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Akai 29CT24FS, Руководство по обслуживанию

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SERVICE MANUAL 

2.  AUDIO POWER AMPLIFIER TDA8944J 

2 X 7 W STEREO BRIDGE TIED LOAD (BTL) AUDIO AMPLIFIER 

 

1) General description 

The TDA8944J is a dual-channel audio power amplifier with an output power of 
2 

× 

7 W at an 8 

Ω 

load and a 12 V supply. The circuit contains two Bridge Tied Load 

(BTL) amplifiers with an all-NPN output stage and standby/mute logic. The TDA8944J 
comes in a 17-pin DIL-bent-SIL (DBS) power package. The TDA8944J 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 

❷ 

Few external components 

❷ 

Fixed gain 

❷ 

Standby and mute mode 

❷ 

No on/off switching plops 

❷ 

Low standby current 

❷ 

High supply voltage ripple rejection 

❷ 

Outputs short-circuit protected to ground, supply and across the load 

❷ 

Thermally protected 

❷ 

Printed-circuit board compatible. 

 

3) Block diagram

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fig 9. Block diagram.

 

 

29

Содержание 29CT24FS

Страница 1: ...SERVICE MANUAL Models 29CT24FS 29CT71FS www akai ru COLOUR TV SET ...

Страница 2: ...4 ADJUSTMENTS 5 SET UP ADJUSTMENTS 5 CIRCUIT ADJUSTMENTS 8 STRUCTURE AND CHASSIS FUNCTION DESCRIPTION 18 STRUCTURE BLOCK DIAGRAM 18 BLOCK DIAGRAM FOR SUPPLY VOLTAGE SYSTEM 19 CHASSIS DESCRIPTION 20 SERVICE DATA 21 TECHNICAL DATA OF KEY ICS 21 SERVICE DATA OF KEY ICS 43 REPLACEMENT OF PARTS 46 APPENDIX 1 CIRCUIT DIAGRAM 2 FINAL ASSEMBLY DIAGRAM 3 FINAL WIRING DIAGRAM 4 PRINTED CIRCUIT BOARD LAYOUTS...

Страница 3: ... NTSC3 58 NTSC4 43 50 60Hz Programs preset 236 0 235 Antenna input 75 unbalanced Picture tube Approx Effective screen dimensions 478 363mm Video Audio inputs Composite 3 component 1 S video 1 Power source 170 260V 50Hz Weight Approx 30kg Rated power consumption 110 W Designs and specifications are subject to change without notice 1 Video Audio outputs Composite 1 ...

Страница 4: ...he 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 on...

Страница 5: ...omponents 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 ca...

Страница 6: ... 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 fr...

Страница 7: ...tiometers 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 around the neck of the CRT until the green zone is located vertically at the center of...

Страница 8: ...d 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 assembly on the picture tube 2 2 6 Detach the temporarily mounted wedge and put it in either upper spac...

Страница 9: ...E MANUAL Center Convergence by Convergence Magnets Incline the Yoke Up or Down Incline the Yoke Right or Left Fig 2 4 pole Magnet Movement 6 pole Magnet Movement Circumference Convergence by DEF Yoke Fig 3 7 ...

Страница 10: ...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 for being burned If the fuse is burned out do not power on the TV again until the cause is found out 2 3 Measure voltages of test points with the digital voltmeter Measure the CRT high voltage with the high voltage testing equipment and heater voltage w...

Страница 11: ...sting After Adjusting Fig 4 5 Safety Inspection 5 1 Inspection for insulation and voltage resistant Perform safety test for all naked metal of the TV Supply high voltage of 3000V AC 50Hz limit current of 10mA between all naked metal and cold ground Test every point for 3 sec and ensure no arcing and sparking 5 2 Requirements for insulation resistance Measure resistance between naked metal of the T...

Страница 12: ...1 Soft on Bit5 Step length setting for lighting up gradually during power on 1 Large step 0 Small step Bit4 Screen saver setting 0 No 1 Yes Bit3 M option 0 No 1 Yes Bit2 D K option 0 No 1 Yes Bit1 I option 0 No 1 Yes MODE1 Bit0 B G option 0 No 1 Yes Bit7 Arabic numeral 0 Yes 1 No Bit6 DVD setting bit for AV board TC90L01 0 No 1 Yes Bit5 Tilt correction setting bit 0 No 1 Yes Bit4 SVM in PICTURE me...

