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Changhong Electric 21NF55 Service Manual Download Page 1

 

    

 

FILE NO. SM-CTV-O-131 

 

 

 

 

COLOR TELEVISION 

 

 

SERVICE MANUAL 

 

 

MODEL NO. 21NF55/21PF93 

CHASSIS NO. EX-1A1 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Please read this manual carefully before service 

 

Summary of Contents for 21NF55

Page 1: ...FILE NO SM CTV O 131 COLOR TELEVISION SERVICE MANUAL MODEL NO 21NF55 21PF93 CHASSIS NO EX 1A1 Please read this manual carefully before service...

Page 2: ...UP ADJUSTMENTS 5 CIRCUIT ADJUSTMENTS 8 STRUCTURE AND CHASSIS FUNCTION DESCRIPTION 14 STRUCTURE BLOCK DIAGRAM 14 BLOCK DIAGRAM FOR SUPPLY VOLTAGE SYSTEM 15 CHASSIS DESCRIPTION 16 SERVICE DATA 17 TECHNI...

Page 3: ...25MHz UHF C13 C57 471 25 863 25MHz Receiving channel CATV Z1 Z7 111 167MHz Z8 Z35 223 447MHz Programs preset 236 0 235 Antenna input 75 unbalanced Picture tube Approx Effective screen d imensions 406...

Page 4: ...TV may result in changes in the nominal EHT voltage of the CRT anode So ensure that the maximum EHT voltage does not exceed the rated value after service and adjustment SAFETY PRECAUTION WARNING REFER...

Page 5: ...ned by using replacements rated at higher voltages or wattage etc Components which have these special safety characteristics in this manual and its supplements are identified by the international haza...

Page 6: ...l safety related characteristics MAINTENANCE 1 Install the TV set on a stable and level surface Do not place the set near or over a radiator or heat register or where it is exposed to direct sunlight...

Page 7: ...set 1 3 Operate the TV for at least 15 minutes 1 4 Degauss the TV set using a specific degaussing coil 1 5 Set the brightness and contrast to maximum 1 6 Counter clockwise rotate the R B low brightnes...

Page 8: ...nter of the screen 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 sup...

Page 9: ...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 a...

Page 10: ...ltage Adjustment Caution B voltage has close relation to high voltage To prevent X ray radiation set B voltage to the rated voltage 2 1 Make sure that the supply voltage is within the range of the rat...

Page 11: ...ser service mode adjustment can be changed only when service personnel adjust the whole set data during servicing As the control data have dramatic effects on functions and performance of the TV servi...

Page 12: ...zoom for large screen only 20 Red gun cutoff voltage GRN 20 Green gun cutoff voltage WPR 1F Red gun drive voltage WPG 1F Green gun drive voltage WPB 1F Blue gun drive voltage YDFP YDFN 07 PAL brightn...

Page 13: ...e data sheet may differ dependent on different models The data sheet may differ dependent on different CRTs for the same model 6 3 Option set With remote control system software TDA935X all options ca...

Page 14: ...H French 1 5 OP_GERMAN German 1 6 OP_ITALY Italian Indonesian or Hungarian 1 OP3 7 OP_SPANISH Spanish Malay or Croatian 1 0 OP_FMWS Window selection of sound pll small large window 0 1 OP_DIRECT_SWIT...

Page 15: ...OP_BSCREEN Black screen when changing channels 1 Yes 0 No 1 3 OP_SECAM SECAM color system option 1 Yes 1 4 OP_DFL Disable flash protection 1 5 OP_SIF External SIF amplifier 1 Yes 0 No 1 6 OP_EXT_SIF0...

Page 16: ...4C08 Audio Prec essor TDA7449 H Drive V OUT TDA8356J Audio Amp lifier TDA7057AQ H OUT FBT T402 Power Supply Circuit STR F6654 or STR G5653 3 3V 5V 1 15V 115V CRT Audio Video Input Output Band 1 2 Vt A...

Page 17: ...1 8V 5V 2 To A100 VD891 115V To N600 VD881 15V H VD871 15 S 5V 1 To H Out EEPROM R C Input 3 3V To N100 Keyboard Switch Transformer T804 Power Regulation and Control Circuit STR G5653 F6654 Bridge Rec...

Page 18: ...and advanced functions with fewer external components which provide much convenience for manufacturing and technical service 2 The EX 1A1chassis series mainly use the following ICs and assemblies Tab...

