and timing. 1µs machine cycle. 32 - 128Kx8-bit late programmed ROM. 3 - 12Kx8-bit Auxiliary RAM (shared with Display and Acquisition). Interrupt controller for individual enable/disable with two level priority. Two 16-bit Timer/Counter registers. One 16 bit Timer with 8-bit Pre-scaler. WatchDog timer. Auxiliary RAM page pointer. 16-bit Data pointer. Stand-by, Idle and Power Down (PD) mode. 14 bits PWM for Voltage Synthesis Tuning. 8-bit A/D converter. 4 pins which can be programmed as general I/O pin, ADC input or PWM (6-bit) output.
Data Capture
· Text memory for 0, 1 or 10 pages. · In the 10 page versions inventory of transmitted Teletext pages stored in the Transmitted Page
Table (TPT) and Subtitle Page Table (SPT).
· Data Capture for US Closed Caption. · Data Capture for 525/625 line WST, VPS (PDC system A) and Wide Screen Signalling (WSS) bit
decoding.
· Automatic selection between 525 WST/625 WST. · Automatic selection between 625 WST/VPS on line 16 of VBI. · Real-time capture and decoding for WST Teletext in Hardware, to enable optimized-processor
throughput.
· · · · ·
Automatic detection of FASTEXT transmission. Real-time packet 26 engine in Hardware for processing accented, G2 and G3 characters. Signal quality detector for video and WST/VPS data types. Comprehensive teletext language coverage. Full Field and Vertical Blanking Interval (VBI) data capture of WST data.
Display
· Teletext and Enhanced OSD modes. · Features of level 1.5 WST and US Close Caption.
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Serial and Parallel Display Attributes. Single/Double/Quadruple Width and Height for characters. Scrolling of display region. Variable flash rate controlled by software. Enhanced display features including overlining, underlining and italics. Soft colours using CLUT with 4096 colour palette. Globally selectable scanlines per row (9/10/13/16) and character matrix [12x10, 12x13, 12x16 (VxH)].
· · · · · · · · · · · · · · · · ·
Fringing (Shadow) selectable from N-S-E-W direction. Fringe colour selectable. Meshing of defined area. Contrast reduction of defined area. Cursor. Special Graphics Characters with two planes, allowing our colours per character. 32 software redefinable On-Screen display characters. 4 WST Character sets (G0/G2) in single device (e.g. Latin, Cyrillic, Greek, Arabic). G1 Mosaic graphics, Limited G3 Line drawing characters. WST Character sets and Closed Caption Character set in single device.
PINNING SYMBOL P1.3/T1 P1.6/SCL P1.7/SDA P2.0/TPWM P3.0/ADC0 P3.1/ADC1 P3.2/ADC2 P3.3/ADC3 VSSC/P P0.5 P0.6 VSSA SECPLL VP2 DECDIG PH2LF PH1LF GND3 DECBG AVL/EWD VDRB VDRA IFIN1 IFIN2 IREF VSC
PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
DESCRIPTION port 1.3 or Counter/Timer 1 input port 1.6 or I2C-bus clock line port 1.7 or I2C-bus data line port 2.0 or Tuning PWM output port 3.0 or ADC0 input port 3.1 or ADC1 input port 3.2 or ADC2 input port 3.3 or ADC3 input digital ground for µ-Controller core and periphery port 0.5 (8 mA current sinking capability for direct drive of LEDs) port 0.6 (8 mA current sinking capability for direct drive of LEDs) analog ground of Teletext decoder and digital ground of TV-processor SECAM PLL decoupling 2nd supply voltage TV-processor (+8V) decoupling digital supply of TV-processor phase-2 filter phase-1 filter ground 3 for TV-processor bandgap decoupling Automatic Volume Levelling /East-West drive output vertical drive B output vertical drive A output IF input 1 IF input 2 reference current input vertical sawtooth capacitor 8
TUNERAGC AUDEEM/SIFIN1 DECSDEM/SIFIN2 GND2 SNDPLL/SIFAGC AVL/SNDIF/REF0/ AMOUT HOUT FBISO output AUDEXT/QSSO/AMOUT EHTO PLLIF IFVO/SVO VP1 CVBSINT GND1 CVBS/Y CHROMA AUDOUT/AMOUT INSSW2 R2/VIN G2/YIN B2/UIN BCLIN BLKIN RO GO BO VDDA VPE VDDC OSCGND XTALIN XTALOUT RESET VDDP P1.0/INT1 P1.1/T0 P1.2/INT0
27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64
tuner AGC output audio deemphasis or SIF input 1 decoupling sound demodulator or SIF input 2 ground 2 for TV processor narrow band PLL filter /AGC sound IF Automatic Volume Levelling/sound IF input/subcarrier reference output/AM output (non controlled) horizontal output flyback input/sandcastle external audio input/QSS intercarrier out/AM audio output (non controlled) EHT/overvoltage protection input IF-PLL loop filter IF video output/selected CVBS output main supply voltageTV-processor (+8V) internal CVBS input ground 1 for TV-processor external CVBS/Y input chrominance input (SVHS) audio output/AM audio output (volume controlled) 2nd RGB/YUV insertion input 2nd R input / V (R-Y) input 2nd G input / Y input 2nd B input / U (B-Y) input beam current limiter input / (V-guard input) black current input / (V-guard input) Red output Green output Blue output analog supply of Teletext decoder and digital supply of TV-processor (3.3 V) OTP Programming Voltage digital supply to core (3.3 V) oscillator ground supply crystal oscillator input crystal oscillator output reset digital supply to periphery (+3.3 V) port 1.0 or external interrupt 1 input port 1.1 or Counter/Timer 0 input port 1.2 or external interrupt 0 input
