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SERVICE MANUAL
PT-11 CHASSIS
Modification reserved
PT-11 Chassis Service Manual
CONTENTS
PAGE
Recommendation for service repairs 5
Handling of MOS chip components 5
X-Ray radiat>on percolation 5
PT chassis adjustment procedure 6
Scart pin descriptions 7
Component descriptions 8
Fault tracing diagram-power supply 9
Trouble shooting guide for main PCB 10
PT chassis block diagrams 11
Exploded view 13
Placement of chassis 14
Descriptions of the parts 15
1- Switch mode power supply 15
2- Microcontroller stage 15
3- Analog operation part 15
Video IF amplifier 15
Sound IF circuit 16
Synchronization circuit 16
Color decoding 16
4- Vertical deflection circuit 16
5- Horizontal drive circuit 18
6- Sound output stage 19
7- Teletext stage 19
8- CRT stage 19
The details of the boards 21
Extention Boards 22
Main characteristics 28
Board layouts 29
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PT-11 Chassis Service Manual
Oscilloscope shapes 32
RC hand unit and circuit diagram 33
The descriptions of the integrated circuits 35
- TDA8362 35
- TDA4665 38
- TDA8395 39
- CTV 352S/CTV 322S 40
- TDA 4605 42
- Tuner 44
- TDA7057AQ 45
- TDA7056A 46
- TDA4470-B 47
- TDA3845 49
- TBA 120U 51
- SAA 5254 52
- PCF 84C81 (CTV 974) 54
- STV 5346A 55
- TDA9840 56
- SAA 7283 58
- TDA8425 60
- TDA3653B 61
- TDA6103Q 62
Power MOS and hor. drive transistor specs 63
- 3N90 63
- BUH 515D 66
The part list 69
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PT-11 Chassis Service Manual
RECOMMENDATION FOR SERVICE REPAIRS
1- Use only original spare parts. Only use components with the same specifications for replacement.
2- Original fuse value only should be used.
3- Main leads and connecting leads should be checked for external damage before connection.
Check the insulation.
4- Parts contributing to the safety of the product must not be damaged or obviously unsuitable.
This is valid especially for insulators and insulating parts.
5- Thermally loaded solder pads are to be sucked off and re-soldered.
6- Ensure that the ventilation slots are not obstructed.
7- Potentials as high as 25 KV are present when this receiver is operating. Operation of the receiver
outside the cabinet or with back cover removed involve a shock hazard from the receiver.
Servicing should not be attempted by anyone who is not thoroughly familiar with the precautions
necessary when working on high voltage equipment.
Perfectly discharge the high potential of the picture tube before handling the tube. The picture tube is high-
ly evacuated and if broken.
Glass frogments will be violently expelled.
Always discharge the picture tube anode to the receiver chassis to keep of the shock hazard before remo-
ving the anode cap.
8- Keep wire away from the high voltage or high temperature components.
9- When replacing a wattage resistor in circuit board, keep the resistor 10 mm away from circuit board.
HANDLING OF MOS CHIP COMPONENTS
MOS circuit requires special attention with regard to static charges. Static charges may occur with any high-
ly insulating plastics and can be transferred to persons wearing clothes and shoes made of synthetic materi-
als. Protective circuits on the inputs and outputs of mos circuits give protection to a limited extend only due to
time of reaction.
Please observe the following instructions to protect the components against damage from static charges.
1- Keep mos components in conductive package until they are used. Most components must never be sto-
red in styropor materials or plastic magazines.
2- Persons have to rid themselves of electrostatic charges by touching MOS components.
3- Hold the component by the body touching the terminals.
4- Use only grounded instruments for testing and processing purposes.
5- Remove or connect MOS ICs when operating voltage is disconnected.
X-RAY RADIATION PRECAUTION
1- Excessive high voltage can be produce potentially hazardous X-RAY radiation. To avoid such hazard, the
high voltage must not be above the specified limit. The nominal value of the high voltage of this receiver
is 25KV at zero beam current (minimum brightness) under 220V AC power source. The high voltage must
not under any circumstance, exceed 30KV. 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.
2- The primary source of X-RAY radiation in this TV receiver is the picture tube. For continued X-RAY radi-
ation protection, the replacement tube must be exactly the same type tube as specified in the part list.