Page 19: ...ith 64 pins The features are given in the following feature list The differences between the various ICs are given in the table on page 4 2 Features TV signal processor Multi standard vision IF circui...

Page 20: ...X 6X 8X PS N2 series Controller 80C51 controller core standard instruction set and timing 1 s machine cycle 16 128Kx8 bit late programmed ROM 3 12Kx8 bit DATA RAM shared between Display Acquisition an...

Page 21: ...t colours using CLUT with 4096 colour 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 colo...

Page 22: ...SERVICE MANUAL 20 3 Block Diagram Fig 7 Block Diagram for TDA935 6 8 PS N2 with Mono Intercarrier Sound Demodulator...

Page 23: ...SERVICE MANUAL 21 Fig 8 Block Diagram for TDA935 6 8 PS N2 with QSS IF Sound Channel...

Page 24: ...ng AVL EWD 1 20 Automatic Volume Levelling East West drive output VDRB 21 vertical drive B output VDRA 22 vertical drive A output IFIN1 23 IF input 1 IFIN2 24 IF input 2 IREF 25 reference current inpu...

Page 25: ...1 32 35 and 44 is dependent on the IC version mono intercarrier FM demodulator QSS IF amplifier and East West output or not and on some software control bits The valid combinations are given in table...

Page 26: ...SERVICE MANUAL 24 Fig 9 Pin Configuration SDIP 64...

Page 27: ...on Two wire serial interface bus I2 C Bus compatible Filtered inputs for noise suppression with Schmitt trigger Clock frequency up to 400 kHz High programming flexibility Internal programming voltage...

Page 28: ...2 General Description The TDA8356 is a power circuit for use in 90 and 110 colour deflection systems for field frequencies of 50 to 120 Hz The circuit provides a DC driven vertical deflection output...

Page 29: ...nnected to an independent input output Y0 and Y1 and the other side connected to a common input output Z With E LOW one of the two switches is selected low impedance ON state by Sn With E HIGH all swi...

Page 30: ...ate the more positive voltage L LOW state the less positive voltage X STATE is immaterial Fig 21 Schematic Diagram One Switch Fig 16 Ratings Limiting values in accordance with the Absolute Maximum Sys...

Page 31: ...tected on all pins 2 General Description The TDA7057AQ is a stereo BTL output amplifier with DC volume control The device is designed for use in TVs and monitiors but is also suitable for battery fed...

Page 32: ...ol In 1 0dbsteps for balancefacility independent mute function All function are programmable via Serial bus 2 descripion The tda7449 is a volume tone bass and treble Balance left right processor for q...

Page 33: ...SERVICE MANUAL 31 4 Pin Connection Fig 19 5 Electrical Characteristics...

Page 34: ...VS 9V RL 10K RG 600 all controls flat G 0dB unless otherwise specified NOTE1 1 The device is functionally good at Vs 5V a step down on Vs to 4V does t reset the device 2 BASS and TREBLE response The...

Page 35: ...units Cycle by cycle current limiting under voltage lockout with hysteresis over voltage protection and thermal shutdown protects the power supply during the normal overload and fault conditions Low c...

Page 36: ...STR F6654 Pin No Symbol Function Description 1 OCP FB Over current protection detection signal voltage limiting signal input 2 S MOSFET source 3 D MOSFET drain 4 VIN Supply voltage input for control...

Page 37: ...SERVICE MANUAL 35 2 WAVEFORMS OF KEY POINTS NI00 Pin58 NI00 Pin33 NI00 Pin34 NI00 Pin44 NI00 Pin22 NI00 Pin21 BU250 8DX B BSC60H HEAT...

Page 38: ...SERVICE MANUAL 36 Notes The waveforms are only for reference The waveforms may d iffer dependent on different models BCT 4 Pin4 N100 P40...

Page 39: ...0 7 9 3 9 VSSC P 0 0 0 10 P0 5 0 01 13 3 13 3 11 P0 6 4 2 11 6 11 0 12 VSSA 0 0 0 13 SECPLL 2 3 27 6 21 7 14 VP2 8 0 1 8 1 8 15 DECDIG 5 0 23 1 16 1 16 PH2LF 3 2 27 5 21 0 17 PH1LF 3 9 27 9 21 2 18 GN...

