6.- Electric Diagram - Page de test
Contents
1. QI1O L0 LO COF ct Q Q Q Q v rv v v v v CO CO OO CO CO CO O QOO O O QO O O QO v v v v QOO CO OO CO CN CV CV N CV N CN OV N N N N OV N CV CON N OV OV N QN CO CO CO CO CO CO CO COD CO CO CO CO CO COD CO CO NS sc 2 1X3 nzz GND UNS 0087 2006 9 534 NI QMS I 0985 Sere 2 i 8 9s S N gis Z58 93S EBBE t899 0995 553 Pr AUT LYXS LNI Av 9 87 B amp B LEBE 9 Ziv Lege 859 1X3 84 Say 8789 8 5986 Sano 4 IXI SHAD 89 YU 3843 D5 3845 C5 3850 F2 3851 3852 E2 3853 D3 3854 E2 3855 C3 3856 F2 3858 C3 3860 E4 3865 B2 3875 B4 3876 C4 3877 B4 3879 D2 3880 E2 3881 D1 3883 E1 3891 C2 3893 G3 5061 7 6848 2 6849 2 6851 4 l 600 L CI z EBLE d volt L6LE x OU noot L6LE i PLZ 89 6916 7612 L C5 Nozz M E 022 0616 0612 SFA 1815 Lav 911 i i L 179 49 OGLE y2. OOX lt TO F O00 SF NOON SF QO IO LO F SF LO OON CN CO SF ON CN CO SE Notor r re O CO CO SE OAN N N rr NANN N N N N N C0 CO CO CO C C CO CO CO CO CO CO CO CO CO CO CO CO CO CO LO LO LO LO LO LO OO DK OO OO XO CO co XO co CN N mr n CO oo oo oo OO CN o OO OO CO CO CO CN CO N SF OO SF OON SFO SE OCON O eN CO _ 1000 N s LO C CO rrrrrr rT QN CN QN CO Or SE SF NF 0 10010 r rere
3. OO NOOOOoOOOOQOOQOOQOQQocooopooopoomooopo r N NNN CO CO COO v v rv v eN ON QN T c CN CN CN CON N N N N N N N N N N N N N N N N N N N N N N N CV QN QV CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO PF QN rm s 0 d n 7116 0206 5006 2206 Z06 2106 ano Hano anoano ano eang Noo 1206 L026 7 06 106 622 suctus ou g ri 9 21 1X3 g4 zeg L ZIN 1001 ee 8c ino 8 E 00 9825 0 9 NOOL ccn 1X3 Leg 8 gt 97 76 VOZE 47 622 89M EN NOOL CU 4001 1X3 ino 9 Bussi 92 26272 592 HOLY g 6725 626 oo 00 7 628 _ X001 1x3 8 100 d Gz 1 655 7808 30 7 yoce 879 _ mL OPZE 0 22 HIvoi 8 6825 S LW 7806 34 c POZZ SSAO A LO8Z 89 S8AO 1 3 9 0c 61 BR YL NL spege 7505 AL LNI 58 PEE gl T 5505 NOOL noce 9LOC Goz 8 LL ZHIN6 86 221 Ald wil LNO YHO dWWA LX 45 NI 1X3 1x3 LLNO 58 INO S8AO LNI 331 DOA 14 3vSs lo8 Jvs 108 1nO W3 NV 023 ONASA 6 8 LlH3A 8 8 AHQ
4. 0 See table 11 2450 313010080046 cAe por 250v s See table 11 A 2450 313010080055 POL 250v 5 832053 Seetable 11 A 2500 313010080071 lcaewkpo4mwzmvAc 2502 202055890282 cap ceret an2 vum AN 2504 202055890282 capcerrLanaikvimuratay AN 2505 222205758689 eLEcTR esu sesvewo 2506 313010080068 cap ana 2sovac pvo ANI 2516 202055890282 capcerrLanaikvimuratay LN 2524 202055890335 carcereL poor JA 2524 202055890337 cap ceret 1 iv fian 2534 202055890337 1 407 PARTNUMBER DeSCRITION 0 p forosvosm e520 312010070028 Joios eso 239676010673 esa 312010070029 fron 312010070500 Jc SEC rors fo sze dL rer 525267651112 erem rrer 226260854112 Jio torsos rao st2010070510 jer 7448 ona7eose0 27 fra sur mae 7514 o22204088682 torse 7825 823008007670 EX zeoo 3120100708570 smeer oa 65 15 mmo mem 932006715712 sacon 5 CHASIS IDAG POS PARTNUMBER
