Akai 25CT23FSR Service Manual
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Akai 25CT23FSR Service Manual

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COLOUR TV SET
Models:
25CT23FSR
29CT23FSR
SERVICE MANUAL
www.akai.ru

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Summary of Contents for Akai 25CT23FSR

  • Page 1 COLOUR TV SET Models: 25CT23FSR 29CT23FSR SERVICE MANUAL www.akai.ru...

  • Page 2: Table Of Contents

    SERVICE MANUAL TABLE OF CONTENTS TABLE OF CONTENTS ....................1 SAFETY INSTRUCTIONS AND MAINTENANCE ......... 2 X-RAY RADIATION PRECAUTION ..................2 SAFETY PRECAUTION ......................2 PRODUCT SAFETY NOTICE ....................3 SAFETY SYMBOL DESCRIPTION ................... 3 MAINTENANCE ..........................4 ADJUSTMENTS ........................5 SET-UP ADJUSTMENTS ......................

  • Page 3: Safety Instructions And Maintenance

    INSTRUCTIONS FOR SERVICE SAFETY AND MAINTENANCE WARNING: BEFORE SERVICING THIS CHASSIS, READ THE X-RAY RADIATION PRECAUTION , SAFETY PRECAUTION AND PRODUCT SAFETY NOTICE INSTRUCTION BELOW. X-RAY RADIATION PRECAUTION 1. The EHT must be checked every time the TV is serviced to ensure that the CRT does not emit X-ray radiation as result of excessive EHT voltage.

  • Page 4: Product Safety Notice

    6. When remounting the TV chassis, ensure that all guard devices, such as nonmetal control buttons, switch, insulating sleeve, shielding cover, isolating resistors and capacitors, are installed on the original place. 7. Replace blown fuses within the TV with the fuse specified in the parts list. 8.

  • Page 5: Maintenance

    have special safety-related characteristics. C UL This symbol tells you that the critical components identified by the C-UL marking have been evaluated to the UL and C-UL standards and have special safety-related characteristics. This symbol tells you that the critical components identified by the VDE marking have special safety-related characteristics.

  • Page 6: Adjustments

    ADJUSTMENTS SET-UP ADJUSTMENTS The following adjustments should be made when a complete realignment is required or a new picture tube is installed. Perform the adjustments in the following order: 1. Color purity 2. Convergence 3. White balance Notes: The purity/convergence magnet assembly and rubber wedges need mechanical positioning.
  • Page 7 Fig. 1 2.1.4 Turn both tabs at the same time keeping the angle constant to superimpose red and blue horizontal on the center of the screen. 2.1.5 Adjust two tabs of the 6-pole magnet to superimpose red/blue line and green line. 2.1.6 Remember red and blue movement.
  • Page 8 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: Circuit Adjustments

    CIRCUIT ADJUSTMENTS Preparation: Circuit adjustments should be made only after completion of set-up adjustments. Circuit adjustments can be performed using the adjustable components inside the TV set. For TVs with I C bus control, first change the bus data. 1. Degaussing A degaussing coil is built inside the TV set.
  • Page 10 3.1 Connect a precise static high voltmeter to the second anode (inside the high voltage cap) of the CRT. 3.2 Plug in the supply socket (150-250V ~, 50Hz) and turn on the TV. Set the brightness and contrast to minimum (0 A). 3.3 The high voltage reading should be less than the limited EHT voltage.
  • Page 11 Use the / buttons on the remote control to highlight an adjustment and the buttons to adjust it. The POS+/-, / / / ,1~6, RECALL, VOL+/-, MUTE and POWER buttons on the remote control function in the S mode, but 100+, 7, 8, 9 and 0 buttons not. 6.2 Bus data Table 3 Bus data...
  • Page 12 East-west pincushion correction (When vertical frequency is Set to the optimum identified to 50Hz, “5EW” is displayed when identified to 60Hz, “6EW” displayed.) Set to the optimum Upper corner correction Set to the optimum Bottom corner correction Set to the optimum Trapezoidal correction RCUT Set to the optimum...
  • Page 13 OP_RGB RGB 1: Yes, 0: No OP_AVL AVL 1: Yes, 0: No OP_AUTO_SOUND Auto sound system test: 1:Yes, 0: No OP_KEY Key: 1: Standard 0: Non-standard OP_OSO Switch off in vertical overscan OP_NOT_3 National option (disabled) OP_USER_LOGO User write-in logo option (prior to Changhong logo) OP_ON_BACK Power-on auto-test background: 1: Blue, 0: Black OP_FSL...
  • Page 14 example: OP_AUTO_LANG2 LANG2 /LANG1/ LANG0 0/0/0”: English, “0/0/1”: Farsi OP_FORF Vertical frequency (OP_FORS/FORF): 00-Auto (60Hz under signal condition), 01-KeepLast, OP_FORS 10-Force60Hz, 11-Auto (50Hz under no signal condition) 1: The former mode before power-off when power-on OP_AV_ON 0: TV mode when power-on Fixed to Channel 1 when power-on Activated with OP_HOTEL_ON_PROG...