Page 40: ...2 5 1 1 1 1 53 BO 2 4 1 1 1 1 54 VDDA 3 2 11 0 11 3 55 VPE 0 0 0 56 VDDC 3 2 11 0 11 3 57 OSCGND 0 02 58 XTALIN 59 XTALOUT 60 RESET 0 0 0 61 VDDP 3 2 11 0 11 3 62 P1 0 INT1 0 63 P1 1 T0 1 5 3 3 3 3 64...

Page 41: ...Service Data of HEF4053BP N402 s Pins Digital Multimeter Victor DT890D Pin No Functiondescription Reference Voltage V Positive Resistance K Nerative Resistance K 1 Signal input 3 0 22 2 47 0 2 Signal...

Page 42: ...5 28 0 17 TREBLE R 4 0 30 5 28 0 18 DIG_GND 0 0 0 19 SCL 3 4 6 8 6 7 20 SDA 3 1 6 8 6 7 Notes The data are only for reference The data sheet may differ dependent on different models Digital Multimeter...

Page 43: ...this manual and its supplements are identified by the international hazard symbols or UL FCC FDA or VDE marking on the circuit diagram and parts list When replacing any of these components substitute...

Page 44: ...arbon film resistor RT13 0 166W 100 J R251A Carbon film resistor RT13 0 166W 100 J R430A Carbon film resistor RT13 0 166W 100 J RCLM Carbon film resistor RT13 0 166W 100 J RDAM Carbon film resistor RT...

Page 45: ...0 166W 10K J R139A Carbon film resistor RT13 0 166W 10K J R140A Carbon film resistor RT13 0 166W 10K J R141A Carbon film resistor RT13 0 166W 10K J R141B Carbon film resistor RT13 0 166W 10K J R195 C...

Page 46: ...R888A Metal oxide film resistor RY21 0 5W 3 3 J R416 Metal oxide film resistor RY21 0 5W 22 J R505 Metal oxide film resistor RY21 0 5W 1K J R463 Metal oxide film resistor RY21 0 5W 3 3K J R418 Metal o...

Page 47: ...C159 Ceramic capacitor CT1 63V 10a 2B4 4700PFK C621 Ceramic capacitor CT1 63V 10a 2B4 4700PFK C015 Ceramic capacitor CT1 63V 08a 2F4 10nFZ C025 Ceramic capacitor CT1 63V 08a 2F4 10nFZ C026 Ceramic ca...

Page 48: ...citor CL21X 50V 0 22 FJ C623 Polyester film capacitor CL21X 50V 0 22 FJ C009 Polyester film capacitor CL21X 50V 0 47 FJ CBY10 Polyester film capacitor CL21X 50V 0 47 FJ C411 Polyester film capacitor C...

Page 49: ...r CD110X 16V 220 FM C116 Aluminum electrolytic capacitor CD110X 16V 470 FM C414 Aluminum electrolytic capacitor CD110X 25V 220 FM C462 Aluminum electrolytic capacitor CD110X 25V 470 FM C666A Aluminum...

Page 50: ...nductor TEM2000 L421 Feed through inductor TEM2011 L422 Feed through inductor TEM2011 L502 Feed through inductor ZZ008 VD882 Diode W05Z2 7A D895 Diode W05Z4 7B D895 Diode GDZJ4 7B VD448A Diode W05Z8 2...

Page 51: ...51 Triode KTA1266 Y V241 Triode 3DG1815 Y V241 Triode 2SC1815 Y V241 Triode 2PC1815Y V241 Triode KTC3198 Y V201A Triode 3DG1815 Y V201A Triode 2SC1815 Y V201A Triode 2PC1815Y V201A Triode KTC3198 Y V3...

Page 52: ...IC BU2508DX N600 IC TDA7057AQ N401 IC TDA8356 N6 V115 IC L7805CV N442 IC L7808CV N801 Photo coupler CE HS817 N801 Photo coupler CE HPC922 N801 Photo coupler CE HS817C N801 Photo coupler CE SFH615A 3...

Page 53: ...J R300S Carbon film resistor RT13 0 166W 10K J C300S Ceramic capacitor CT1 63V 08a 2F4 10nFZ C313 Polyester film capacitor CL21X 50V 0 022 FJ V300S Triode 3DG1815 Y V300S Triode 2SC1815 Y V300S Triod...