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PT-11 Chassis Service Manual
PT CHASSIS ADJUSTMENT PROCEDURE
1- System Voltage (+B) Adjustment :
- Before switching on TV, all potentiometers should be adjusted at medium level. Then TV is switched on;
- Adjust all of the analog parameters to minimum with RC
- Adjust P1 trimpot until find +115 V on the cathode of D2 diode
2- AFT Adjustment:
- Place a balloon coil (300 Ohm dc resistance ) parallel to L104
- Apply 80 dB uV 38.9 MHz (39.5 MHz for I ) signal via balloon coil
- Connect a voltmeter to aft pin (pin 9) of IC301
- Adjust T101 coil until the voltage of this pin being 2.5 V dc
3- Adjustment of G2:
- Apply Philips Test pattern
- Adjust all of the analog parameters to minimum with RC
- Adjust G2 trimpot until seeing two bars on gray scale
4- Horizontal and Vertical Adjustment:
- Apply Philips Test pattern signal
- Center the picture horizontally while picture shifting to right and left with P101,
- Make vertical amplitude adjustment with P602 until seeing top and lower lines of picture will be seen
- Center the picture with P601
5- AGC Adjustment:
- Apply Philips Test Pattern whose amplitude is 60 dB uV to the rf input
- Adjust P102 until find a picture without snowy
6- Focus Adjustment:
- Apply Cross-Hatch Pattern signal
- Find the optimum concentration point between H and V intersection in the middle of screen.
7- White Balance Adjustment :
- Apply Philips Test Pattern signal
- Adjust all of the trimpots on CRT board to medium level
- Adjust color, contrast, brightness to minimum by RC
- Adjust G2
- Apply white pattern, settle in the probe of color analyzer to screen
- Increase brightness until geting Y=10 nits
- Adjust x=270 - 276 nits y=270 - 276 nits via "VR201, VR203, VR205"
- Increase brightness and contrast until Y=90 - 100 nits
- Adjust x, y to same values via "VR202 and VR204"
- Check white balance at high and low contrast level. Again make adjustment if it's necessary.
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PT-11 Chassis Service Manual
SPECIFICATIONS OF THE CONNECTOR (EURO SCART)
I- Audio output 1. right channel 0.5 VRMS/ 2- Audio input 1. right channel 0.5 VRMS (connected to No.6)
3- Audio output 2. left channel 0.5 VRMS (connected toNo.1)
4- GND (audio)
5- GND
6- Audio input 2. left channel 0.5 VRMS/>10k 0
7- RGB input, blue (B)
8- Switch signal video (status)
9- GND
10- Reserved for clock signals (not connected)
11- RGB input, green (G)
12- Reserved for remote control (not connected)
13- GND
14- GND switch signal RGB
15- RGB input, red (R)
16- Switch signal RGB
17- GND (video)
18- GND19- Video output 1 Vpp/75 ohm
20- Video input 1 Vpp/75 ohm
21- Shield
1 3 5 7 9 11 13 15 17 19 21
2 4 6 8 10 12 14 16 18 20
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PT-11 Chassis Service Manual
COMPONENT DESCRIPTIONS
POWER CORD
SAW FILTER
IR SENSOR
VOLTAGE REGULATOR
ON/OFF SWITCH
LINE FILTER
PTC
NPN TRANSISTOR
PNP TRANSISTOR
CERAMIC FILTER
COIL
LINEARITY COIL
FUSIBLE RESISTOR
IW METAL OXIDE RESISTOR
1/2W METAL OXIDE RESISTOR
1/4 OR 1/6W CARBON FILM RESISTOR
CERAMIC CAPACITOR /POLYESTER CAPACITOR
ELECTROLITIC CAPACITOR
DIODE
ZENER DIODE
SWITCH JUMPER
NET (INPUT)
NET (OUTPUT)
TACT SWITCH
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FAULT TRACING DIAGRAM-POWER SUPPLY
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TROUBLESHOOTING GUIDE FOR MAIN PCB
TROUBLE CHECK POINTS
No color I101, T102, C127, I102, check pin 38-SSC
No vertical deflection Check +K, I601, pin 42 I401, pin 43 I401
Vertical linearity C 625, R 623
Vertical size C 625, R 624
Vertical shift R 626, P 601
Horizontal linearity L 601, C 608
Horizontal size +B, C 607, L 602
Flue picture I101 pin 25, ABL, FOCUS, HEATER, EHT
Dark picture I101 pin 17, SCREEN, EHT, +M
Noise picture TU01, AGC, IF, FI101
Vert./horizontal synchrony I401
Interference TU01, IF, FI101
No sound Check I101 pin 5 and pin 50, I401 pin 3, pin 5, +G