STV9302A:
The STV9302A is a vertical deflection booster designed for TV and monitor applications. This device, supplied with up to 35V, provides up to 2App output current to drive the vertical deflection yoke. The internal flyback generator delivers flyback voltages up to 70V. In double-supply applications, a stand-by state will be reached by stopping the (+) supply alone. Features:
· Power Amplifier · Flyback Generator · Output Current up to 2App
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· Thermal Protection · Stand-by Control
PINNING 1. Input (Inverting) 2. Supply Voltage 3. Flyback Generator 4. Ground Or Negative Supply 5. Output 6. Output Stage Supply 7. Input (Non Inverting)
TDA7056A:
The TDA7056A is a mono BTL output amplifier with DC volume control. It is designed for use in TV and monitors, but also suitable for battery-fed portable recorders and radios. Features:
· · · · · · · · · ·
DC volume control Few external components Mute mode Thermal Protection Short-circuit proof No switch-on and off clicks Good overall stability Low power consumption Low HF radiation ESD protected on all pins.
PINNING 1. Not connected, n.c. 2. Positive supply voltage, VP 3. Voltage input, VI 4. Signal ground, GND1 5. DC volume control, VC 6. Positive output, OUT+ 7. Power ground, GND2 8. Negative output, OUT9. Not connected, n.c.
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24C08W6:
The M24C08W6 is a series of 2-wire, low power 8Kbit EEPROM with a wide operating range. It is organized as 1K-word X 8-bit. It is capable of page write and sequential read. Features:
· · · · · · · · · ·
Two Wire I2C Serial Interface Supports 400kHz Protocol. Single Supply Voltage: 2.5V to 5.5V. Write Control Input. BYTE and PAGE WRITE (up to 16 Bytes). RANDOM and SEQUENTIAL READ Modes. Self-Timed Programming Cycle. Automatic Address Incrementing. Enhanced ESD/Latch-Up Behavior. More than 1 Million Erase/Write Cycles. More than 40 Year Data Retention.
PINNING 1. Connected to ground, A0 2. Connected to ground, A1 3. Connected to ground, A2 4. Connected to ground, A3 5. Serial data input/output, SDA 6. Serial clock input, SCL 7. Write protection Pin, WP : Protection valid - Connected to VCC - Connected to Ground : Protection invalid 8. Power Supply, VCC
74HC4053:
The 74HC/HCT4053 are high-speed Si-gate CMOS devices and are pin compatible with the "4053" of the "4000B" series. They are specified in compliance with JEDEC standard no. 7A. The 74HC/HCT4053 are triple 2-channel analog multiplexers/demultiplexers with a common enable input ). Each multiplexer/demultiplexer has two independent inputs/outputs (nY0 and nY1), a common input/output (nZ) and three digital select inputs (S1 to S3). With LOW, one of the two switches is selected (low impedance ON-state) by S1 to S3. With HIGH, all switches are in the high impedance OFF-state, independent of S1 to S3. VCC and GND are the supply voltage pins for the digital control inputs (S1, to S3, and ). The VCC to GND ranges are 2.0 to 10.0 V for HC and 4.5 to 5.5 V for HCT. The analog inputs/outputs (nY0 and nY1, and nZ) can swing between VCC as a positive limit and Vee as a negative limit. VCC -VEE may not exceed 10.0 V. For operation as a digital multiplexer/demultiplexer, VEE is connected to GND (typically ground).
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Features:
· Low "ON" resistance:
80 (typ.) at VCC-VEE=4.5 V, 70 (typ.) at VCC-VEE=6.0 V, 60 (typ.) at VCC-VEE=9.0 V.
· Logic level translation: to enable 5 V logic to communicate with 5V analog signals. · Typical "break before make" built in. · Output capability: non-standard.
PINNING PIN 2, 1 5, 3 6 7 8 11, 10, 9 12, 13 14, 15, 4 16
SYMBOL 2Y0 to, 2Y1 3Y0 to, 3Y1 VEE GND S1 to S3 1Y0, 1Y1 1Z to 3Z VCC
NAME AND FUNCTION independent inputs/outputs independent inputs/outputs enable input (active LOW) negative supply voltage ground (0 V) select inputs independent inputs/outputs common inputs/outputs positive supply voltage
UC3842:
The UC3842 provides all the essential features necessary to the operation of the basic current mode controller. PINNING 1. Error amplifier output. 2. Error amplifier inverting input. 3. Current sense comparator. 4. Timing network, RT CT. 5. Device ground. 6. Switching drive output. 7. Device supply voltage input. 8. Voltage reference, 5.0V.
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