5. INP XE 0982 4 ino 25 22 0985 1X3 8 LMP say 8006 42607 OV 1006 E I Say 7 1802 mln 093 SEDE IVA A BM v3 Nee 9002 poj 00 C e 2002 01 LW LL CO Lr82H G B LIBE G Wot 1909 d rm 0 9 6 Electric Diagram 1 POWER SUPPLY 95 A M1 2 5525 90A 2 8 7 FERRITE 95 L 2530 2 e T 47U 6516 2 7577 M13 54 3504 e gt BC337 5 en 12 10M 9598 3524 3520 f T 1 390K 150K 7525 Ferrite 2565 9570 3525 3519 STP2NBOFI T A amp 3577 990 390 150 2 d 6541 1541 8 22R f lt o 390R 6570 T 5 EJ 6573 csv Cin uL S BYD33D T630mAL 1 C5V6 3 SIMU SOFT START J amp Z J fe os ch 2 u REGUL ZERO 3521 5 EEN 2509 12R 2532 5540 3509 gt 11 470P FERRITE 4K7 4 1 1540 3502 7502 8 327 6540 8 5532 2 ge 2563 4 FERRITE 2540 amp A 2200 680U 5STB 2 3 6572 9 2506 9541 o GND1 3N3 A PAL SECAM PAL SECAM BG DK BG I YES STV2248
6. Euroconector 1 Audio 0V5 RMS 1K 17 CVBS 4 2 Audio 0V2 2V RMS 10K 18 CVBS 4 3 Audio gt L 0V5 RMS 1K 19 CVBS 1Vpp75S 4 Audio 4 20 CVBS 1Vpp 75S 5 Blue 4 21 Earthscreen 6 6 Audio L 0V2 2V RMS 10K 0 75 7 Blue 0V7pp 75S E 8 CVBS status 1 0 2 int 10 12V ext o 9 9 Green 4 D 10 o 11 Green OV7pp 75S 2 42 ug o 2 13 Red Head phone 6 15 Red OV7pp 75S 85 to 6005 325 25mW 16 RGB status OV to OVA int 1 3V ext 75S 3 Mechanical instructions For the main carrier two service positions are possible 3 1 A For faultfinding on the component side of the main carrier B For de soldering activities on the copper side of the main carrier Position A can be reached by first removing the mains cord from it s fixation then loosen the carrier lips 1 and then pulling the carrier panel 2 for approximately 10cm Position B can be reached from position A after disconnecting the degaussing cable Put the carrier on the line transformer side Fig 3 1 4 Oscillograms gt 181 E ur S 1081 TP2 D 12V6 DC TP2 5 10V6 DC hiaan A 50V div DC 10ms div Vidiv DC Bus div WidvDC 10us div D TP4 TPS D TP5 20mV div AC 10 us div 20mV div AC 10us div 100V div DC 5us
7. Remote Control 5 system Red Green Blue Random Access Memory Control signal from uC but on DC level via RC network for saturation control of the video controller IC7015 6D Surface Acoustic Wave very precise bandpass filter Sandcastle signal from 7015 6 to delay line 7271 and SECAM chroma decoder 7250 CVBS signal from pin 2 SCART to external input pin 15 IC7015 6B CVBS signal from IF detector IC 7015 6A to pin 19 SCART Audio signal from SCART AV cinches to source select 7140 Audio signal from IC 7140 to pin 1 and 3 SCART AV Euroconnector Clock line of the 2 Data line of the IC bus Service Default Mode predefined mode for faultfinding see chapter 8 SEquential Couleur A Memoire Switched Mode Power Suplly Switching signal low for standby only line is shut high for normal operation Synchronisation Tets point 1 Ultra High Frecuency band from tuning range The DC voltage across C2505 present at pin 11 of the primary side of the transformer Tuning voltage 0 30V 50Hz vertical flyback pulse used for locking the vertical oscillator in IC7015 6E 50Hz vertical flyback pulse from frame 7400 lo lock the OSD generator in uC Vertical drive signal from 7415 6 to frame amplifier 7400 Voltage on Grid 2 of the picture tube Very High Frecuency band from tuning range Control signal from uC but on DC level via RC network for volume control of sound processing in IC7015 6F Volt