Low sound I101 pin 5, pin 50, I401 pin 5, +G, R 403
Sound distortion I401, +G, R 403
Contrast I301 pin 5, I101 pin 25, ABL
Brightness I301 pin 3, I101 pin 17
Color saturation I301 pin 4, I101 pin 26
Tuning I301 pin 1, Q 301, +D, TU01
Memory I 302, I 301, SDA, SCL
Band select I 301 pin 7/8, I 303, +K, TU01
No video-out on the SCART Check TV-VID signals, Q 651
No video-in on the SCART Check I301 pin 12, I101 pin 16 on AV mode, check the
video signals on AV mode SCART pin 20 and I101 pin 15
No sound out on the SCART I101 pin 1, Q 653 , Q654
No sound in on the SCART Check the audio signals on SCART pin 2/6 and I101 pin 6
No remote control reception Check signals on pin 3 IR01and I301 pin 35
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THE PLACEMENT OF
CHASSIS
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DESCRIPTONS OF THE PARTS
1- SWITCH MODE POWER SUPPLY STAGE
In order to supply the DC voltage required at various parts of the chassis, a SMPS transformer controlled by
the IC TDA 4605 and switching transistor 3N90 is used. Cl, EM1, C2 filter circuit prevents the network noises
and the effects of high frequency which produced in TV set. After rectifying DC voltage is filtered by using C5.
The stat up voltage of TDA4605 is obtained from R2 at the same time a square wave ii produced from pin 5
of IC TDA4605. This square wave reaches Ql passing through R8. After that Q1 form and induction on TR1,
which produces a voltage on pin 6. This voltage rectified by D6 is used as a supply voltage of IC 1. IC 1 do-
es not operates SMPS by stopping pulses at pin 5, when the network is higher or lower than fixed limits. Pin
2 is control pin of overload. This stage produces 115V for FBT, 12V for audio part, 33 V for tuning circuit 5V,
12V (tuner and some ICs) and 8V (for TDA8362) are produce by the means of the regulators LM7805, LM317
and LM7808. This circuit operates between 165 VAC and 250VAC (5OHz).
2- MICROCONTROLLER STAGE
Below items are controlled or generated by means of these controllers.
l CTV 322S V2.0 (for mono models) and CTV 352S V1.4 (for stereo models) are used as controller on PT
chassis.
l Voltage synthesis tuning
l On screen display
l Control of two transmission standard
l Controls of the simple text or fastext decoder
l Full peri-TV (scart) switching and double scart switching on stereo models,
l Controls of stereo decoder TDA 9840 as German Stereo Decoder
l SAA 7283 as Nicam decoder
l Sound processing (Bass, treble, balance)
l Controls of the analog values of the picture (Brightness, Color, Contrast)
3- ANALOG OPERATION PART WITH TDA 8362
TDA8362 is a single-chip TV processor which contains nearly all small signal functions that are required for
color television receiver. Fora complete receiver the following circuits need to be added a base-band delay li-
ne (TDA4665) a tuner and output stages for audio, video and horizontal and vertical deflection. TDA8362 can
handle signals with positive modulation and it supplies the signals which are required for secam decoder
TDA8395.
VIDEO IF AMPLIFIER
The IF amplifier contains 3 AC-coupled control stages with a total gain control range of greater than 60 dB.The
reference carrier for the video demodulator is obtained by means of passive regeneration of the picture
carrier. The external reference tuned circuit is the only remaining adjustment of the IC.
In the TDA8362 the polarity of the demodulator can be switched so that the circuit is suitable for both positi-
ve and negative modulated signals. The AFC circuit is driven with the same reference signal as the video de-
modulator. To ensure that the video content does not disturb the AFC operation a sample and hold circuit in-
corporated; the capacitor for this function is internal. the AFC output voltages 6V. The AGC detector operates
on levels, top sync for negative modulated and top white for positive modulated signals . The AGC detector
time constant capacitor is connected externally.
