VESTEL 11AK37 Service Manual

CONTENTS

SAFETY PRECAUTIONS: ....................................................................................................................................... 2

TV set switched off................................................................................................................................................2

Measurements ........................................................................................................................................................2

PERI-TV SOCKET....................................................................................................................................................2

SCART 1...............................................................................................................................................................2

SCART 2...............................................................................................................................................................2

1. INTRODUCTION ................................................................................................................................................. 3

2. SMALL SIGNAL PART WITH STV2248 ........................................................................................................3

2.1 Vision IF amplifier........................................................................................................................................... 3

2.2 QSS Sound circuit (QSS versions).................................................................................................................... 3

2.3 FM demodulator and audio amplifier (mono versions)......................................................................................3

2.4 Video switch....................................................................................................................................................4

2.5 Synchronisation circuit.....................................................................................................................................4

2.6 Chroma and luminance processing...................................................................................................................4

2.7 RGB output circuit...........................................................................................................................................5

2.8 µ-Controller ................................................................................................ .....................................................5

3. TUNER ................................ .................................................................................................................................6

4- MULTISTANDARD SOUND PROCESSOR .........................................................................................................7

5. SOUND OUTPUT STAGE TDA7269A .................................................................................................................7

6. VERTICAL OUTPUT STAGE WITH STV9306.................................................................................................... 7

7. VIDEO OUTPUT AMPLIFIER STV5112..............................................................................................................7

8. POWER SUPPLY (SMPS).....................................................................................................................................7

9. POWER FACTOR CORRECTION................................ ........................................................................................7

10. SERIAL ACCESS CMOS 8K EEPROM 24C08................................................................................................ ...7

11. CLASS AB STEREO HEADPHONE DRIVER TDA1308 ...................................................................................7

12. CLASS AB MONO SUBWOOFER DRIVER TDA7261......................................................................................7

13. SAW FILTERS.................................................................................................................................................... 7

14. IC DESCRIPTIONS AND INTERNAL BLOCK DIAGRAM................................ ...............................................8

ST92195.......................................................................................................................................................8

•

STV224X.................................................................................................................................................... 10

•

UV1315, UV1316, UV1336........................................................................................................................11

•

TDA7269A.................................................................................................................................................12

•

STV9306 ................................ ....................................................................................................................13

•

STV5112 ................................ ....................................................................................................................14

•

MC44608 ....................................................................................................................................................15

•

MSP 34XXG ...............................................................................................................................................16

•

24C08.........................................................................................................................................................17

•

TDA1308 ....................................................................................................................................................17

•

TDA7261 ....................................................................................................................................................17

•

SAW FILTERS...........................................................................................................................................18

•

GENERAL BLOCK DIAGRAM of 11AK37 ...........................................................................................................19

Service menu ..........................................................................................................................................................20

Options ....................................................................................................................................................................21

Languages ................................ ...............................................................................................................................24

DO NOT CHANGE ANY MODULE UNLESS THE SET IS SWITCHED OFF

The mains supply part of the switch mode power supply’s transformer is live. Use an isolating transformer. The receiver complies with the safety requirements.

SAFETY PRECAUTIONS:

The service of this TV set must be carried out by qualified persons only. Components marked with the warning symbol on the circuit diagram are critical for safety and must only be replaced with an identical component.

- Power resistor and fused resistors must be mounted in an identical manner to the original

component.

TV set switched off:

Make short-circuit between HV-CRT clip and CRT ground layer. Short C809 before changing IC800 and IC801 or other components in primary side of the SMPS part.

Measurements:

Voltage readings and oscilloscope traces are measured under the following conditions: Antenna signal’s level is 60dB at the color bar pattern from the TV pattern generator. (100% white, 75% color saturation) Brightness, contrast, and color are adjusted for normal picture performance. Mains supply, 220VAC, 50Hz.

