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SERVICE MANUAL




I2C-Bus Chassis
28''CTV
SM-2 Chassis 28" Service Manual
I2C Bus Chassis Service Manual




CONTENTS
PAGE
1. Main characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Recommendation for service repairs . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
3. Handling of mos chip components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
4. X-Ray radiation precaution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
5. Chassis Adjustments procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
6. Specification of the connector (Euroscart) . . . . . . . . . . . . . . . . . . . . . . .7
7. Component descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
8. Exploded view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
9. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
10. Fault tracing diagram -power supply . . . . . . . . . . . . . . . . . . . . . . . . . . .11
11. Power supply circuit diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
12. Troubleshooting guide for main pcb . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
13. General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
14. Circuit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
15. Description of the integrated circuits . . . . . . . . . . . . . . . . . . . . . . . . . . .19
M27C1001 (UV eprom and OTP eprom) . . . . . . . . . . . . . . . . . . . . .21
STV2118-B (Bus controlled Pal/Secam/
NTSC TV processor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
STV2145 (I2C bus controlled east-west and
vertical interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
STV2180 (Base band chroma delay line) . . . . . . . . . . . . . . . . . .27
STV6400 (Double scart interface) . . . . . . . . . . . . . . . . . . . . . . . . .29
TEA5101B (RGB high voltage video amplifier) . . . . . . . . . . . . . . . .31
TDA8172 (TV vertical deflection output circuit) . . . . . . . . . . . . . .33
ST24/25C8 (Serial 8K Eeprom) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
TDA4470-B (Multistandard video - IF and Quasi
parallel sound processing) . . . . . . . . . . . . . . . . . . . . . . .36
TDA4472-A (Video - IF with FPLL demodulation
and Quasi parallel sound processing)) . . . . . . . . . . . . .39
U2860B-B (Dual channel FM sound demodulator) . . . . . . . . . . . .42
SAA7283 (Terrestrial digital sound decoder) . . . . . . . . . . . . . . . . .44
TDA9840 (TV and VTR stereo / dual sound processor) . . . . . . . . .48
TDA9860 (Universal Hi Fi audio processor) . . . . . . . . . . . . . . . . . .51
TDA2616Q (Hi Fi audio power amplifiers with mute) . . . . . . . . . . . .54
MC44604 (High safety with stand-by burst mode,
greenline PWM controller . . . . . . . . . . . . . . . . . . . . . . . .56
UV1316 MK2 (VHF / UHF television tuner . . . . . . . . . . . . . . . . . . . . . . .58
TL431 (programmable voltage reference) . . . . . . . . . . . . . . .60
16. Chassis Replacement parts list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61



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I2C Bus Chassis Service Manual




1. MAIN CHARACTERISTICS
GENERAL FEATURES
No of menu languages 9 Fast teletext Yes
On screen displays Yes Top teletext Opt.
Voltage synthesis tuning No Text capturing Yes
Frequency synthesis tuning Yes Program storage location 99+3
User friendly menu Yes Help menu Yes
Sleep timer Yes Infrared remote control Yes
Channel Searching system ATS Multi-functional R.C. Yes
Independent clock No Teletext synchronous clock Yes
Child lock Yes Auto shut off Yes
Top Ten list Yes No of teletext formats 3
Panorama mode zooming Yes Horizontal comp. & exp. Yes
Vertical comp. & exp. Yes 33'' tube Opt.

RECEPTION SYSTEM
PAL B/G Opt. SECAM B/G Opt. PAL L/L' Opt.
SECAM L/L' Opt. PAL D/K Opt. SECAM D/K Opt.
PAL I Opt. SECAM I Opt. NTSC PLAYBACK Opt.
NTSC M No NTSC B/G No S-BAND (S1-S41) Yes
PAL N No PAL M No S-VHS Yes
16:9 Tube Opt. Hyperband Reception Yes


SOUND FEATURES
Mono only No Bass control Yes
Treble control Yes Balance control Yes
NICAM stereo Opt. A2 GERMAN stereo Opt.
NICAM+A2 GERMAN stereo Opt. Dolby surround sound Opt.
Incredible sound Opt. Auto volume limiting Yes
Headphone output Yes Central output Opt.
Built in speaker 2 Surround outputs 2
3-D phonic Opt. Equalizer (5 Band) Opt.

EXTERNAL INTERFACES
75 Ohm antenna >nput Yes Headphone terminals Yes
S-VHS socket Yes Scart socket 2
Left Right speaker socket 2 opt. Center speaker socket Opt.

ELECTRICAL CHARACTERISTICS
Power source : AC 165V-265V -50 Hz.
Power consumption : 160W (max.) : 5W (max.) in stby
Audio outputs : 2x8W at 10% THD



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I2C Bus Chassis Service Manual




2. RECOMMENDATION FOR SERVICE REPAIRS
1- Use only original spare parts. Only use outside the cabinet or with back cover removed
components with the same specifications for involve a shock hazard from the receiver.
replacement. Servicing should not be attempted by anyone
2- Original fuse value only should be used. who is not thoroughly familiar with the precau-
tions necessary when working on high voltage
3- Main leads and connecting leads should be
equipment. Perfectly discharge the high poten-
checked for external damage before
tial of the picture tube before handling the tube.
connection.
The picture tube is highly evacuated and if bro-
Check the insulation. ken.
4- Parts contributing to the safety of the product
Glass fragments will be violently expelled.
must not be damaged or obviously unsuitable.
Always discharge the picture tube anode to the
This is valid especially for insulators and insulating
parts. receiver chassis to keep of the shock hazard
before removing the anode cap.
5- Thermally loaded solder pads are to be sucked
off and re-soldered. 8- Keep wire away from the high voltage or high
6- Ensure that the ventilation slots are not temperature components.
obstructed. 9- When replacing a wattage resistor in circuit
7- Potentials as high as 30 KV are present when this board, keep the resistor 10 mm away from circuit
receiver is operating. Operation of the receiver board.




3. HANDLING OF MOS CHIP COMPONENTS
MOS circuit requires special attention with regard until they are used. Most components must never
to static charges. Static charges may occur with be stored in styropor materials or plastic
any highly insulating plastics and can be magazines.
transferred to persons wearing clothes and shoes 2- Persons have to rid themselves of electrostatic
made of synthetic materials. Protective circuits on charges by touching MOS components.
the inputs and outputs of mos circuits give
3- Hold the component by the body touching the
protection to a limited extend only due to time of
terminals.
reaction.
4- Use only grounded instruments for testing and
Please observe the following instructions to protect
the components against damage from static processing purposes.
charges. 5- Remove or connect MOS ICs when operating
1- Keep mos components in conductive package voltage is disconnected.



4. X-RAY RADIATION PRECAUTION
1- Excessive high voltage can be produce be recorded as a part of the service record. It is
potentially hazardous X-RAY radiation. To avoid important to use an accurate and reliable high
such hazard, the high voltage must not be voltage meter.
above the specified limit. The nominal value of 2- The primary source of X-RAY radiation in this TV
the high voltage of this receiver is 25KV at zero receiver is the picture tube. For continued X-RAY
beam current (minimum brightness) under 220V radiation protection, the replacement tube must
AC power source. The high voltage must not be exactly the same type tube as specified in
under any circumstance, exceed 30KV. It is the part list.
recommended the reading of the high voltage




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I2C Bus Chassis Service Manual




5. I2C BUS CHASSIS ADJUSTMENT PROCEDURE
1-System Voltage (+B) Adjustment (optional)