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PT-11 Chassis Service Manual
SOUND IF CIRCUIT
On mono models;
The sound bandpass and trap filters have to be connected externally. The filtered intercarrier signal is fed to
a limiter circuit and is demodulated by means of PLL demodulator. The PLL circuit tunes itself automatically
to the incoming signal, consequently, no adjustment is required.
The volume is DC controlled. The composite audio output signal has an amplitude of 700 mV RMS at a volu-
me control setting of -6 dB. The de-emphasis capacitor has to be connected externally. The non-controlled
audio signal can be obtained from pin 1 via a buffer stage. The amplitude of this signal is 350 mV RMS.
The TDA8362 external audio input signal must have an amplitude of 350 mV RMS. The audio/video switch
is controlled via the chrominance input pin.
On stereo models;
On stereo models, the adjustable sound output pin (pin50) is used for mono sound. An external sound IF cir-
cuit TDA3845 is used for NICAM B/G, I stereo systems. For NICAM L stereo system, TDA4470B Sound IF IC
is used so that obtain AM sound and NICAM l sound carrier. On German Stereo system, TBA120U is used
as FM demodulator for second sound carrier.
SYNCHRONIZATION CIRCUIT
The sync separator is preceded by a voltage controlled amplifier which adjusts the sync pulse amplitude to a
fix level. The sync pulses are then fed to the slicing stage (separator) which operates at 50 % of the amplitu-
de.
The separated sync pulses are fed to the first phase detector and to the coincidence detector. The coinciden-
ce detector is used for transmitter identification and to detect whether the line oscillator is synchronized. When
the circuit is not synchronized, the voltage on the peaking control pin (pin 14) is LOW so that this condition
can be detected externally
The IC TDA8362 contains a start up circuit for the horizontal oscillator. When this feature is required a current
of 6.5 mA has to be supplied to pin 36.
COLOR DECODING
TDA8362 contains PAL and NTSC decoder (TDA8361 contains only PAL decoder) but it can cooperate with
the secam add-on secam decoder TDA8395. The communication between two IC's is achieved via pin 32.
The TDA8362 supplies the reference signal (4.43 MHz) for the calibration system of the TDA8395, identifica-
tion of the color standard is via the same connection. When a SECAM signal is detected by the TDA8395 the
IC will draw a current of 150 uA. When TDA8362 has not identified a color signal in this condition it will go in-
to the SECAM mode, that means it will switch of the
R-Y and B-Y outputs and increase voltage level on pin 32.
4- VERTICAL DEFLECTION CIRCUIT WITH TDA3653B
The TDA3653B is vertical deflection circuit for drive of various deflection systems with currents up to 1.5 A pe-
ak to peak. Pin 5 is the output pin. the supply for the output stage is fed to pin 6 and the output stage ground
is connected to pin 4. Pin 1 is the input for the driver of the output stage . The signal at pin 1 is also applied
via external resistors to pin 3 which is the input of the switching circuit. When the flyback starts, this switching
circuit rapidly turns off the lower output stage and so limits the turn-off dissipation. It should be noted that the
lowest voltage at pin 8 is > 2.5 V, during normal operation.
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5- HORIZONTAL DRIVE CIRCUIT
The horizontal drive pulses obtained from pin 37 of the TDA8362 are connected to base of Q601(2SC1573)
via R602 . Q601 drives Q602 (BUH515D) via the drive transformer TR602. TR601 is the EHT transformer. +
B ( 115 V ) is switched by Q602 and TR601 generates both "EHT, FOCUS, G2 voltages required for CPT"
and "170 V, Heater voltage and 26 V vertical supply voltage". The anode beam current information from pin
7 of TR601 is used for reducing contrast at too high beam currents, in order to stabilize the voltages derived
from power supply.
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PT-11 Chassis Service Manual
6- SOUND OUTPUT STAGE
On mono models, TDA7056A is used as sound output amplifier with DC volume control. Pin 50 of the
TDA8362 is AC coupled to the input pin 3 of the TDA7056A via a RC filter. It is supplied by + 12V coming
from a separate winding in the SMPS transformer.
