Teac-MV-1421-Service-Manual电路原理图.pdf

SERVICE MANUAL MV1421 / 1422 / 4822 34cm / 48cm Televideo Effective: December, 1999 MV4822SERV RadioFans.CN 收音机爱 好者资料库 Chassis CP-420 DVT14F6H DVT14F6HA DVT20F6HA TABLE OF CONTENTS 1. SPECIFICATIONS . 1 2. SAFETY INSTRUCTION. 3 3. BLOCK DIAGRAM. 4 4. ALIGNMENT INSTRUCTIONS. 7 5. SERVICE REMOCON DIAGRAM. 11 6. IC DESCRIPTION. 14 7. CIRCUIT DESCRIPTION . 40 8. VOLTAGE CHARTS. 48 9. PRINTED CIRCUIT BOARDS. 52 10. TROUBLE SHOOTING CHARTS. 54 11. ELECTRICAL PARTS LIST. 69 12. THE DIFFERENT PARTS FOR SIZE . 101 13. THE DIFERENT PARTS FOR SYSTEM. 103 RadioFans.CN 收音机爱 好者资料库 1 1. SPECIFICATIONS 1-1. TV PART TV STANDARDPAL B/G (F. FA MODEL), PAL BIG SECAM-L(L. LA MODEL) PAL I (P.PA MODEL) PAL/SECAM B/G D/K (D. DA MODEL) SCREEN SIZE14 : 34cm (A34JLL90X) 20 : 48cm (A48JLL90X) 21” : 51cm (A51EAL55X01) MAIN VOLTAGE230V AC 50Hz, 110250V AC 50Hz(DA MODEL) POWER CONSUMPTION STAND BY MODE : BELOW 3 Watts OPERATION MODE : 14 = 68 Watts 20 = 78 Watts 21” = 88 Watts SOUND OUTPUT1.5 Watts ( at 60% mod. , 10% THD ) SPEAKER3 Watts 16 Ohm ANTENNA IMPEDANCE 75 Ohm unbalanced input TUNING SYSTEMFS ( FREQUENCY SYNTHESIS ) TUNING RECEPTION CHANNEL UNIT VHF-L : E2 - S7 VHF-H : S8 - S36 UHF : S37 - E69 MEMORY CHANNEL70 PROGRAMS AUX. TERMINAL RCA TYPE AV INPUT JACK HEADPHONE JACK ( 3.5mm? ) REMOTE CONTROLLER R-35 with 2 AA type batteries TELETEXT8page memory TOP and FLOF - West option : German/Deutch/Flemish,French,Italian, Spanish/Portuguese,Swedish/Finnish/Danish,Czech/Slovak -East option : Polish,Czech/Slovak,Rumanian,Hungarian,Servocroat German/Deutch/Flemish,French,Italian -Turkish option : Turkish,English,German/Deutch/Flemish,French, Italian,Spanish/Portuguese,Swedish/Finnish/Danish -Cyrillic option : Russian,Lettish/Lithuanian,Estonian,Ukranian, Czech/Slovak,Servocroat,English OTHER FEATUREON SCREEN DISPLAY,SLEEP TIMER,ON/OFF TIMER AUTO TUNING CHILD LOCK TELETEXT PICTURE TYPE SELECTION 2-TUNER,TV/AV WEIGHT14” : 13.8kg(set) 20” : 23.6kg(set) 21” : 26.2kg(set) 2 1-2. VCR PART * Design and specifications can be subjected to change without notice. CHANNEL COVERAGE IN/OUTPUT JACK TYPE GENERALtemperature 5? 35?(operating) -20? 60? (storage temperature) formatstandard tape width12.65 mm tape speedSP : 23.39mm/sec LP : 11.70mm/sec max. recording time with fullsize cassette SP : 240min. with E-240 video cassette LP : 480min. with E-240 video cassette AUDIOrecording systemlongitudinal track input-3.8dBm(500mVrms), more than 47Kohms, unbalanced. output-3.8dBm(500mVrms),less than 1Kohm, unbalanced frequency range100Hz to 8KHz signal to noise ratio40dB(more than) VIDEOsignal systemPAL/SECAM colour and CCIR mono chrome signals, 625lines/50fields. recording system Rotary 2-head herical scan with a slant double azimuth combination video head. input1Vp-p, 75 ohms, unbalanced output1Vp-p, 75 ohms, unbalanced signal to noise ratio45dB with NETTETE IMAGE control at center position. horizontal resolution240 lines with NETTETE IMAGE control at center position SYSTEMPAL,SECAM-B/G PAL-I/I PAL,SECM-B/G,DK HYPER BAND PAL,SECM-B/G HYPER BAND PAL-IOAK-B/H CHANNELVHF ch 2 - 12 UHF ch 21 - 69 CATV ch X,Y,Z,S1-S41 VHF ch 2 - 12 UHF ch 21 - 69 CATV ch X,Y,Z,S1-S41 UHF ch21 -69VHF LOW ch 1A- 5 VHF HIGH ch 5A-N11 UHF ch 21 - 69 MODELEUROPEMIDDLE EAST,ASIA,CIS AUSTRALIA JACK TYPESCART TPYE the high pass filter cut off frequency is then approximately 3kHz. 11Y/CVBS INPUTThe Y S-VHS signal of 1Vpp (inclusive sync amplitude) is AC coupled to pin11. 12 37 MAIN POSITIVE SUPPLY The TDA8374A has a main supply pin 12 and a hprizontal supply pin 37. Both pins have to be supplied simultaneously. Notice that the IC has not been designed to use this pin 37as start pin. (pin 37 supplies the horizontal oscillator, PHI-1 and PHI-2) (pin 12 supplies the rest of the circuits in th IC) The nominal supply voltage is 8V. With min/max values of 7.2-8.8V. Also in stand-by condition th IC must be supplied with 8V. 22 A Voltage detection circuit is connected to both pins. - pin12 if V12 < 6.8V than a power on reset, POR. is generated. The Hout output is disabled immediate. - pin37 if V37 4V IE1=X OSD can be inserted at the RGB out pins. 27LUMINANCE INPUTAn nominal input signal amplitude of 1V black-white MUST be DC coupled. 50PF;clamping action occurs during burstkey period. 