8. div 100V div DC 10157 div TP6 14 D 101 5 DC TP6 20 D 103 5 DC TP6 21 D 105 DC D 3V3 DC TP8 D 11 7 DC TP12 D 5Vi div DC 50 us div TP16 D 5V div DC 5ms div TP20 D 100V div DC 2us div TP24 D 1V div DC 500 us div TP29 D 1V div DC 20us div TP35 D 1V div DG 500 us div 0 5V div DC 20 us div TP13 D 5V div DC 20us div TP17 D 5ms div 1Vidiv DC TP21 D 20us div 0 5V div DC TP25 TP26 D 1ms div 0 5V div AC TP30 D 20us div 1V div DC TP36 D 0 5V div DC 10 us div 1V div DC 20 us div TP14 D 200V div DC 20 us div TP18 D div 0 5V div TP22 D 1V div DC 20 us div I2C BUS STV224x TP34 D SCL 37 SDA 2 BUS TDA9875 27 D SCL TP31 D SDA TP32 D 1V div DC BOO Ls div TP38 CD 05V idv DC 20us div TP11 0 1V dvDC 5ms div TP15 D 10V div DC 5ms div TP19 D 20 us div div DC TP23 D 20us div 1V div DC TP28 CD 1Vidiv DC TP33 D 5mV div D
9. is present at C2460 There are the following supply voltages obtained from line transformer 5545 25V To supply frame deflection The heather voltage is reduced by R3235 38 and 5201 02 Diagram B to obtain 6 3Veff at the CRT 7 4 SOUND AMPLIFIER Diagram C Sound amplifier is a Bridge Tied Load BTL amplifier short circuit protection mute and stand by mode IC used can be TDA8941 for 14 and 17 models or TDA8943 for 20 and 21 models TDA8944 is reserved for stereo models not explained in this manual Supply Vcc SVR Main supply Vcc is taken from 11V of Power Supply C2540 diagram D The IC creates internally a half supply present in SVR pin and decoupled by 10uF capacitor Sound input IN This amplifier has a differential input IN IN Audio input is connected to IN decoupled by 220nF capacitor C2186 and IN is decoupled to ground by other 220nF capacitor To avoid oscillations there is a 1n5 capacitor connected between both inputs Mode input This input is commanded by the uC and has three modes depending of the voltage level Standby mode Vmode Vcc Consumption is very low used during stand by Mute mode 2 5V lt Vmode lt Vcc No sound output used when the set is switched on off there is no signal etc Operating mode Vmode lt 0 5V Sound output present normal operation Sound output OUT OUT Amplified sound is drived to the loudspeakers Headphones output has been connected i
10. pEscrenon Eseec 3190 230620703208 _ resnerasH vaweus B 3201 230620403181 weR2s A B 3202 232219473183 respRoziaxawens A B 3203 212010308152 InEscamwco s aw B 3214 230620409181 resNeR2s won vew pms A B 3215 232219473182 resproziaxawens A B 3216 212010308152 InEscamwco us uw LAN B 3226 212010308152 InEscamwco us AN B 3228 212010308152 sescamwco we uw B 3229 212010308152 Rescamwco s vaw B 3293 230620403181 weR2s 10r vowews A B 3234 232219473183 esemonikowews JA B 3235 230620403108 m wowews B 3238 230620403108 2 iR See table t1 A 3238 230620703208 resneR2sH zm wowrws See table 11 A B 3243 232218676102 sFRooH kusweus A B 3406 230620703208 B 3444 232219533562 resrumprossxsaw B 3449 230620703108 uaweus LAN B 3457 230620703279 res 27r vaw ems anm A B 3457 230619703479 resrrotame wens poor A B 3470 230620403478 amr A D 3501 232266206626 IA D 3502 230620703109 Res nerzh vn vawews A D 3504 232224213106 10m vawews JA D 3507 232219473154 resPRozisok2wems LAN D 3516 232219473104 2 D 3523 230620403339 _Reswer