PERI-TV SOCKET

SCART 1 PINING

1 Audio right output 0.5Vrms / 1K 2 Audio right input 0.5Vrms / 10K 3 Audio left output 0.5Vrms / 1K 4 Ground AF 5 Ground Blue 6 Audio left input 0.5Vrms / 10K 7 Blue input 0.7Vpp / 75ohm 8 AV switching input 0-12VDC /10K 9 Ground Green 10 11 Green input 0.7Vpp / 75ohm 12 13 Ground Red 14 Ground Blanking 15 Red input 0.7Vpp / 75ohm 16 Blanking input 0-0.4VDC, 1-3VDC / 75 Ohm 17 Ground CVBS output 18 Ground CVBS input 19 CVBS output 1Vpp / 75ohm 20 CVBS input 1Vpp / 75ohm 21 Ground

SCART 2 PINING

1 Audio right output 0.5Vrms / 1K 2 Audio right input 0.5Vrms / 10K 3 Audio left output 0.5Vrms / 1K 4 Ground AF 5 Ground Blue 6 Audio left input 0.5Vrms / 10K 7 Blue input 8 AV switching input 0-12VDC /10K 9 Ground Green 10 11 12 13 Ground Red 14 Ground Blanking 15 16 17 Ground CVBS output 18 Ground CVBS input 19 CVBS output 1Vpp / 75ohm 20 CVBS input 1Vpp / 75ohm 21 Ground

1. INTRODUCTION

11AK37 is a 110° chassis capable of driving 25”, 28”, 29”, 33” 4:3 and 28”, 32” 16:9 tubes at the appropriate currents. The chassis is capable of operating in PAL, SECAM and NTSC standards and multiple transmission standards as B/G, D/K, I/I’, and L/L´. standards. The sound system is capable of giving 12 watts RMS output into a load of 8 ohms. One page, 7 page SIMPLETEXT, TOPTEXT, FASTTEXT and US Closed Caption is also provided. The chassis is equipped with a double-deck 42 pin scart connector for AV input/output, front-AV input, one back-AV output, one SVHS, one headphone and one subwoofer.

2. SMALL SIGNAL PART WITH STV2248:

STV2248 video processor is essential for realizing all small signal functions for a color TV receiver.

2.1 Vision IF amplifier

The vision IF amplifier can demodulate signals with positive and negative modulation. The PLL demodulator is completely alignment-free. Although the VCO (Toko-coil) of the PLL circuit is external, yet the frequency is fixed to the required value by the original manufacturer thus the Toko-coil does not need to be adjusted manually. The setting of the various frequencies (38.9 or

45.75 MHz) can be made via changing the coil itself.

2.2 QSS Sound circuit (QSS versions)

The sound IF amplifier is similar to the vision IF amplifier and has an external AGC de-coupling capacitor. The single reference QSS mixer is realised by a multiplier. In this multiplier the SIF signal is converted to the inter-carrier frequency by mixing it with the regenerated picture carrier from the VCO. The mixer output signal is supplied to the output via a high-pass filter for attenuation of the residual video signals. With this system a high performance hi-fi stereo sound processing can be achieved. The AM sound demodulator is realised by a multiplier. The modulated sound IF signal is multiplied in phase with the limited SIF signal. The demodulator output signal is supplied to the output via a low-pass filter for attenuation of the carrier harmonics. The AM signal is supplied to the output via the volume control.

The AM demodulated signal results from multiplying the input signal by itself, it is available on AM/FM output.

2.3 FM demodulator and audio amplifier (mono versions):

The FM demodulator is realized as narrow-band PLL with external loop filter, which provides the necessary selectivity without using an external band-pass filter. To obtain a good selectivity a linear phase detector and constant input signal amplitude are required. For this reason the inter-carrier signal is internally supplied to the demodulator via a gain controlled amplifier and AGC circuit. The nominal frequency of the demodulator is tuned to the required frequency (4.5/5.5/6.0/6.5 MHz) by means of a calibration circuit that uses the clock frequency of the µ-controller/Teletext decoder as a reference. The setting to the wanted frequency is realized by means of the software. It can be read whether the PLL frequency is inside or outside the window and whether the PLL is in lock or not. With this information it is possible to make an automatic search system for the incoming sound frequency. This is realized by means of a software loop that alternate the demodulator to various frequencies, then select the frequency on which a lock condition has been found. De-emphasis output signal amplitude is independent of the TV standard and has the same value for a frequency deviation of ±25 kHz at the 4.5 MHz standard and for a deviation of ±50 kHz for the other standards. When the IF circuit is switched to positive modulation the internal signal on de-emphasis pin is automatically muted. The audio control circuit contains an audio switch and volume control.