28LUMINANCE OUTPUT The luminance output signal is approximately 1V black-white with typical output impedance of 250 ohm. NONAMEDESCRIPTION 23 29 30 R-Y OUTPUT B-Y OUTPUT The maximum output impedance of pins 29,and 30 is 500? when PAL/NTSC signals are identified. When SECAM is identified by the SECAM add-on and no PAL/NTSC is already identified by the ASM, then the ASM sets the -(R-Y)/-(B-Y) output switch open (via DEMSW). This enables the -(R-Y)/-(B-Y) outputs of the TDA8395 to be directly connected to pins 29 and 30 respectively. 31 32 B-Y INPUT R-Y INPUT The -(B-Y), -(R-Y) output signals (supplied from baseband delay line) are AC coupled, via a coupling capacitor of 10nF or greater, to the -(B-Y)/ - (R-Y) inputs; both inputs are clamped during burstkey period. 33SECAM REF OUTPUTThe SECAM reference output is directly connected to pin 1 of the TDA8395 for SECAM decoding;it also can be used as a reference for comb. filter application. 34 35 X-TAL 3.58 X-TAL 4.43 To ensure correct operation of both: - colour processing internal circuits, - sync calibration internal circuits, it is only allowed to have 3.6MHz X-tals on pin34: both 4.4MHz, 3.6MHz X-tals are allowed on pin 35. If pin35 is not used:then it is left open in application(also XA, XB=0,1). 36LOOP FILTER BURST PHASE DETECTOR One of the important aspects of the PLL is the loop filter connected to pin 36; it influences the dynamic performance of the loop. 38CVBS OUTPUTThe output amplitude is 1Vpp (transfer gain ratio between CVBS 1int or CVBS2ext or CVBS3ext/Y S-VHS and CVBSout is 1). The maximum output impedance is 250. 39BLACK PEAK HOLD CAPACITOR For the correct working of the black stretcher an external time constant should be added at the black peak hold capacitor input. 40 HOR OUTPUTThis open collector output is meant to drive the horizontal output stage. The output is active low,i.e. the line transistor should conduct during the low period of the output. 41SANDCASTLE OUTPUT /FLYBACK INPUT Pin 41 is a combined input/output pin. The pin provides a three level sandcastle pulse. Both burstkey pulse and vertical blanking pulse are always available, the line blanking pulse is only present when the external flyback pulse is fed to this pin. The line flyback pulse, fed to this pin is used for two functions - input signal for the PHI-2 loop - RGB line blanking. (without flyback pulse blanking occurs only during the burstkey pulse) To ensure correct working of the delay line and SECAM add-on, the output should not be loaded with more than : - Sandcastle input delay line TDA 4665 - Sandcastle input SECAM add-on TDA 8395 42PHI-2 FILTER/The loop filter is a first order filter. FLASH PRODECTThis pin requiresa capacitor(C) only. A flash protection becomes active when this pin is forced6V. The horizontal drive is switched-off immediately. Once the voltage is 2mA sink current) Source select switch TDA8374 input switch can select one of the following sources; pin 13 front-end : CVBS1int pin 17 : CVBS2ext pin 11,10 : S-VHS Y,C Selected signal is available at the CVBS output pin38, in case of Y/C input Y+C are added. It drive teletext and the TDA8395 SECAM add-on. For S-VHS applications, the Y,C input can be selected, independent of the CVBS source switch. TDA8374 Y,C inputs are selected,while the source switch outputs CVBS Iint or CVBS 2ext on CVBSout. 7-3. Horizontal synchronization and protection The sync. seperator adapts its slicing level in the middle between top-sync and black level of the CVBS signal. The seperated sync. pulses are fed to the first phase detector and to the coincidence detector. The ?-1 loop gain is determined by the components at pin 43 (C+RC). The coincidence detector detects whether the horizontal line oscillator is synchronized to the incomming video. The line oscillator is a VCO-type, running at twice the line frequency. It is calibrated with the X-tal oscillator frequency of the colour decoder and has a maximum deviation of 2% of the nominal frequency, so no alignment is needed. Calibration is done at start up(the TDA8374 must first know what colour X-tals are connected,bit XA,XB) after synchronization loss (?-1 coincidence detector Sync Locked bit SL). 41 The second phase detector ?-2 locks the phase of the horizontal drive pulses at output pin 40 to the horizontal flyback pulse at input pin 41. This compensates for the storage time of the horizontal deflection transistor. The ?-2 loop filter (C) is externally connected to pin 42. The horizontal phase can be given a static off set via IIC bus (HSH horizontal shift). A dynamic correction is possible by current feedback into the ?