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Changhong Electric 34T18 Service Manual Download Page 47

SERVICE MANUAL 

 

45

Waveform during V404’s Base 
T=64us

 

Summary of Contents for 34T18

Page 1: ...FILE NO SM CTV O 123 COLOR TELEVISION MODEL NO PF29T18 34T18 CPF29T99 CHASSIS NO CH 20 Please read this manual carefully before service SERVICE MANUAL ...

Page 2: ... INSTRUCTIONS 1 ADJUSTMENTS 4 STRUCTURE AND CHASSIS FUNCTION DESCRIPTION 17 SERVICE DATA 17 REPLACEMENT OF PARTS 55 APPENDIX 1 CIRCUIT DIAGRAMS 2 PRINTED CIRCUIT BOARD LAYOUTS 3 FINAL ASSEMBLY DIAGRAMS 4 FINAL WIRING DIAGRAMS ...

Page 3: ... the maximum EHT voltage does not exceed the rated value after service and adjustment SAFETY PRECAUTION WARNING REFER SERVICING TO QUALIFIED SERVICE PERSONNEL ONLY 1 The TV has a nominal working EHT voltage Extreme caution should be exercised when working on the TV with the back removed 1 1 Do not attempt to service this TV if you are not conversant with the precautions and procedures for working ...

Page 4: ... components read the parts list in this manual carefully Substitute replacement components which do not have the same safety characteristics as specified in the parts list may create X ray radiation 2 Do not slap or beat the cabinet or CRT since this may result in fire or explosion 3 Never allow the TV sharing a plug or socket with other large power equipment Doing so may result in too large load ...

Page 5: ...or heat register or where it is exposed to direct sunlight 2 Do not install the TV set in a place exposed to rain water excessive dust mechanical vibrations or impacts 3 Allow enough space at least 10cm between the TV and wall or enclosures for proper ventilation 4 Slots and openings in the cabinet should never be blocked by clothes or other objects 5 Please power off the TV set and disconnect it ...

Page 6: ...ss and contrast to maximum 1 6 Counter clockwise rotate the R B low brightness potentiometers to the end and rotate the green low brightness potentiometer to center 1 7 Receive green raster pattern signals 1 8 Loosen the clamp screw holding the deflection yoke assembly and slide it forward or backward to display a vertical green zone on the screen Rotate and spread the tabs of the purity magnet ar...

Page 7: ... front of the deflection yoke up or down to obtain better convergence in circumference Push the mounted wedge in to fix the yoke temporarily 2 2 3 Put the second wedge into bottom 2 2 4 Move front of the deflection yoke to the left or right to obtain better convergence in circumference 2 2 5 Fix the deflection yoke position and put the third wedge in either upper space Fasten the deflection yoke a...

Page 8: ... data to adjust white balance Fig 2 4 pole Magnet Movement 6 pole Magnet Movement Center Convergence by Convergence Magnets Incline the Yoke Up or Down Incline the Yoke Right or Left Circumference Convergence by DEF Yoke Fig 3 ...

Page 9: ... Turn on the degausser Slowly move it around the screen and slowly take it away from the TV 1 5 Repeat the above steps until the TV is degaussed completely 2 Confirmation and Adjustment for Voltage Caution B voltage has close relation to high voltage To prevent X ray radiation set B voltage to the rated value 2 1 Power on the TV and receive Philips test pattern 2 2 Check the resistors and coils fo...

Page 10: ... high voltage reading should be less than the limited EHT voltage 3 4 Change the brightness from minimum to maximum and ensure high voltage not beyond the limitation in any case Nominal EHT voltage Limited EHT voltage Remarks 29KV 1 5KV 33KV for 29 CRT 31 0KV 1 5KV 35KV for 34 CRT Note The data sheet may differ dependent on different CRTs 4 Focus Adjustment Caution Dangerously high voltages are pr...

Page 11: ...z 5VOF 6VOF Set to the optimal mode Character position for 50 60Hz 5HP 6HP Set to the optimal mode Parallelogram correction for 50 60Hz 5HB 6HB Set to the optimal mode Curve correction for 50 60Hz 5HSH 6HSH Set to the optimal mode Horizontal center for 50 60Hz 5HA 6HA Set to the optimal mode Horizontal amplitude for 50 60Hz 5EW 6EW Set to the optimal mode Pincushion and barrel correction for 50 60...