In the mono inter-carrier sound versions the Automatic Volume Leveling (AVL) function can be activated. The pin to which the external capacitor has to be connected depends on the IC version.

2.4 Video switching

The video processor (STV2248C) has three CVBS inputs and two RGB inputs. The first CVBS input is used for external CVBS from SCART 1, the second is used for either CVBS or Y/C from either SCART2 or BAV/FAV or SVHS, and the third one is used for internal video. The selection between both external video inputs signals is realized by means of software and hardware switches.

2.5 Synchronization circuit

The video processor (STV224X) performs the horizontal and vertical processing. The external horizontal deflection circuit is controlled via the Horizontal output pulse (HOUT). The vertical scanning is performed through an external ramp generator and a vertical power amplifier IC controlled by the Vertical output pulse (VOUT). The main components of the deflection circuit are:

• PLL1: the first phase locked loop that locks the internal line frequency reference on the

CVBS input signal. It is composed of an integrated VCO (12 MHz) that requires the chroma reference frequency (4.43MHz or 3.58MHz crystal oscillator reference signal), a divider by 768, a line decoder, and a phase comparator.

• PLL2: The second phase locked loop that controls the phase of the horizontal output

(Compensation of horizontal deflection transistor storage time variation). Also the horizontal position adjustment is also performed in PLL2.

• A vertical pulse extractor.

• A vertical countdown system to generate all vertical windows (vertical synchronization

window, frame blanking pulses, 50/60Hz identification window...).

• Automatic identification of 50/60Hz scanning.

• PLL1 time constant control.

• Noise detector, video identification circuits, and horizontal coincidence detector.

• Vertical output stage including de-interlace function, vertical position control.

• Vertical amplitude control voltage output (combined with chroma reference output and

Xtal 1 indication).

2.6 Chroma and luminance processing:

The chroma decoder is able to demodulate PAL, NTSC and SECAM signals. The decoder dedicated to PAL and NTSC sub-carrier is based on a synchronous demodulator, and an Xtal PLL locked on the phase reference signal (burst). The SECAM demodulation is based on a PLL with automatic calibration loop. The color standard identification is based on the burst recognition. Automatic and forced modes can be selected through the I 2C bus. NTSC tint, and auto flesh are controlled through I 2C bus. Xtal PLL can handle up to 3 crystals to work in PAL M, PAL N and NTSC M for South America. ACC an ACC overload control the chroma sub-carrier amplitude within 26dB range. Both ACC s are based on digital systems and do not need external capacitor. All chroma filters are fully integrated and tuned via a PLL locked on Xtal VCO signal. A second PLL is used for accurate fine-tuning of the SECAM bell filter. This tuning is achieved during the frame blanking. An external capacitor memorizes the bell filter tuning voltage. A base-band chroma delay-line rebuilds the missing color line in SECAM and removes transmission phase errors in PAL. The base-band chroma delay line is clocked with 6MHz signal provided by the horizontal scanning VCO.

The luminance processor is composed of a chroma trap filter, a luminance delay line, a peaking function with noise coring feature, a black stretch circuit. Trap filter and luminance delay lines are achieved with the use of bi-quad integrated filters, autoaligned via a master filter phase locked loop.

2.7 RGB output circuit:

The video processor performs the R, G, B processing. There are three sources:

1. Y,U,V inputs (coming from luma part (Y output), and chroma decoder outputs (R-Y, B-Y

outputs).

2. External R,G,B inputs from SCART (converted internally in Y,U,V), with also the possibility to

input YUV signals from a DVD player, (YUV specification is Y=0.7 V PP , U= 0.7 V PP , V =

0.7V PP for 100% color bar).

3. Internal R,G,B inputs (for OSD and Teletext display)

The main functions of the video part are:

Y,U,V inputs with integrated clamp loop, allowing a DC link with YUV outputs,

•

• External RGB inputs (RGB to YUV conversion), or direct YUV inputs,

• Y,U,V switches,

• Contrast, saturation, brightness controls,

YUV to RGB matrix,

•

• OSD RGB input stages (with contrast control),

• RGB switches,

APR function,

•

DC adjustment of red and green channels,

•

• Drive adjustments (R, G, B gain),

• Digital automatic cut-off loop control,

Manual cut-off capability with I 2C adjustments,

•

• Half tone, oversize blanking, external insertion detection, blue screen,

• Blanking control and RGB output stages.