-2 loop filter capacitor. To protect the horizontal deflection transistor, the horizontal drive is switched off immediately when a power failure (Power-On Reset bit POR) is detected. The power failure may have corrupted the contents of the internal data registers, so the TDA8374 should be started up again. The TDA8374 has a separate supply input (pin 37) that only used as a clean supply voltage for the horizontal oscillator circuits. 7-4. Vertical Synchronization The vertical sawtooth generator drives the vertical output. It uses an external capacitor at pin51 and a current reference resistor at pin 52. The TDA8374 vertical drive has differential current outputs for DC-coupled vertical output stage, like the TDA8356. At TDA8356 input pins1 and pin2 this current is converted into a drive voltage via a resistor. 7-5. Geometry processing With the TDA8374 is possible to implement automatic geometry alignment, because all parameters are adjusted via the IIC bus. The deflection processor of the TDA8374 offers the following five controls; - Horizontal shift - Vertical slope - Vertical amplitude - Vertical s-correction - Vertical shift 7-6. Colour decoder The colour decoder contains an alignment-free X-tal oscillator, a dual killer and difference demodulators. Together with the TDA8395 SECAM add-on a multi standard PAL/SECAM/NTSC decoder can be built with automatic reconition. Which standard can be decoded depends on the external X-tal used. Two X-tal pins (34 and 36) are present so normally no external switching is required. The IC must be told which X-tals are connected (bit XA and XB). This is important, because the X-tal frequency of the colour decoder is also used to calibrate many internal circuit. The burst phase detector locks the X-tal oscillator with the chroma burst signal. The phase detector operates during the burst key period only, to prevent disturbance of the PLL by the chroma signal. Two gain modes provide: - Good catching range when the PLL is not locked. - Low ripple voltage and good noise immunity once the PLL has locked. 42 The killer circuit switches off the R-Y and B-Y demodulators at very low input signal conditions (chroma burst amplitude). A hysteresis prevents on/off switching at low,noisy signals. 7-7. Integrated video filters The TDA8374 has alignment-free internal luminance delay, chroma bandpass and chroma trap. They are implemented as gyrator circuits tuned by tracking to the frequency of the chroma X-tal oscillator. The chroma trap in the Y signal path is by-passed when Y/C input is selected (S-VHS). For SECAM an extra luminance delay is build-in, for correct delay of the luminance signal. RGB output and black current stabilization The colour difference signals (R-Y, B-Y)are matrixed with the luminance signal(Y) to obtain the RGBout output signals (pins 19, 20, 21). In the TDA8374 the matrix type automatically adapts to the decoded standard (NTSC, PAL). Linear amplifiers are used to interface external RGB in signals (pins 23, 24, 25) from the SCART connector. These signals overrule the internal RGB signals when the data insertion pin 26(FBI) is switched to a level between 1.0V and 3.0V. The contrast and brightness control and the peak white limiter operate on both internal and external RGB signals. R,G,B each have there own, independent gain control to compensate for the difference in phosphor efficiencies of the picture tube : so called white point adjustment. The nominal amplitude is about 2V black to white, at nominal input signals and control settings. TDA8374 has a black current stabilization loop, that automatically adjust the black level to the cut-off voltage of the picture tubes three gun cathodes. Since no current is following when the voltage the cathode is equal to the cut-off voltage of the tube, the loop stabilizes at a very small gun current. This black current of the three guns is measured internally and compared with a reference current, to adjust the black level of RGBout. The black level loop is active during 4lines at the and of the vertical blanking. In the first line the leakage current is measured (max.acceptable 100?). In the next three lines the black levels of the three guns are adjuster. The nominal value of the black current is 10?. The ratio of the black current for the 3guns tracks automatically with the white point adjustment, so the back-ground colour is the same as the adjusted white point. At switch-on of the TV receiver the black current stabilization circuit is not yet active and RGBout are blank