Page 12: ...litude COR 3 WS 0 White stretch setting HDOL 0B Cathode drive level AGCS 1 AGC speed VG2B 24 Brightness setting when adjusting G2 VENH 03 Vertical enhance CBNR 03 Comb noise reduce TRE1 64 TRE2 32 Treble linearity BAS1 64 BAS2 32 Bass linearity VOLA 40 53 MSP3410G TDA7442 VOLB 46 58 MSP3410G TDA7442 VOLC 4B 60 MSP3410G TDA7442 VOLD 51 63 MSP3410G TDA7442 LOUD 20 Loudness not for TDA7442 SC1 74 SCA...

Page 13: ...odels The data sheet may differ dependent on different CRTs for the same model Designs and specifications are subject to change without notice Table 3 Option bit setting Bit Item Description 0 OP_NICAM 1 MSP3410 0 TDA7442 1 OP_COMB 1 Yes 0 No 2 OP_SVM 1 Yes 0 No 3 OP_AV2 1 Yes 0 No 4 OP_FAV 1 Yes 0 No 5 OP_FAVS 1 Yes 0 No 6 OP_STORE 0 West Europe 1 East Europe OP1 7 OP_OSO 1 0 OP_AVC 1 MSP3410 0 T...

Page 14: ...FMWS 1 1 OP_POWER 1 Memory on 0 Soft on 2 OP_COUNTRY 1 COUNTRY display option 3 OP_LOGO 0 LOGO display not available 4 OP_DFL 1 5 OP_BLUE_BACK 0 Blue back not available under no signal condition 1 Blue back available under no signal condition 6 OP_ACI 1 Yes 0 No OP4 7 OP_ATS 1 Yes 0 No 0 OP_LANG0 0 1 OP_LANG1 0 2 OP_LANG2 0 3 OP_LANG3 0 4 OP_SOUND0 0 5 OP_SOUND1 0 6 OP_SOUND2 1 OP5 7 OP_STRIKE 1 0...

Page 15: ...5 Bit4 in OP5 are outgoing audio option settings as follows 000 East Europe D K 001 West Europe B G 010 UK I 110 France L 100 Europe Auto Bit3 Bit2 Bit1 and Bit0 in OP5 are outgoing language option settings as follows English French German Spanish Danish Dutch Finnish Greek Italian Norwegian Portuguese Swedish and Turkish successively begun with ...

Page 16: ... N603 Speakers Audio Processor TDA7442 N602 5V Filament Vertical Output TDA8359 N401 Horizontal Output V404 FBT T402 ABL Circuit HV FV SV 200V 14V Voltage E W V out H out IIC Power Circuit STR W6856 N801 15V 1 12V 145V 3 3V 3 9V 220 240V AC 50 60Hz 15V 2 38 48 42 R G B Input IFO TV CVBS CVBS 2 AV CVBS CVBS 1 In Y C AV CVBS Y C R L1 In R L3 In R L2 In R L2 Out Main R L 47 40 Audio Out V out EHT Cir...

Page 17: ... Amplifier TDA8944J N603 VD414 VD411 VD412 Video Amplifier TDA6108JF 8V 5V Regulator V405 UOC TDA9594 N101 VD819 VD815 Audio Processor TDA7442 N602 Audio Out Amplifier V303 V304 V310 V311 Video Out Amp lifier V301 V302 Y C Amplifier V505 V510 ABL EHT Circuit CRT RGB Board Tuner A001 Comb Filter TC90A49 Video Switch HEF4052 Control Signal Driver Circuit Including KAV etc VD816 15V 1 Line Drive Circ...

Page 18: ... channel 7W 7W distortionless THD 7 Selectable sound modes Music Theatre Speech Personal Selectable picture modes Personal Rich Natural Soft AV stereo audio processing MSP34XX or TDA7442 PAL NTSC 3 line comb filter Earphone output Selectable aspect ratio 4 3 16 9 Zoom Auto identification and changeover of vertical frequency 50 60Hz Auto identification of SCART picture input format 4 3 16 9 Auto id...