Page 54: ...tor RT13 0 166W 100 J R364 Carbon film resistor RT13 0 166W 100 J R358 Carbon film resistor RT13 0 166W 180 J R354 Carbon film resistor RT13 0 166W 220 J R362 Carbon film resistor RT13 0 166W 220 J R3...

Page 55: ...V247 Triode 2SA1015 Y V247 Triode 3CG1015 Y V247 Triode 2PA1015Y V247 Triode KTA1266 Y V047A Triode RN1204 Z243 Ceramic trap TPS4 5MB2 Z243 Ceramic trap XT4 5MB 7 Parts for SIF R262A Carbon film resis...

Page 56: ...ctor HXT39 JU4 756 032 L505 Horizontal amplitude coil HFT 270 T804 Switch transformer CE BCK 24005L JUB4 726 083 T401 Flyback transformer CE BSC60H JUB4 799 044 1 b Mount the following parts when usin...

Page 57: ...mic capacitor CT81 2KV 14c 2C1 1200PFK C505 Polypropylene capacitor CBB81 1 6KV 9100PFJ C512 Polypropylene capacitor CBB13 400V 0 36 FJ L506 Horizontal linear inductor HXT39 JU4 756 032 L505 Horizonta...

Page 58: ...oxide film resistor RY21 3W 5 6K J C504 Ceramic capacitor CT81 2KV 14c 2C1 1200PFK C505 Polypropylene capacitor CBB81 1 6KV 9100PFJ C512 Polypropylene capacitor CBB13 400V 0 36 FJ L506 Horizontal line...

Page 59: ...0V 0 1 FJ CY06 Aluminum electrolytic capacitor CD110X 250V 10 FM VDY01 Diode 2CK75D VDY01 Diode 1N4148 VDY02 Diode 2CK75D VDY02 Diode 1N4148 VDY03 Diode 2CK75D VDY03 Diode 1N4148 VDY04 Diode BAV21 VDY...

Page 60: ...stor RF11 2W 1 5 J c Mount the following parts when using a BMCC CRT RY20 Fuse resistor RF10 2W 1 5 J RY20 Fuse resistor RF11 2W 1 5 J d Mount the following parts when using a Samsung CRT A51KQK99X01...

Page 61: ...wer Switch PCB RP12 Carbon film resistor RT13 0 166W 1K J RP12A Carbon film resistor RT13 0 166W 1K J RP12B Carbon film resistor RT13 0 166W 1K J VDP11A 1 Light emitting diode HFBA032MP 90S3 VDP11B 1...

Page 62: ...arbon film resistor RT13 0 166W 100 J R251A Carbon film resistor RT13 0 166W 100 J R430A Carbon film resistor RT13 0 166W 100 J RCLM Carbon film resistor RT13 0 166W 100 J RDAM Carbon film resistor RT...

Page 63: ...tor RT13 0 166W 10K J R140A Carbon film resistor RT13 0 166W 10K J R141A Carbon film resistor RT13 0 166W 10K J R141B Carbon film resistor RT13 0 166W 10K J R195 Carbon film resistor RT13 0 166W 10K J...

Page 64: ...0 5W 22 J R505 Metal oxide film resistor RY21 0 5W 1K J R463 Metal oxide film resistor RY21 0 5W 3 3K J R418 Metal oxide film resistor RY21 1W 330 J R881 Metal oxide film resistor RY21 2W 0 2 J R890A...

Page 65: ...F4 10nFZ C025 Ceramic capacitor CT1 63V 08a 2F4 10nFZ C026 Ceramic capacitor CT1 63V 08a 2F4 10nFZ C603 Ceramic capacitor CT1 63V 08a 2F4 10nFZ C064 Ceramic capacitor CT1 63V 08a 2F4 10nFZ C666 Cerami...

Page 66: ...itor CL21X 100V 0 1 FJ C425 Polyester film capacitor CL21X 100V 0 1 FJ C493 Polyester film capacitor CL21X 100V 0 1 FJ C481 Polyester film capacitor CL21X 250V 0 1 FJ C801 Polypropylene capacitor CE C...

Page 67: ...ytic capacitor CD110X 25V 1000 FM C872 Aluminum electrolytic capacitor CD110X 25V 1000 FM C882A Aluminum electrolytic capacitor CD110 35V 470 FM C161 Aluminum electrolytic capacitor CD110X 50V 0 47 FM...