11. STV2248 SEE TABLE 11 PAGE 23 10U 470 SEE TABLE 11 PAGE 23 SEE TABLE 11 PAGE 23 2K4 1K2 27R 47 K2 bo M JMP 10 3503 2K 1 750 L 9506 sce Set uum STANDBY prs 3505 1277 3575 3K 1 470R A B C D E F G H K L _ TIAL 1 25 L 7600 SAA5531 CTS SAA5541 CTS POS 1500 1540 1541 2500 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2514 2515 2516 2522 2523 2524 2530 2532 2534 2540 2561 2562 2563 2564 2565 3500 3501 3502 3503 3504 3505 3507 3508 3509 3510 3512 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3527 3528 3570 3571 3573 3574 3575 3576 3577 5500 5525 5531 5532 5534 5540 5552 6502 6503 6504 6505 6515 6516 6521 6530 6540 6541 6570 6571 6572 6573 6574 7501 7502 7514 7525 7571 7575 7577 9501 9503 9506 9523 9524 9541 9570 9582 9598 9599 6 Electric Diagram 3687 K3 3691 B2 1679 G3 1685 F2 a 3692 B2 2149 E2 SWO sO ODA oo ON Or CN CN CN CN CN A ONNA S mc 19 LO Pl LO t Q
12. Synthesized Tuning system This system works by tuning to a station on the tuner through a linear variation of the tuning voltage V VARI from OV to 33V applied on pin 2 of the tuner It is generated on pin 1 of the uC and converted to an adequate level for the tuner using T7605 While searching uC are always reading AFC Automatic Frequency Control and video identification signals from IC 7015 by I2C bus When video signal is identified uc stops searching and do a fine tuning to reach a right AFC value Factory facility pin5 This pin used only in the factory should be connected to 5V by R3621 Service pin 7 This pin is used to put the set in Service Mode see chapter 8 1 INT EXT input pin 8 The set can switch to external AV on the screen by remote control selecting program 0 or by rise edge at pin 8 of euroconnector see diagram C The uC switches video and audio see 5 1 2 to external via I2C bus In both cases the user can switch to internal changing the channel Control key pin 10 Pin 10 is activated by a DC voltage When control keys are not activated a voltage of 3V3 is produced by divider R3618 and R3619 If a control key is activated a resistor R3665 R3667 are connected in parallel with R3619 decreasing the voltage of pin 10 There are 3 voltage levels depending on value of parallel resistor 1 85V 910R 470R 1V 470R or OV ground circuit Band switching pin 14 15 16 There are outputs for band swi
13. The picTure tube PWB has printed spark gaps Each spark gap is connected between and electrode of the picture tube and the Aguadog coating 10 List of abbreviations uC uP INT EXT AF AFC AGC AM APR AQUA AV BG UDK LL BG L BRI BRIGHTNESS BSW1 BSW2 CONTRAST CRT CVS DC EEPROM EHT FET FF FM HOR FLYBACK HOR HUE IDENT IF LED LOT MUTE PROG 0 NIL NTSC OSD OSD FAST BLANKING OSD G PAL PLL POR POS NEG PP PROT PTC RC5 RGB ROM SATURATION SAW SC SCART CVBS IN SCART CVBS OUT SCART AUDIO IN SCART AUDIO OUT SCART SCL SDA SDM SECAM SMPS STANDBY SYNC TP 1 UHF V IN V VARI VERT FEEDBLACK VERT FLYBACK VERT DRIVE Vg2 VHF VOLUME VST Microcomputer Switching signal from uC to TS7876 and TS7877 diagram C making together with pin 8 of SCART connector the INT EXT switching signal low for internal high for external Alternating Current Automatic Frecuency Control Automatic Gain Control Amplitude modulation Automatic Peak Regulation Aquadag on the CRT panel for spark gaps and used for making BCI signal Audio and Video cinches on the rear side of the set Beam Current Info if beam current increases the BCI signal decrases BCI is used for contrast reduction if beam current is too high Derived from BCI if beam current increases more white EHT decreases so picture will become too big BCI