Page 19: ...luminance delay line with adjustable delay time Picture improvement features with peaking with switchable centre frequency depeaking variable positive negative overshoot ratio and video dependent coring dynamic skin tone control and blue and black stretching Scan Velocity Modulation output Integrated chroma band pass filter with switchable centre frequency Only one reference 12 MHz crystal require...

Page 20: ...sion IF and mono intercarrier sound circuit can be used for the demodulation of FM radio signals The QSS and mono FM functionality are both available so that an FM AM TV receiver can be built without the use of additional ICs Video switch with 2 external CVBS inputs and a CVBS output One of the CVBS inputs can be used as Y C input 2 external audio inputs The selection of the various inputs is coup...

Page 21: ...anking Interval VBI data capture of WST data Display Teletext and Enhanced OSD modes Features of level 1 5 WST and US Close Caption 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 40...

Page 22: ...for comb filter applications QSS sound IF amplifier with separate input and AGC circuit AM sound demodulator without extra reference circuit Generation of a Mixed down I signal for the demodulation of DVB signals FM radio option via QSS amplifier FM radio option with FM tuner PAL decoder SECAM decoder NTSC decoder Horizontal geometry E W Horizontal and vertical zoom ROM size 64 k 64 28k 64 k 32 64...

Page 23: ... IREF 20 25 reference current input VSC 21 26 vertical sawtooth capacitor AGCOUT 22 27 tuner AGC output SIFIN1 DVBIN1 1 23 28 SIF input 1 DVB input 1 SIFIN2 DVBIN2 1 24 29 SIF input 2 DVB input 2 GND2 25 30 ground 2 for TV processor SNDPLL AVL REF0 SNDIF REFIN 1 26 27 32 narrow band PLL filter Automatic Volume Levelling subcarrier reference output sound IF input external reference signal input for...

Page 24: ...C 61 56 digital supply to core 3 3 V OSCGND 62 57 oscillator ground supply XTALIN 63 58 crystal oscillator input XTALOUT 64 59 crystal oscillator output RESET 65 60 reset VDDP 66 61 digital supply to periphery 3 3 V P1 0 INT1 67 62 port 1 0 or external interrupt 1 input P1 1 T0 68 63 port 1 1 or Counter Timer 0 input P1 2 INT0 69 64 port 1 2 or external interrupt 0 input P1 3 T1 70 1 port 1 3 or C...

Page 25: ...N OSD TEXT INSERT CCC WHITE P ADJ 80C51 CPU I 2 C BUS TRANSCEIVER ROM RAM TELETEXT ACQUISITION 1 10 PAGE MEMORY TELETEXT OSD DISPLAY R G B BL Y U V H V REF ENHANCED VST PWM DAC VST OUT I O PORTS I O PORTS 4x 3 3 V RESET LED OUT 2x ADC IN 4x VPE EW GEOMETRY GEOMETRY EHTO EWD R V G Y B U BL RGB YUV INSERT R G B REF CVBS SYNC H V COR SATURATION LUMA DELAY PEAKING BLACK STRETCH QSS SOUND IF AGC QSS MI...

Page 26: ...1 O INT1 RESET P2 2 PWM1 P2 1 PWM0 P2 0 PMW P1 7 SDA P1 3 T1 P1 1 T0 VDDP P2 4 PWM3 P2 5 PWM4 SYNC_FILTER CVBS3 Y C WHSTR CVBSO AUDOUT AMOUT INSSW2 R2 VIN VPE VDDA BO GO RO BLKIN BCLIN B2 UIN G2 YIN XTALOUT XTALIN OSCGND VDDC GND CVBS2 GND SVM FBISO HOUT GND2 AMOUT QSSO AUDEEM SNDPLL DVBO SVO IFOUT DVBO PLLIF VP1 CVBS1 EHTO AVL REFOUTSNDIF REFIN DECSDEM AUDIO2 AUDIO3 SIFAGC DVBAGC VDRA IFIN1 IFIN2...