Page 68: ...4 7B D895 Diode GDZJ4 7B VD448A Diode W05Z8 2A VD448A Diode GDZJ8 2A D886 Diode W05Z15C D886 Diode GDZJ15C VD890 Diode 2CK75D VD890 Diode 1N4148 VD892 Diode 2CK75D VD892 Diode 1N4148 VD065 Diode 2CK75...

Page 69: ...2SC1815 Y V201A Triode 2PC1815Y V201A Triode KTC3198 Y V371 Triode 3DG1815 Y V371 Triode 2SC1815 Y V371 Triode 2PC1815Y V371 Triode KTC3198 Y V391 Triode 3DG1815 Y V391 Triode 2SC1815 Y V391 Triode 2...

Page 70: ...lator JA18A 12 000MHZ G200 Crystal oscillator 9922 520 00169 12MHz A100 Electronic tuner TDQ 5B6 M JUB2 891 001 1 Z240 Ceramic trap TPS6 5MB Z240 Ceramic trap XT6 5MB Z241 Ceramic trap TPS6 0MB Z241 C...

Page 71: ...ilm resistor RT13 0 166W 100 J RBY1 Carbon film resistor RT13 0 166W 2K J RBY2 Carbon film resistor RT13 0 166W 2K J R631 Carbon film resistor RT13 0 166W 2K J R381 Carbon film resistor RT13 0 166W 2...

Page 72: ...ilm resistor RT13 0 166W 470 J R351 Carbon film resistor RT13 0 166W 3 3K J R356 Carbon film resistor RT13 0 166W 3 3K J R360 Carbon film resistor RT13 0 166W 3 3K J R352 Carbon film resistor RT13 0 1...

Page 73: ...ilm resistor RT13 0 166W 100 J R263 Carbon film resistor RT13 0 166W 220 J R263A Carbon film resistor RT13 0 166W 820 J R264 Carbon film resistor RT13 0 166W 820 J R261A Carbon film resistor RT13 0 16...

Page 74: ...Metal oxide film resistor RY21 0 5W 2 2 J R518 Metal oxide film resistor RY21 2W 1K J R519 Metal oxide film resistor RY21 3W 5 6K J C504 Ceramic capacitor CT81 2KV 12c 2B4 820PFK C505 Polypropylene c...

Page 75: ...6W 6 2K J R411 Metal oxide film resistor RY21 0 5W 2 2 J R412 Metal oxide film resistor RY21 0 5W 2 2 J R518 Metal oxide film resistor RY21 2W 1K J R519 Metal oxide film resistor RY21 3W 5 6K J C504 C...

Page 76: ...tor RT13 0 166W 10K J R482 Carbon film resistor RT13 0 166W 12K J R411 Metal oxide film resistor RY21 0 5W 1 8 J R412 Metal oxide film resistor RY21 0 5W 2 2 J R518 Metal oxide film resistor RY21 2W 1...

Page 77: ...20 J RY17 Carbon film resistor RT14 0 25W 330 J RY18 Carbon film resistor RT14 0 25W 330 J RY19 Carbon film resistor RT14 0 25W 330 J RY40A Carbon film resistor RT14 0 25W 330K J RY11 Metal oxide film...

Page 78: ...VY08 Triode 3DG422 VY05 Triode BF423 VY05 Triode 3CG423 VY07 Triode BF423 VY07 Triode 3CG423 VY09 Triode BF423 VY09 Triode 3CG423 SY01 CRT socket Model GZS series CE GZS10 2 108 SY01 CRT socket Model...

Page 79: ...A51LYZ095X91J RY20 Fuse resistor RF10 2W 3 3 J RY20 Fuse resistor RF11 2W 3 3 J i Mount the following parts when using a Malaysia based Matsushita pure flat CRT A51LYZ095X90 RY20 Fuse resistor RF10 2W...

Page 80: ...uminum electrolytic capacitor CD110X 16V 47 FM 6 Parts on Power Switch PCB VDP11A Light emitting diode HFBA052MP 7 0 7 Others Power switch KDC A04 MU171 Power Cord RVVZ CH4 2000 ZH1 Electric speaker Y...

Page 81: ...Circuit Diagram for 21NF55 21PF93...

Page 82: ...MAIN PCB FOR 21NF55 21PF93...

Page 83: ...CRT RGB PCB FOR 21NF55 21PF93...

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