  • Page 15: Structure And Chassis Function Description

    STRUCTURE AND CHASSIS FUNCTION DESCRIPTION 1. Structure Block Diagram IF Pre- From Amplifier Antenna Tuner A100 YUV In SAWF AV I/O Analog switch HEF4053 (N350) Band 1, 2 Vt, AGC C BUS EEPROM Drive TDA6107Q TDA9384/CH05T1610 (N100) AT24C08 (NY01) (N200) V.OUT V.OUT H.

  • Page 16: Block Diagram For Supply Voltage System

    2. Block Diagram for Supply Voltage System...

  • Page 17: Chassis Description

    3. Chassis Description General Description CH-16 chassis is applied in PF2939S, which mainly uses Philips’ advanced UOC-ultimate one chip TDA938X and I C-bus controlled IC. With combination of microcontroller and small signal processor, the TDA938X features high-integrity, high-performance-to-price ratio and high-reliability and advanced functions with fewer external components, which provide much more convenience for manufacturing and technical service.

  • Page 18: Service Data

    SERVICE DATA 1. Technical Data of Key ICs 1.1 Microcontroller and Small Signal Processor TDA935X/6X/8X (1) General Description The various versions of the TDA935X/6X/8X PS/N2 series combine the functions of a TV signal processor together with a -Controller and US Closed Caption decoder. Most versions have a Teletext decoder on board.
  • Page 19 Horizontal and vertical geometry processing Horizontal and vertical zoom function for 16:9 applications Horizontal parallelogram and bow correction for large screen picture tubes Low-power start-up of the horizontal drive circuit µ-Controller 80C51 µ-controller core standard instruction set and timing 1 µs machine cycle 16 - 128Kx8-bit late programmed ROM 3 - 12Kx8-bit DATA RAM (shared between Display, Acquisition and Auxiliary Ram) Interrupt controller for individual enable/disable with two level priority...
  • Page 20 Scrolling of display region Variable flash rate controlled by software Enhanced display features including overlining, underlining and italics Soft colors using CLUT with 4096 color palette Globally selectable scan lines per row (9/10/13/16) and character matrix [12x10, 12x13, 12x16 (VxH) ] Fringing (Shadow) selectable from N-S-E-W direction Fringe color selectable Meshing of defined area...
  • Page 21 (3) Block Diagram...
  • Page 23 (4) Pining (5) Refer to Table 12 about Functions and Data of the IC’s Pins.
  • Page 24 1.2 Triple 2-Channel Analog Multiplexer/Demultiplexer HEF4053 (1) Description With ( ) LOW, one of the two switches is The HEF4053 is a triple 2-channel analog sele cted (lo w impedance ON-state) by Sn. multiplexer/demultiplexer with common With HIGH, all switches are in the high enable input Each...
  • Page 25 Pinning Y0A to Y0C Independent inputs/outputs to Y Independent inputs/outputs to Sc Select inputs Enable input (active LOW) Fig. 11 Pinning Diagram to Z Common inputs/outputs (3) Function Table Inputs Channel EF4053P(N): 16-lead DIL; plastic (SOT38-1) EF4053D(F): 16-lead DIL; ceramic (cerdip) none (SOT7 Notes...