Страница 13: ...PU to enable the options BIT 0 English 0 No 1 Yes LANG OUT Ex factory language options with AUTO key 00 English 01 French 02 German 03 Russian 04 Indonesian 05 Malay 06 Farsi 07 Arabic Bit 7 Interval between relay on and off 0 No 1 Yes Bit 6 VCO adjustments 0 PIF VCO functions PIFVCO 10 during auto search and search 1 PIFVCO 10 during turn on and PIFVCO 00 in Normal mode Bit 5 Audio processing 1 Y...

Страница 14: ...Asymmetry sharpness SHPX Sharpness Max SHPN Sharpness Min TXCX Text RGB in user contrast Max RGCN Text RGB in user contrast Min BIT 5 Y peak limiter 0 Off 1 On BIT 4 OSD ABL 0 Active 1 Inactive BIT 3 2 ABL start point 00 ABL start point 0V 01 0 15V 10 0 30V 11 0 45V ABL BIT 1 0 ABL gain 00 0 2V 01 0 4V 10 0 6V 11 0 8V BIT 7 Blank SW 0 H V blanking on 1 H V blanking off Bit 6 Bit 5 4 OSD level 00 O...

Страница 15: ...litudes in PAL and NTSC VLIN V linearity 0 15 8 0 F 15 VSC V S correction 0 16 8 0 F 16 VLIS Adjusting difference between vertical linear in PAL and NTSC VSS Correction for shift data of 50 Hz 60 Hz DPC EW parabola 00 0Vpp 20 1 4Vpp 3F 2 8Vpp DPCS Shift data of EW parabola HIT69 Vertical amplitude in 16 9 mode PAL DPC69 EW parabola 16 9 in 16 9 mode PAL HIT69S Vertical amplitude in 16 9 mode NTSC ...

Страница 16: ...H 010 2H 011 3H 100 4H 101 5H 110 6H 111 7H RSNS R SENSE 00 x 0 20 x 0 5 3F x 1 0 GSNS G SENSE 00 x 0 20 x 0 5 3F x 1 0 BSNS B SENSE 00 x 0 20 x 0 5 3F x 1 0 Bit 6 5 4 PIF FREQUENCY 001 45 75 MHz 011 38 9 MHz 100 38 0 MHz MOD Bit 1 0 AKB MODE 00 AKB off 01 ACB cutoff align to targets 10 ADB drive align to targets 11 AKB cutoff drive align to targets BIT 3 2 VCD STANDBY 00 Normal 01 Normal 10 Norma...

Страница 17: ...g signal received AFC gain 0x00 NOIS BIT 7 BIT 0 Criterion of signal strength NOIS Weak signal NOIS Strong signal VATT Audio ATT 00 85DB or less 7F 0DB 7 BITS BIT 3 Pedestal clip 0 On 1 Off COM1 TC90A49 BIT 2 1 0 VENH2 1 0 000 0db x1 111 3 52db x1 5 BIT 7 6 5 4 Set vertical enhancer non linear point 0000 4LSB 1111 64LSB BIT 3 Set Y output horizontal peaking gain 0 1 5dB 1 3 0dB BIT2 Set Y output h...

Страница 18: ...3 30 WID 16 UCOM 00 C MT 99 ST4 28 HIT69S 01 VTST 00 C MTB 44 SV4 30 DPC69S 01 PYNX 2E C MB F9 SVD 30 DPCS 03 PYNN 18 C MBB 36 ASSH 07 KEYS 00 PYXS 22 C N 9E SHPX 10 WIDS 02 PYNS 1E C NB 36 SHPN 10 ECCT 08 BASC 40 OSDF 70 TXCX 3F ECCB 08 BASX 70 OSD 30 RGCN 1F VEHT 04 TEEC 40 OPT 00 ABL 21 HEHT 01 BALC 40 RCUT 30 DCBS 16 SBY 08 BAS1 3C GCUT 30 CLTO 3F SRY 08 TRE1 40 BCUT 30 CLTS 30 BRTS 17 WFL1 46...

Страница 19: ...COLS 40 VP50 04 FLG0 06 NOIS 01 DCOL 40 HIT 15 FLG1 18 VATT 5D SCOL 00 HPS 03 REFP 00 SCNT 09 VP60 02 RSNS 00 Notes The data sheet may differ dependent on different models The data sheet may differ dependent on different CRTs for the same model The data marked with can be adjusted 17 ...