Page 27: ...7 36 35 34 33 T D A 9 59X s eries S D IP 64 P1 3 T1 P1 6 SCL P1 7 SDA P2 0 TPMW P3 0 ADC0 P3 1 ADC1 P3 2 ADC2 P3 3 ADC3 VSSC P P0 5 P0 6 VSSA SECPLL VP2 DECDIG HOUT FBISO PH2LF PH1LF GND3 EWD VDRB VDRA IFIN1 IFIN2 EHTO IREF VSC AGCOUT SIFIN1 DVBIN1 SIFIN2 DVBIN2 PLLIF IFVO SVO DVBO DECBG CVBS1 VP1 C CVBS Y GND SVM REFO AMOUT BLKIN BO GO RO BCLIN R2 VIN B2 UIN G2 YIN INSSW2 VDDA VPE VDDC OSCGND XTA...

Page 28: ...es Data Retention 100 Years Automotive Grade and Extended Temperature Devices Available Fig 10 8 Pin and 14 Pin JEDEC SOIC and 8 Pin PDIP Packages 2 Description The AT24C01A 02 04 08 16 provides 1024 2048 4096 8192 16384 bits of serial electrically erasable and programmable read only memory EEPROM organized as 128 256 512 1024 2048 words of 8 bits each The device is optimized for use in many indus...

Page 29: ...SERVICE MANUAL 27 4 Block Diagram Fig 11 5 Refer to Table 13 about Functions and Data of the IC s Pins ...

Page 30: ...unction All Functions Programmable Via Serial Bus 2 Monitor Output Only For Tda7442 2 Description The TDA7442 42D is volume tone bass and treble balance Left Right processors for quality audio applications in TV and Hi Fi systems It reproduces surround sound by using a programmable phase shifter Control of all the functions is accomplished by serial bus The AC signal setting is obtained by resisto...

Page 31: ...R L R 30K 30K 2 2mF 2 2mF MUXOUT R IN R MUXOUT L IN L L IN1 5 6 7 8 2 1 32 31 4 11 13 18 2 7 28 2 6 22 14 13 29 23 25 24 30 17 16 20 19 3 10 9 L R 0 47mF SUPPLY VS AGND CREF TREBLE BASS BIN L MUTE D98AU947B I2C BUS DECODER LATCHES SPKR ATT TREBLE BASS 5 6nF MUTE SPKR ATT SCL SDA DIG GND ROUT LOUT 22mF R IN4 0 47mF 50K PS1 90Hz 100nF PS1 RPS1 SYMULATED MUSIC MUSIC SYMULATED OFF MIXING AMP LPF 9KHz ...

Page 32: ...A8944J is printed circuit board PCB compatible with all other types in the TDA894x family One PCB footprint accommodates both the mono and the stereo products 2 Features Few external components Fixed gain Standby and mute mode No on off switching plops Low standby current High supply voltage ripple rejection Outputs short circuit protected to ground supply and across the load Thermally protected P...

Page 33: ...r 50 for TDA6107Q Black Current Stabilization BCS circuit Thermal protection 2 General Description The TDA6107Q 6108JF includes three video output amplifiers in one plastic DIL bent SIL 9 pin medium power DBS9MPF package SOT 111 1 using high voltage DMOS technology and is intended to drive the three cathodes of a colour CRT directly To obtain maximum performance the amplifier should be used with b...

Page 34: ...e IC s Pins Symbol Pin Description Vi 1 1 Inverting input 1 Vi 2 2 Inverting input 2 Vi 3 3 Inverting input 3 GND 4 ground fin Iom 5 Black current measurement output VDD 6 Supply voltage Voc 3 7 Cathode output 3 Voc 2 8 Cathode output 2 Voc 1 9 Cathode output 1 Fig 13 Pin Configuration ...

Page 35: ...LL 8 multiplier circuit Internal 8 bit 4 fsc AD converter Internal 8 bit precision 8 fsc DA converter 2 ch Sync tip clamp circuit Internal 4H line memory I2 C bus interface Package DIP 20 pin and SOP 24 pin 5V single power supply 2 Block Diagram 3 Pin Assignment 4 Refer to Table 16 about Functions and Service Data of the IC s Pins Fig 14 Fig 15 Fig 16 ...