  • Page 26 1.3 2×8W Stereo BTL Audio Output Amplifier with DC Volume Control TDA7057AQ (1) Features (2) General Description DC volume control The TDA7057AQ is a stereo BTL output amplifier Few external components with DC volume control. The device is designed Mute mode for use in TVs and monitors, but is also suitable for Therm al protection...
  • Page 27 1.4 DC- coupled Vertical Deflection circuit TDA8356/N6 (1) F eatures Few external components ighly efficient fully DC-coup led vertical outpu t bridge circuit Vertical flyback switch Guard circuit Protection against: Short-circuit of the output pins (7 and Short-circuit of the output pins to Vp emperature protection High EMC immunity because of common mod e inputs...
  • Page 28 (4) Pinning Fig.15 Table 8 Symbol Description Input power-stage (positive); includes II signal bias drive(pos) (sb) Input power-stage (negative); includes II signal bias drive(neg) (sb) Operating supply voltage Output voltage B O(B) Ground Input flyback supply voltage Output voltage A O(A) Guard output voltage O(guard)
  • Page 29 1.5 Universal Hi-Fi Audio Processor for TV TDA9859 Audio surround decoder can be added (1) Features externally Multi-source selector switches six AF Two general purpose logic output ports inputs (three stereo sources or six mono C-bus control of all functions. sources) (2) General Description Each of the input signals can be switched...
  • Page 30 1.6 Switch-mode Power Supply STR- F6454R/F6656 he Series STR- F6454R/F6654 is specifically designe d to satisfy the requirements for increase tegration and reliability in off-line quasi-r esonant fly back converte rs. The series incorporates a high -precise error amplifying control and d rive circuit with discrete avalanche-rated power MOSFET, featuring fewer external components, small-size and standard power supply.
  • Page 31 (2) Circuit Block Diagram Fig. 17 (3) Pin Configuration and Functions Dwg MK-003-50mm Fig. 18...
  • Page 32 Table 9 Pin Function for STR-F6454R/F6656 Symbol Function Description OCP/FB Over-current protection detection signal/ voltage-limiting signal input MOSFET source MOSFET drain Supply voltage input for control circuit Ground...
  • Page 33 1.7 Triple Video Output Amplifier TDA6108JF/6107Q (1) Features (2) General Description Typical bandwidth 9.0MHz (for The TDA6107Q/6108JF includes three video TDA6108J F) or 5.5MHz (for TDA6107Q) output amplifiers in one plastic DIL-b ent-SIL for an output signal of 60 V (peak-to-pea 9-pin medium power (DBS9MPF) package (SOT value) 111-1), using high-voltage DMOS technology,...
  • Page 34 Table 11 Pinning Symbol Description Inverting input 1 i(1) Inverting input 2 i(2) Inverting input 3 i(3) ground (fin) Black-current measurement output Supply voltage Cathode output 3 oc(3) Cathode output 2 . 20 Pin Co nfiguration. oc(2) Cathode output 1 oc(1) (5) Refer to Table 17 about Functions and Data of the IC’s Pins.
  • Page 35 .8 EEPROM AT24C08 (1) Features Data EEPROM internally organized as 1024/2048 (2) Pin Configuration bytes and 64/128 pages×16 bytes Page rotection mode, flexible page-b page hardware write protection - Additional protection EEPROM of 64/128 bits, 1 bit per data page - Protection setting for each data page by writing its protection bit - Protection management without switching WP in...