Страница 20: ... S AV1 AV2 Power Circuit STR G8 656 N801 Degau Circuit ssing 150 250v AC 50Hz Interferen o ce pro Circuit f 5V 1 9V 1 16VB 16VC 16VH 135V CRT Video Amplifier Q901 906 Vertical Out put LA78041 VM EEPROM AT24C16 N230 2 IN1 IC Small Signal Processor MCU CH08T0605 TMPA8827PSNG N210 HV FV SV FBT T401 Horizon ut tal Outp V405 Li e ne Driv V404 ABL VM Amplifier V202 To VM Coil VM Processing Circuit IF Pr...

Страница 21: ...1 VD875 C882 Regul N871 ator Sound Power Ampl N603 ifier 16VC Sampling Amplifier N802 LED RMT Circuit Sound Power Amplifier N603 EEPROM 2 in 1 N210 9V 1 5V 1 135V FBT T401 27V 12V 9V 2 5V 2 VM Circuit Regulator N402 EHT Protection Horizontal Output V405 33V A101 Tuner Regulator VD101 Video Amplifier 2 in 1 N210 150 250v AC 50Hz Degau sing s Circuit Interference proof Circuit P801 P802 CP801 CP802 ...

Страница 22: ...cal output power amplifying TDA8944J mono for audio power amplifying Thick film IC STR G8656 for power circuit adjustment and control AV control TC90L01N The following features are available in the chassis Color systems PAL SECAM Sound systems D K B G 236 programs preset Multilingual on screen display I2 C bus control NICAM AV stereo Selectable picture sound modes Intelligent lock Message board Te...

Страница 23: ...ight 8 85 g typ 1 Features MCU High speed 8 bit CPU TLCS 870 X series Instruction execution time 0 5 μs at 8 MHz TMPA8827CMNG 32 Kbytes ROM 2 Kbytes RAM TMPA8827CPNG 48 Kbytes ROM 2 Kbytes RAM TMPA8827CSNG 64 Kbytes ROM 2 Kbytes RAM ROM correction 12 I O ports 14 bit PWM output 1 ch for a voltage synthesizer 7 bit PWM output 1 channel 8 bit A D converter 3 ch for a touch key input with key ON wake...

Страница 24: ...emodulator without external Tank coil Video Integrated chroma traps Black stretch Y gamma Chroma Integrated chroma BPFs PAL NTSC SECAM demodulation RGB Base Band Integrated 1 H base band delay line Base band TINT control Internal OSD interface Half tone and transparent for OSD External YCbCr interface for DVD RGB cut off drive controls by bus ABCL ABL and ACL combined Sync Integrated fH 640 VCO DC...

Страница 25: ...SERVICE MANUAL 2 Block Diagram Fig 7 Block diagram 23 ...

Страница 26: ...onverter monitoring RF AGC R Y and B Y Functions of SP from MCU are controllable through the IIC bus of the internal connections 3 2 Power Supply TMPA8827 has some power supply and GND pins Power supplies related MCU must be applied at the first Power supplies for H VCC and TV D VCC are the second with at least 100 ms delay after MCU power ON The other power supplies are the last which are recomme...

Страница 27: ...er analog input Timer counter input External interrupt input 4 uP DVSS Power Supply GND 5 Reset I O Reset signal input or watchdog timer output Address trap reset output 6 7 XOUT XIN Output Input X tal connecting pins 8 TEST Input Test pin for out going test Be tied to low 9 uP DVDD 5 V Power Supply VDD Supply 5 V 10 uP VVSS Power Supply GND for Slicer circuit 54 uP MPAGND Power Suppl GND for Osci...

Страница 28: ...e connected capacitor for HAFC filter This terminal voltage controls H VCO frequency 15 V saw Terminal to be connected capacitor to generate V saw signal V saw amplitude is kept constant by V AGC function 16 V OUT Output terminal for Vertical driving pulse 17 H VCC 9 V VCC terminal for DEF circuit Supply 9 V 18 S Filter Terminal to be connected capacitor for SECAM filter 19 Cb input Input terminal...

Страница 29: ...F VCO frequency 36 IF VCC 5V VCC terminal for IF circuit Supply 5 V 37 S Reg F Terminal to be connected capacitor for stabilizing internal bias 38 Deemph Audio out Terminal to be connected capacitor for SIF Det De Emphasis 39 IF AGC Terminal to be connected with IF AGC filter 40 IF GND GND terminal for IF circuit 41 42 IF IN Input terminals for IF signals Pin 41 and Pin 42 are both input poles of ...