2.8 µ-Controller

The ST92195 is the micro-controller, which is required for a color TV receiver. ST92195D1 is the version with one page Teletext and ST92195D7 is the one with 7 page Teletext. The IC has the supply voltages of 5 V and they are mounted in PSDIP package with 56 pins. µ-Controller has the following features

Display of the program number, channel number, TV Standard, analogue values, sleep timer,

•

parental control and mute is done by OSD

• Single LED for standby and on mode indication

System configuration with service mode

•

• 3 level logic output for SECAM and Tuner band switching

3. TUNER

Either a PLL or a VST tuner is used as a tuner.

UV1316 (VHF/UHF) is used as a PLL tuner. For only PAL M/N, NTSC M applications UV 1336

RANGE (MHz)

is used as the PLL tuner. UV 1315 (VHF/UHF) is used as a VST Tuner.

Channel coverage of UV1316:

BAND

OFF-AIR CHANNELS CHANNELS FREQUENCY RANGE

CABLE CHANNELS CHANNELS FREQUENCY RANGE (MHz)

(MHz)

Low Band E2 to C

48.25 to 82.25 (1)

S01 to S08 69.25 to 154.25 Mid Band E5 to E12 175.25 to 224.25 S09 to S38 161.25 to 439.25 High Band E21 to E69 471.25 to 855.25

S39 to S41 447.25 to 463.25

(2)

(1). Enough margin is available to tune down to 45.25 MHz. (2). Enough margin is available to tune up to 863.25 MHz.

Noise Typical Max. Gain Min. Typical Max.

Low band : 5dB 9dB All channels : 38dB 44dB 52dB Mid band : 5dB 9dB Gain Taper (of-air channels): 8dB High band : 6dB 9dB

Channel Coverage UV1336:

BAND

CHANNELS FREQUENCY RANGE (MHz)

Low Band 2 to D 55.25 to 139.25 Mid Band E to PP 145.25 to 391.25 High Band QQ to 69 397.25 to 801.25

Noise is typically 6dB for all channels. Gain is minimum 38dB and maximum 50dB for all channels.

Channel Coverage of UV1315:

BAND OFF-AIR CHANNELS CABLE CHANNELS CHANNELS FREQUENCY

CHANNELS FREQUENCY

Low Band E2 to C 48.25 to 82.25 Mid Band E5 to E12 175.25 to 224.25 S11 to S39 231.25 to 447.25 High Band E21 to E69

(1). Enough margin is available to tune down to 45.25 MHz. (2). Enough margin is available to tune up to 863.25 MHz.

Noise Typ. Max. Gain Min. Typ. Max.

Low band 6dB 9dB All Channels 38dB 44dB 50dB Mid band 6dB 10dB Gain Taper 8dB High band 6dB 11dB (off-air channels)

S01 to S10 69.25 to 168.25

(1)

471.25 to 855.25 (2)

S40 to S41 455.25 to 463.25

4. MULTISTANDARD SOUND PROCESSOR

The MSP 34xxG is designed to perform demodulation of FM or AM-Mono TV sound. Three kinds of MSP’s are used: MSP 3400G,MSP 3410G and MSP 3411G. The MSP 3400G is fully pin and software-compatible to the MSP 3410G, but is not able to decode NICAM. It is also compatible to the MSP 3411G,sound processor IC with virtual dolby sound.

5. SOUND OUTPUT STAGETDA7269A

The TDA7269A is a class AB dual Audio power amplifier, specially designed for high quality sound applications as Hi-Fi music centers and TV sets. It is supplied by ±12VDC coming from two separate windings in the SMPS transformer.It gives 2x14W(THD=10%) output power into an 8ohm load.

6. VERTICAL OUTPUT STAGE WITH STV9306

The STV9306 is a fully I2C controlled vertical deflection IC designed for use in 110°, 4/3 or 16/9 CRT applications. It integrates both the vertical deflection and E/W correction circuitries necessary in design of a 110° chassis.