On stereo models, TDA7057AQ is used as sound amplifier. The sound level is controlled by sound proces-
sor TDA8425 via I2C bus on stereo boards. The outputs of TDA8425 ( pin 9 and pin 13 ) is connected to
TDA7057AQ via a divider circuit and two capacitors.
7- TELETEXT STAGE
The teletext stage consists of I SAA5254. On this stage, it should be paid attention that there is video signal
on pin 8 of I SAA5254 after a RCL filter, on condition that existence of the other requirements such as +5V,
periferical components.
Basically, fastext stage consists two I's, STV5346 Teletext decoder and CTV 974 fastext controller with I2C
bus interface. For List Mode a 2K EEPROM (PCF8582) can be added.
8- CRT STAGE
The TDA6103Q is used on CRT stage as video output amplifier. The TDA6103Q consists of three monolithic
video output amplifiers. Each 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 certa-
in frequencies.
The device needs only one power supply voltage (+M ). In contrast to previous types of DMOS video ampli-
fiers, the TDA 6103Q does not need a second supply voltage (12V.), so it saves one wire from motherboard
to CRT stage.
As the TDA 8362 has no white point adjustment and no black current set-up, two adjustments are required
for gain and three adjustments for black setting.
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PT-11 Chassis Service Manual
VID,TXT
I451
SIMPLE TEXT
S451
SIMPLE TEXT PART CIRCUIT DIAGRAM
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PT-11 Chassis Service Manual
THE DETAILS OF THE BOARDS
Mother Board Contains
TDA 8362 multistandard TV processor
CTV 322 / CTV 352 S micro controller with OSD
TDA 4605 Switch Mode Power Supply Controller
TDA 4665 Baseband Delay Line
TDA 8395 Secam Decoder
TDA 7056A Audio Output Amplifier (for mono)
TDA 7057AQ Audio Output Amplifier (for stereo)
PCF 8582 2K EEPROM
TDA 3653B Vertical Driver
SAA 5254 Simple Text Processor
TDA 9830 AM Demodulator
LM 317 Voltage Regulator
LM 7805 Voltage Regulator
LM 7808 Voltage Regulator
Tuner
Infrared Receiver
Horizontal Deflection Part
Degaussing Circuit
4 push buttons ( p+, p-, v+, v-)
Stand By Led
Main Switch
Scart Jack
Extension Connectors
CRT Board
TDA 6103Q Video Output Amplifier
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PT-11 Chassis Service Manual
Extension Boards
Nicam L Board
SAA 7283 QPSK Demodulator, Nicam Decoder
TDA 4470 B SIF and AM Demodulator
TDA 8425 Sound Processor
Nicam BG, I Board
SAA 7283 QPSK Demodulator , Nicam Decoder
TDA 3845 SIF
TDA 8425 Sound Processor
German Stereo Board
TDA 9840 Stereo Processor
TBA 120U SIF
TDA 8425 Sound Processor
Fastext Board
STV5346 Teletext Processor
CTV972 Fastext Processor
PCF8582 2K EEPROM
Double Scart Board
74HC4053 DEMUX
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DOUBLE SCART BOARD CIRCUIT DIAGRAM
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PT-11 Chassis Service Manual
MAIN CHARACTERISTICS
Tube : 90O narrov neckCPT
Chassis : Push through chassis for keyboard
Color And Sound System : European Standards B, G, I, L, L' and
DK with automatic PAL,
SECAM Decoding
Power Source : AC 175V - 250V
Power Consumption : 70W (stereo), 60W (mono)
Stand-By Power Consumption : 12 W
Channel Coverage : VHF ( 2-4, 5-12)
UHF (21-69)
CATV (S1-S41)
Number of Programs : 70 (stereo), 90 (mono)
Audio Outputs : 2*4 Watts (stereo), 4 Watts (mono) at 10% THD
Speakers : 2*8 Ohm (stereo), 8 Ohm (mono)
Antenna Input : 75 Ohm IEC
Standard Features
Auto search
Personal Preference
Auto Shut-off
Scart with RGB
Swap function
Store function on RC
On - Screen Display
Fine tunning
Prog