Страница 30: ...0 ROUT Output terminal for R signal 51 GOUT Output terminal for G signal 52 BOUT Output terminal for B signal 53 TV AGND GND terminal for Analog block 5 Microcontrollers Descriptions Fig 8 Functional Diagram 6 Refer to Table 13 about Functions and Data of the IC s Pins 28 ...

Страница 31: ...ogic The TDA8944J comes in a 17 pin DIL bent SIL DBS power package The TDA8944J 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 cir...

Страница 32: ...SERVICE MANUAL 4 Pinning information 4 1 Pinning Fig 10 Pin configuration 30 ...

Страница 33: ...8 Negative input 1 IN2 9 Negative input 2 MODE 10 Mode selection input standby mute operating SVR 11 Half supply voltage decoupling ripple rejection IN2 12 Positive input 2 n c 13 Not connected OUT2 14 Negative loudspeaker terminal 2 GND2 15 Ground channel 2 VCC2 16 Supply voltage channel 2 OUT2 17 Positive loudspeaker terminal 2 ground channel 1 TDA8944J Stereo power amplifier Max output power 2 ...

Страница 34: ...ut current of 1 8AP P while LA78041 has supply voltage of 30V and output current of 2 2AP P LA7840 N301 Vertical Deflection Output Circuit 1 Features Low power dissipation due to built in pump up circuit Vertical output circuit Thermal protection circuit built in Excellent crossover characteristics DC coupling possible Package Type TO 220 7H Fig 11 2 Block Diagram Fig 12 Block diagram 3 Refer to T...

Страница 35: ...d Extended Temperature Devices Available 8 lead PDIP 8 lead JEDEC SOIC 8 lead MAP and 8 lead TSSOP Package 2 wire Serial EEPROM AT24C01A 1K 128 x 8 AT24C02 2K 256 x 8 AT24C04 4K 512 x 8 AT24C08 8K 1024 x 8 AT24C16 6K 2048 x 8 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 5...

Страница 36: ...ain driven and may be wired with any number of other open drain or open collector devices DEVICE PAGE ADDRESSES A2 A1 A0 The A2 A1 and A0 pins are device address inputs that are hard wired for the AT24C01A and the AT24C02 As many as eight 1K 2K devices may be addressed on a single bus system device addressing is discussed in detail under the Device Addressing section The AT24C04 uses the A2 and A1...

Страница 37: ...nally organized with 16 pages of 8 bytes each the 1K requires a 7 bit data word address for random word addressing AT24C02 2K SERIAL EEPROM Internally organized with 32 pages of 8 bytes each the 2K requires an 8 bit data word address for random word addressing AT24C04 4K SERIAL EEPROM Internally organized with 32 pages of 16 bytes each the 4K requires a 9 bit data word address for random word addr...

Страница 38: ... same operation principle as STR G5600 Pin configuration function and threshold of STR G8600 are compatible with those of STR G5600 2 Block Diagram Fig 16 Block diagram 3 Function of Terminal Table 11 Terminal No Symbols Description Functions 1 D Drain Terminal MOS FET drain 2 S Source Terminal MOS FET source 3 GND Ground Terminal Ground 4 VIN Power supply Terminal Input of power supply for contro...

Страница 39: ...ions through the bus lines by using a microcomputer This IC has the functions of audio mute ALC Auto Level Control audio volume and so on Fig 17 1 Features I2 C bus control Video 3 channel inputs and 1 channel outputs 1 channels conforming to S system Audio 3 channel inputs and 3 channel outputs Monitor Audio out ALC Auto Level Control Audio volume by attenuator circuit Audio mute 2 I O ports 37 ...

Страница 40: ...n V2 L in TV V in V1 R in V2 R in TV R in V CC GND V CC GND V out Y out C out SCL SDA I O 1 I O 2 TV L out Mon L out TV R out Mon R out 12 15 4 8 2 S 14 13 6 5 9 1 ALC 7 11 3 24 17 16 23 22 18 20 24 I 2 L Logic I 2 C BUS I O Mute 10 Volume Volume 19 21 Fig 18 Block diagram 38 ...

Страница 41: ...SERVICE MANUAL 3 Pin Assignment Fig 19 Pin assignment 39 ...

Страница 42: ...ed to TV R out and Mon R out The input dynamic range of this pin is 6 0 Vp p and the input resistance is 120 k 4 V1 V Y in This pin is for input a luminance signal or composite video signal from an external source V1 channel The signal fed into this pin is presented to V out Y out and C out The input dynamic range of this pin is 2 0 Vp p and the input resistance is 30 k 5 V1 L in This pin is for i...