7. VIDEO OUTPUT AMPLIFIER STV5112

The STV5112 consists of three monolithic video output amplifiers. The amplifier can be seen as an operational amplifier with negative feedback. The advantage of negative feedback is that the amplifier characteristics do not play an important role up to certain frequencies. The internal flash diodes protect the amplifiers against flash over in the picture tube. The only protections required at the cathode outputs are a flash resistor and a spark gap. Furthermore, the device has a high voltage power supply (VDD) and a low voltage one (VCC).

8. POWER SUPPLY (SMPS)

The DC voltages required at various parts of the chassis are provided by an SMPS transformer controlled by the IC MC44608 which is designed for driving, controlling and protecting switching transistor of SMPS. The transformer produces 150V for FBT input, ±12V for audio output IC, +5V and +8V for ST92195.

9. POWER FACTOR CORRECTION

Passive components are used for the solution of power factor correction.

10. SERIAL ACCESS CMOS 8K EEPROM 24C08

The 24C08 is a 8Kbit electrically erasable programmable memory (EEPROM), organized as 4 blocks of 256*08 bits. The memory is compatible with the I²C standard, two wire serial interface which uses a bi-directional data bus and serial clock.

11. CLASS AB STEREO HEADPHONE DRIVER TDA1308

The TDA1308 is an integrated class AB stereo headphone driver contained in a DIP8 plastic package.

12. CLASS AB MONO SUBWOOFER DRIVER TDA7261

The TDA7261 is a class AB dual Audio power amplifier, specially designed for high quality sound applications in mono TV chassis. It is supplied by ±12VDC.

13. SAW FILTERS Saw filter type: Model: G1975M: PAL B/G MONO K2966M: PAL SECAM B/G/D/K/I MONO J1981 : PAL-I MONO K2958M: PAL-SECAM B/G-D/K (38) MONO K2962M: PAL-SECAM B/G/D/K/I/L/L’ MONO L9653M: SECAM L/L’ AM MONO (AUDIO IF) G3967M: PAL-SECAM B/G STEREO (VIDEO IF) G9353M: PAL-SECAM B/G STEREO (AUDIO IF) K3958M: PAL-SECAM B/G/D/K/I/L/L’ STEREO (VIDEO IF) K9356M: PAL-SECAM B/G/D/K/I STEREO (AUDIO IF) K9656M: PAL-SECAM B/G/D/K/I/L/L’ STEREO (AUDIO IF) K3958M: PAL I NICAM (VIDEO IF) K9356M: PAL I NICAM (AUDIO IF) M1962M: PAL M/N NTSC M MONO M3953M: PAL M/N NTSC M STEREO (VIDEO IF) M9370M: PAL M/N NTSC M STEREO (AUDIO IF)

IC DESCRIPTIONS AND INTERNAL BLOCK DIAGRAM

ST92195

•

• STV224X

• TUNER (UV1315, UV1316, UV1336)

• TDA7269A

STV9306

•

• STV5112

• MC44608

• MSP 34XXG

24C08

•

• TDA1308

• SAW FILTERS

G1975M, K2966M, K2962M, L9653M, G3962M, G9353M, K3958M, K9356M, K9656M, K6263K, K9652M,M1962M, M3953M, M9370M

ST92195

The ST92195 is a member of the ST9+ family of micro-controllers, completely developed and produced by SGS-THOMSON Microelectronics using a proprietary n-well HCMOS process. The nucleus of the ST92195 is the advanced Core, which includes the Central Processing Unit (CPU), the ALU, the Register File and the interrupt controller. The Core has independent memory and register buses to add to the efficiency of the code. A set of on-chip peripherals form a complete system for TV set and VCR applications:

– Voltage Synthesis – VPS/WSS Slicer – Teletext Slicer – Teletext Display RAM – OSD Additional peripherals include a watchdog timer , a serial peripheral interface (SPI), a 16-bit timer and an A/D converter.

STV224X Video processor:

The STV2246/2247/2248 are fully bus controlled ICs for TV including PIF, SIF, luma, chroma and deflection processing. Used with a vertical frame booster (TDA1771 or TDA8174 for 90° chassis, STV9306 for 110° chassis), they allow the design of multi-standard (BGDKIMNLL, PAL/ SECAM/NTSC) sets with very few external components and no manual adjustments.

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