Hitachi C1426R Schematic

CAUTION:

Before servicing this chassis, it is important that the service technician read the “Safety
Precautions” and “Product Safety Notices” in this service manual.

ATTENTION:

Avant d’effectuer l’entretien du châassis, le technicien doit lire les «Précautions de sécurité»
et les «Notices de sécurité du produit» présentés dans le présent manuel.

VORSICHT:

Vor Öffnen des Gehäuses hat der Service-Ingenieur die „Sicherheitshinweise“ und „Hinweise
zur Produktsicherheit“ in diesem Wartungshandbuch zu lesen.

SERVICE MANUAL
MANUEL D'ENTRETIEN
WARTUNGSHANDBUCH

Data contained within this Service
manual is subject to alteration for
improvement.

Les données fournies dans le présent
manuel d’entretien peuvent faire l’objet
de modifications en vue de perfectionner
le produit.

Die in diesem Wartungshandbuch
enthaltenen Spezifikationen können sich
zwecks Verbesserungen ändern.

«MODEL NAMES»

SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT

Colour Television

August 2003

No. 0111

C1426R

CL1426T
CP1426T

1

CONTENTS

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

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

1 INTRODUCTION ...................................................................................................................................... 2

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

2.1 Vision IF Amplifier3 .......................................................................................................................... 3

2.2 QSS Sound Circuit (QSS Versions) ................................................................................................. 3

2.3 AM Demodulator .............................................................................................................................. 3

2.4 FM Demodulator and Audio Amplifier (Mono Versions): .................................................................... 3

2.5 Video Switching ............................................................................................................................... 3

2.6 Synchronization Circuit .................................................................................................................... 3

2.7 Chroma and Luminance Processing: ................................................................................................ 4

2.8 RGB output circuýt ........................................................................................................................... 4

2.9 µ-Controller ...................................................................................................................................... 4

3 TUNER ................................................................................................................................................... 5

4 SOUND OUTPUT STAGE TDA2822 ........................................................................................................ 5

5 VERTICAL OUTPUT STAGE WITH TDA8174A ........................................................................................ 5

6 POWER SUPPLY (SMPS) ..................................................................................................................... 5

7 DISCRETE VIDEO AMPLIFIER ............................................................................................................... 5

8 SERIAL ACCESS CMOS 8K EEPROM 24C08 ....................................................................................... 6

9 SAW FILTERS ........................................................................................................................................ 6

10 IC DESCRIPTIONS AND INTERNAL BLOCK DIAGRAM ...................................................................... 6

10.1 ST92195 ....................................................................................................................................... 6-7

10.2 STV224X Video processor: .............................................................................................................. 7

10.3 UV1315, UV1316, UV1336 ............................................................................................................ 8-9

10.4 TDA2822.......................................................................................................................................... 9

10.5 TDA8174AW .................................................................................................................................... 9

10.6 UC3842/3....................................................................................................................................... 10

10.7 E²Eprom 24CO8 ............................................................................................................................ 10

Saw filters list ................................................................................................................................11

11 GENERAL BLOCK DIAGRAM ........................................................................................................... 12

12 TITANIUM TELETEXT - Language Groups ........................................................................................... 13

13 MANUAL ADJUSTMENT PROCEDURE ............................................................................................... 14

14 SERVÝCE ADJUSTMENTS ............................................................................................................15-16

15 OPTION LIST..................................................................................................................................... 17

15.1 OP1  Peripheral Options .............................................................................................................. 17

15.2 OP2  Reception Standard Options ............................................................................................... 17

15.3 OP3  Video Options ..................................................................................................................... 17

15.4 OP4  TV Features ........................................................................................................................ 18

15.5 OP5  Channel Tables ................................................................................................................... 18

15.6 TX1  Teletext Options ................................................................................................................... 18

16. TUNER SETTING .............................................................................................................................. 19

17 CIRCUIT DIAGRAM of VIDEO PROCESSOR..................................................................................... 20

CIRCUIT DIAGRAM of SMPS ............................................................................................................ 21

CIRCUIT DIAGRAM of MICRO CONTROLLER ................................................................................... 22

CIRCUIT DIAGRAM of VIDEO............................................................................................................ 23

CIRCUIT DIAGRAM of DEFLECTION ................................................................................................. 24

CIRCUIT DIAGRAM of CRT................................................................................................................ 25

18 WAVEFORMS ...................................................................................................................................... 20

2

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.

- When servicing this TV, check that the EHT does not exceed 26kV.

TV set switched off:

Make short-circuit between HV-CRT clip and CRT ground layer.
Short C808 before changing IC841 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

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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

1 INTRODUCTION

This is a 90° chassis capable of driving 14 tubes at the appropriate currents. The chassis is capable of operating in PAL,
SECAM and NTSC standards. The sound system is capable of giving 3 watts RMS output into a load of 16 ohms. One page and
US Closed Caption is also provided. The chassis is equipped with a 21 pin Eu-Scart connector.

3

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 Amplifier3

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.