Страница 43: ...his pin is 6 0 Vp p and the input resistance is 120 10 ALC This is an detect output pin of ALC Auto Level Control It controls ALC 11 V2 R in This pin is for input a right audio signal from an external source V2 channel The signal fed into this pin is presented to TV R out and Mon Rout The input dynamic range of this pin is 6 0 Vp p and the input resistance is 120 k 12 VCC This is the power supply ...

Страница 44: ...V in or TV V in is outputted from this pin 21 I O ２ This is an ADC input DAC output pin The ADC is a 2 level detection type 1 bits The threshold level is 3 0 V The DAC 1 bit is an open drain output Make sure that the current flowing into this pin is 2 0 mA or less 22 V out This pin is for output the main channel composite video signal The signal fed into TV V in V1 V in V2 V in or V1 Y in _V1 C in...

Страница 45: ... KΩ 10 26 26 26 26 0 26 26 Pin No 25 26 27 28 29 30 31 32 Voltage V 3 4 1 9 4 85 5 4 8 84 3 1 0 3 8 Resistance KΩ 10 3 26 24 2 22 9 0 39 3 32 3 3 2 9 Pin No 33 34 35 36 37 38 39 40 Voltage V 2 97 2 44 2 49 4 96 2 2 4 39 1 8 0 Resistance KΩ 26 24 8 26 1 6 20 22 8 26 0 Pin No 41 42 43 44 45 46 47 48 Voltage V 1 6 1 6 2 4 4 9 2 5 3 3 2 4 0 Resistance KΩ 26 26 12 9 1 6 3 3 26 26 0 Pin No 49 50 51 52 5...

Страница 46: ... selection input standby mute operating 0 7 8 8 9 11 Half supply voltage decoupling ripple rejection 7 6 12 Positive input 2 7 3 13 Not connected 0 14 Negative loudspeaker terminal 2 7 3 15 Ground channel 2 0 0 0 16 Supply voltage channel 2 14 8 3 5 3 5 17 Positive loudspeaker terminal 2 7 3 Table 15 Functions and Service Data of LA78040 78041 N301 s Pins GDM8145 Multimeter Ground Resistance KΩ Pi...

Страница 47: ...istance 20KΩ 1 Address input 0 0 001 0 00 2 Address input 0 0 001 0 00 3 Address input 0 0 001 0 00 4 Common ground 0 0 001 0 00 5 Clock line 5 7 4 83 6 Data line 4 99 6 9 5 15 7 PW write protect 4 99 9 5 5 31 8 Supply voltage 5 3 5 3 25 Table 17 Functions and Service Data of STR G8656 N801 s Pins Digital Multimeter Pin No Functions Description Reference Voltage V Positive Resistance 20KΩ Negative...

Страница 48: ...he one which has the same safety characteristics as specified in the 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 ...

Страница 49: ...APPENDIX CIRCUIT DIAGRAM 1 JUC7 820 1117 ...

Страница 50: ...CIRCUIT DIAGRAM 2 JUC7 820 1014 8 5 JUC7 820 1151 CRT RGB SIDE AV BOARD ...

Страница 51: ...ing coil with the wire clip XJ 100 9 to make the wire far 5 Tie the degaussing coil with the wire clip XJ 100 9 to make the wire far 4 Insert the wire clip B 16 into the slot on the rear terminal board 4 Insert the wire clip B 16 into the slot on the rear terminal board After inspection and ensuring O K Reinstall the back cover After inspection and ensuring O K Reinstall the back cover 3 Connect w...

Страница 52: ...Yoke To Deflection Yoke W r i ed Connector XS800 W r i ed Connector XS800 Screen Wire Grey Screen Wire Grey Focus Wire Red Focus Wire Red CRT s Ground Wire CRT s Ground Wire Soldered Soldered First soldered the focus wire First soldered the focus wire then close the cover then close the cover 2 0 B B 0 6 1 2 0 B B 0 6 1 Input Input Wired Connector XPL01 Wired Connector XPL01 Input Input W r i ed C...

Страница 53: ...PRINTED CIRCUIT BOARD DIAGRAMS MAIN ...

Страница 54: ...CRT RGB PRINTED CIRCUIT BOARD AV PRINTED CIRCUIT BOARD ...

Страница 55: ...POWER PRINTED CIRCUIT BOARD ...

Страница 56: ...PARTS ON SOFT SWITCH PRINTED CIRCUIT BOARD SIDE AV PRINTED CIRCUIT BOARD REMOTE SENSOR AND INDICATOR PRINTED CIRCUIT BOARD ...

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