  • Page 36: Waveforms Of Key Points

    2. Waveforms of Ke y Points 1-TDA938X-PIN4 2-TDA938X-PIN5 3-TDA938X-P 4-TDA938X- PIN8 5-TDA938X-PIN22 6-TDA938X-PIN26...
  • Page 37 7-TDA938X-PIN31 8-TDA938X-PIN33 -TDA938X-PIN34 10-TDA938X-PIN38 11-TDA938X-PIN40 12-TDA938X-PIN42...
  • Page 38 13-TDA938X-PIN44 14-TDA938X-PIN49 15-TDA938X-PIN58 16-Horizontal Flyback Pulse 17-Waveform of Line Drive Voltage 18-Waveform of Horizontal Scan Current 19-Waveform of Vertical Scan Current...

  • Page 39: Service Data Of Key Ics

    . Service Data of Key ICs Table 12 Functions and Service Data of TDA9384 (N100)’s Pins Digital Multimeter Victor DT890D Function Description Reference Voltage Positive Resistance Negative Resistance Pin No. (K ) (K ) P1.3/T 6.63 6.58 6.64 P1.7/SDA 6.59 6.63 P2.0/TPW 19.02...
  • Page 40 AUDEEM/SIFIN1(1) AUDEEM/SIFIN1(1) 3.77 3.77 21.42 21.42 27.44 27.44 DECSDEM/SIFIN2(1) 3.96 8.25 20.45 26.76 VSSA 2.42 21.54 27.5 SECPLL SNDPLL/SIFAGC(1) 2.42 21.8 27.58 AVL/SNDIF/REF0/AMOUT(1) 0.13 20.2 26.23 HOUT 16.08 24.39 FBISO 0.73 20.3 26.33 AUDEXT/QSSO/AMOUT(1) 3.72 22.04 27.46 AUDEXT/ 1.98 8.48 8.66 QSSO/AMOUT(1) 2.44...
  • Page 41 OSCGND XTALIN 16.83 31.63 XTALOUT 16.73 27.8 RESET VDDP 0.62 0.63 P1.0/INT1 0.03 13.12 13.47 P1.1/T0 0.03 13.15 13.62 P1.2/INT0 16.45 19.94 Table 13 Functions and Service Data of HEF4053 (N350 )’s Pins Digital Multime Victor DT890D Function Desc ription Reference Voltage Positive Resistance Negative Resistance...
  • Page 42 Table 1 4 Functions and Service Data of TDA7057AQ (N600)’s Pins Digital Multimeter Functi on Description erenc e Voltage Positive Resistance Negati ve Resi stance Pin No. (20K ) Volume control input 7.05 7.05 Not connected Audio R signal input 23.54 54.61 upply voltag...
  • Page 43 Table 16 Functions and Service Data of TDA9859(N606 )’s Pins Digital Multimeter: Victor DT890D nction Description ference Voltage ositive Resistance egative Resistance Pin No. (K ) (K ) Audio input 7.75 Output 1 0.19 Audio input 0.46 27.73 Reference volta ge for filtering 7.63 7.39...
  • Page 44 Mode address selection Audio output 3.85 21.24 27.1 Audio compensation 1 3.84 12.29 27.84 Audio input 7.64 1.31 Audio compensation 1 3.84 22.32 27.4 Audio input 3.84 20.45 28.58 Output 2 4.55 7.54 7.54 Audio input 3.84 20.52 27.56 able 17 Functions and Service Data of TDA6107Q/TDA6108JF (NY01)’s Pins Digital Multimeter Function Description...

  • Page 45: Replacement Of Parts

    REPLACEMENT OF PARTS . De ription Many electrical and mechanical components in this chassis have special safety-related characteristics. Components which have these special safety characteristics in t his m anual its supplements are identified by the inte rnational haza rd sym bols or UL, FCC, FDA or marking on the circuit diagram and parts list.

  • Page 46: Appendix

    APPENDIX DIAGRAM CIRCUIT JUC.820.644 JUC.820.725 JUC.820.591 JUC.820.975...

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