2.3. AM DEMODULATOR

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

2.4 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.
For the 90° types the capacitor is connected to the EW output pin (pin 20). When the AVL is active it automatically
stabilizes the audio output signal to a certain level.

2.5 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 from FAV, and the third one is used for internal video. The
selection between both external video inputs signals is realized by means of software switches.

2.6 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).

4

2.7 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 I2C bus.
NTSC tint, and auto flesh are controlled through I2C 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, auto-aligned via a master filter
phase locked loop.

2.8 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 I2C adjustments,

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

- Blanking control and RGB output stages.

2.9 µ-Controller

The ST92195 is the micro-controller, which is required for a color TV receiver. ST92195D1 is the version with one 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

5

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 PALM/N, NTSC M applications UV 1336 is used as the PLL tuner. UV
1315 (VHF/UHF) is used as a VST Tuner.

Channel coverage of UV1316:

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(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:

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

Channel Coverage of UV1315:

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(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)

4 SOUND OUTPUT STAGE TDA2822

TDA2822 is used as the AF output amplifier. It is supplied by +12VDC coming from a separate winding in the SMPS
transformer. An output power of 3W (THD=10%) can be delivered into an 16 ohm load.

5 VERTICAL OUTPUT STAGE WITH TDA8174A

The TDA8174A is a power amplifier circuit for use in 90° and 110° colour deflection systems for 25 to 200 Hz field frequen­cies, and for 4 : 3 and 16 : 9 picture tubes.

6 POWER SUPPLY (SMPS)

The DC voltages required at various parts of the chassis are provided by an SMPS transformer controlled by the IC UC3842/
3 which is designed for driving, controlling and protecting switching transistor of SMPS. The transformer produces 115V for
FBT input, ±12V for audio output IC, S+5V and 8V for ST92195.

7 DISCRETE VIDEO AMPLIFIER

Three high voltage, high frequency transistor is used for RGB amplifier. This application works on fixed AC and DC gains.

6

8 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.

9 SAW FILTERS

Saw filter type : Model:
G1975M : PAL B/G MONO
K2966M : PAL SECAM B/G/D/K/I MONO
J1981 : PAL-I MONO
K2966M : PAL-SECAM B/G/D/K/I/I MONO
K2962M : PAL-SECAM B/G/D/K/I/L/L MONO
L9653 : Secam L/L audio
M1962M : PAL M/N NTSC M MONO

IC DESCRIPTIONS AND INTERNAL BLOCK DIAGRAM

· ST92195

· STV224X

· TUNER (UV1315, UV1316, UV1336)

· TDA2822

· TDA8174A

· UC3842/3

· 24C08

· SAW FILTERS

G1975M, K2966M, K2962M, M1962M

10.1 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
sys-tem 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.

7

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10.2 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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8

10.3 UV1315, UV1316, UV1336

General description of UV1315:

The UV1315 tuner belongs to the UV 1300 family of tuners, which are designed to meet a wide range of applications. It is a
combined VHF, UHF tuner suitable for CCIR systems B/G, H, L, L, I and I.

Features of UV1315:

· Member of the UV1300 family small sized UHF/VHF tuners

· Systems CCIR:B/G, H, L, L, I and I; OIRT:D/K

· Voltage synthesized tuning (VST)

· Off-air channels, S-cable channels and Hyper-band

· Standardized mechanical dimensions and pinning

PINNING PIN VALUE

1. Gain control voltage (AGC) : 4.0V, Max:4.5V

2. Tuning voltage

3. High band switch : 5V, Min:4.75V, Max:5.5V

4. Mid band switch : 5V, Min:4.75V, Max:5.5V

5. Low band switch : 5V, Min:4.75V, Max:5.5V

6. Supply voltage : 5V, Min:4.75V, Max:5.5V

7. Not connected

8. Not connected

9. Not connected

10.Symmetrical IF output 1

11. Symmetrical IF output 2

Band switching table:

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General description of UV1316:

The UV1316 tuner belongs to the UV 1300 family of tuners, which are designed to meet a wide range of applications. It is a
combined VHF, UHF tuner suitable for CCIR systems B/G, H, L, L, I and I.

Features of UV1316:

· Member of the UV1300 family small sized UHF/VHF tuners

· Systems CCIR: B/G, H, L, L, I and I; OIRT: D/K

· Digitally controlled (PLL) tuning via I²C-bus

· Off-air channels, S-cable channels and Hyper-band

· World standardized mechanical dimensions and world standard pinning

· Complies to CENELEC EN55020 and EN55013

PINNING PIN VALUE

1. Gain control voltage (AGC) : 4.0V, Max:4.5V

2. Tuning voltage

3. I²C-bus address select : Max:5.5V

4. I²C-bus serial clock : Min:-0.3V, Max:5.5V

5. I²C-bus serial data : Min:-0.3V, Max:5.5V

6. Not connected

7. PLL supply voltage : 5.0V, Min:4.75V, Max:5.5V

8. ADC input

9. Tuner supply voltage : 33V, Min:30V, Max:35V

10. Symmetrical IF output 1

11. Symmetrical IF output 2