Page 36: ...nd A1 With E HIGH all switches are in the high impedance OFF state independent of A0 and A1 VDD and Vss are the supply voltage connections for the digital control inputs A0 A1 and E The VDD to Vss range is 3 to 15 V The analog inputs outputs Y0 to Y3 and Z can swing between VDD as a positive limit and VEE as a negative limit VDD VEE may not exceed 15 V For operation as a digital multiplexer demult...

Page 37: ...awing VDD current out of terminal Z when switch current flows into terminals Y the voltage drop across the bidirectional switch must not exceed 0 4V If the switch current flows into terminal Z no VDD current will flow out of terminals Y in this case is no limit for the voltage drop across the switch but the voltages at Y and Z may not exceed VDD or VEE 4 Refer to Table 17 about Functions and Data ...

Page 38: ... designed in such way that only a few external components are needed to get a correct working application The TDA8359J is functional the same as the TDA8357J vertical deflection output stage The TDA8359J differs in only one aspect from the TDA8357J it is able to deliver a higher output current which is more suitable for large picture tubes A detailed investigation procedure to determine an optimum...

Page 39: ...E MANUAL 37 3 Block Diagram Fig 21 INPUT AND FEED BACK CIRCUIT GUARD CIRCUIT TDA8359J 9 7 M2 M5 M4 M1 M3 D1 D3 D2 4 5 2 1 8 6 3 INA INB GND GUARD V V 0 0 OUTB OUTA FEEDB P FB V V i p p i p p V i bias i bias V ...

Page 40: ... generally called TO220 affording dielectric isolation Guarantees space of 1 8mm between high voltage pin and other pins thus high voltage MOSFET built in allowed Offers low startup current by employing BCD Process Automatic change over of QR and MBS operations With MOSFET turn on at the bottom of VDS STR W 6800 Series ICs offers high efficiency and low noise at the wide areas from the heavy load ...

Page 41: ... Supply voltage 5 OCP BD Over current protection detection Bottom detection 6 FB OLP Feedback Over load protection detection 7 RTFC Time Fix Control regulation 5 Refer to Table 18 about Functions and Data of the IC s Pins Vcc 4 Pin D 1 Pin S GND 3 Pin OCP BD 5 Pin Drive REG DRV REG OCP BIC BD BEC TFC OSC Current Mirror Current Mirror OLP TSD OVP S Q R REG LATCH RTFC 7 Pin FB OLP 6 Pin ...

Page 42: ...SERVICE MANUAL 40 2 WAVEFORMS OF KEY POINTS Waveform during C802 Startup Waveform during B Voltage Startup ...

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Page 47: ...SERVICE MANUAL 45 Waveform during V404 s Base T 64us ...

Page 48: ...SERVICE MANUAL 46 Waveform during V404 s C Electrode ...

Page 49: ...SERVICE MANUAL 47 ...

Page 50: ... ADC2 6 8 3 P3 3 ADC3 1 3 0 196 4 VSSC P 0 0 5 P0 5 10 4 0 6 P0 6 CVBSTD 10 4 0 7 VSSA 0 0 8 SECPLL 5 420 9 VP2 1 1 7 68 10 DECDIG 30 6 11 PH2LF 5 410 12 PH1LF 5 450 13 GND3 0 0 14 DECBG 38 15 EWD 1 760 16 VDRB 3 03 17 VDRA 3 03 18 IFIN1 36 4 1 89 19 IFIN2 36 4 1 9 20 IREF 38 9 21 VSC 5 440 22 AGCOUT 1 7 2 0 23 SIFIN1 DVBIN1 1 36 5 1 89 24 SIFIN2 DVBIN2 1 36 6 1 89 25 GND2 0 0 26 SNDPLL Continued ...

Page 51: ...F 5 440 36 SIFAGC DVBAGC 1 5 000 37 INTCO DVBO 1 38 IFVO SVO DVBO 1 3 660 2 05 39 VP1 1 1 7 6 40 CVBS1 5 230 41 GND 0 0 42 CVBS2 5 380 43 GND 0 0 44 CVBS3 Y 5 340 3 74 45 C 82 3 1 47 46 WHSTR 5 190 47 CVBSO 5 500 48 AUDOUT AMOUT 5 500 49 SVM 5 500 4 5 50 INSSW2 0 075 51 R2 VIN 5 500 2 5 52 G2 YIN 5 500 2 5 53 B2 UIN 5 500 2 5 54 BCLIN 0 069 3 7 55 BLKIN 23 3 2 56 RO 5 8 2 7 Continued ...

Page 52: ...5 64 XTALOUT 5 1 5 65 RESET 0 0 66 VDDP 0 28 3 3 67 P1 0 INT1 10 0 06 68 P1 1 T0 10 0 06 69 P1 2 INT0 12 200 3 3 70 P1 3 T1 0 19 0 7 71 P1 6 SCL 8 7 3 7 72 P1 7 SDA 9 3 8 73 P2 0 TPWM 10 5 0 06 74 P2 1 PWM0 2 5 0 1 75 P2 2 PWM1 3 7 0 06 76 P2 3 PWM2 6 2 0 05 77 P2 4 PWM3 78 P2 5 PWM4 10 6 0 1 79 SYNC_FILTER 3 700 80 P3 0 ADC0 ...

Page 53: ...4 9 3 03 3 02 Table 14 Functions and Service Data of TDA8944J N603 s Pins Digital Multimeter Pin No Functions Description Reference Voltage V Positive Resistance 20KΩ Negative Resistance 20KΩ 1 Negative loudspeaker terminal 1 7 98 2 Ground channel 1 0 0 0 3 Supply voltage channel 1 14 9 5 8 7 7 4 Positive loudspeaker terminal 1 7 3 5 Not connected 0 6 Positive input 1 7 3 7 Not connected 0 8 Negat...

Page 54: ...KΩ 1 G inverting input 3 33 5 32 4 72 2 R inverting input 3 26 5 32 4 72 3 B inverting input 3 28 5 32 4 72 4 Ground 0 00 0 00 0 00 5 Black level current input 6 03 18 65 5 65 6 Supply voltage 199 4 48 7 B output 69 9 5 45 8 R output 69 18 5 45 9 G output 65 9 5 45 Table 16 Functions and Service Data of TC90A49P N501 s Pins Digital Multimeter Pin No Functions Description Reference Voltage V Positi...

Page 55: ...ND digital 0 0 0 8 Internal DRAM power supply 4 98 0 55 0 55 9 I 2 C BUS SDA 4 12 6 39 6 44 10 I 2 C BUS SCL 4 25 6 4 6 45 11 Shipment test mode switch or I 2 C bus setting reset pin 0 0 0 12 Y signal comb function ON OFF switch 0 0 0 13 Clock input pin 2 54 14 Connect the APC filter in the 8 fsc PLL circuit 0 15 PLL power supply 4 98 0 55 0 55 16 ADC DAC and PLL GND analog 0 0 0 17 Outputs chromi...

Page 56: ...Pin No Function Description Reference Voltage V Positive Resistance KΩ Negative Resistance KΩ 1 Signal input 0 12 52 6 46 2 Signal input 0 12 5 6 46 3 Signal input 0 12 52 6 46 4 Signal output 0 12 43 6 25 5 Signal input 0 12 5 6 46 6 Ground 0 0 0 7 Ground 0 0 0 8 Ground 0 0 0 9 Control signal input 4 98 7 8 5 6 10 Control signal input 4 98 7 8 5 6 11 Control signal input 0 0 0 12 Signal input 0 0...

Page 57: ...manual Description of the special markings A The components identified by the A marking have special safety related characteristics AE The components identified by the AE marking are listed by EMC and have special safety related characteristics CB The components identified by the CB marking have been evaluated to the CB standard E The components identified by the E marking are listed by EMC G The ...

Page 58: ...cifications are subject to change without reference 1 Any components identified by have special safety related characteristics Use replacement Which have the same characteristics as original parts 2 Cold ground Hot ground Circuit Diagram 1 APPENDIX ...

Page 59: ...Circuit Diagram 2 ...

Page 60: ...MAIN PCB ...

Page 61: ...CRT RGB PCB ...

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