14. connected to 40 PAL sets SI V2246 is used Bandpass filter and demodulator are fully integrated Demodulator consist of synchronous detectors PLL is locked during the burst gate time window CLPF pin 41 The voltage on this chroma PLL filter controls the VCO in order to have the right frequency and phase according burst signal PAL SECAM sets ST V2248 is used Pal or Secam signals are recognized automatically by the IC Pal decoding is the same as in STV2246 Secam demodulation is based on a PLL with automatic calibration loop Secam bell filter pin 38 Central frequency of bell filter 4 286 MHZ is fine tuning during frame blanking using the XTAL frequency 4 433 MHz as a reference Tuning control voltage is stored in C2270 Chroma DL The outputs of the demodulator are applied to an internal chroma delay line Line number n is delayed 64useg and added to n 1 obtaining U and V signals R Y and B Y 7 1 5 RGB processor External RGB inputs pins 25 26 27 RGB inputs coming from scart see diagram C are AC coupled C2291 92 93 and converted internally in YUV signals RGB TO YUV Then are switched with internal YUV YUV SWITCH by fast blanking Fast blanking external pin 28 When fast blanking is high external RGB is displayed only if TV is in external AV program 0 Fast blanking can switch signals for full screen by a DC voltage or for a part of the screen by a pulse voltage Matrix Afte
15. is processed in SIF circuit QSS system SIF input pins 1 2 Sound is filtered from IF signal in a SAW filter K9650 1137 The IF input is present at pin 1 of 1137 and pin 2 is used as a switching input f Vpin2 OV a 40 40MHz sound carrier is filtered for L system L L signal is high T7127 conducts If Vpin2 Vpin1 a 33 40MHz sound carrier is filtered for L l BG systems L L signal is low T7127 is cut D6115 conducts SIF AGC pin 3 The sound IF AGC time constant is fixed by the capacitor C2024 7 1 2 Sound processor FM demodulation For intercarrier sets no multistandard FM sound is filtered internally from CVBS pin 13 and demodulated De emphasis is also made internally If the set is Pal Secam BG or DK STV2248 is used instead of STV2246 SIF input and AM demodulator are avoided and pins 1 2 are AC grounded by C2115 Scart audio out pin 11 The signal at this pin is drived to the euroconnector sound outputs see Diagram C External audio in pin 14 External audio proceeding of pins 2 6 of euroconnector is applied to this pin Selection between internal or external is done by an internal switching controlled by 2 see INT EXT chapter 7 6 Audio out pin 55 After a volume control by 12C this output is drived to the input IN of the final sound amplifier 7187 Diagram C Multistandard sets FM demodulation This function is done in the same internal circuit of STV2248 that no multi se
16. s and many other semi conductors are sensitive to electrostatic discharges ESD Careless handing during repair can reduce life drastically When repairing make sure that you are connected with the same potential as the mass of the set via wrist wrap with resistance Keep components and tools on the same potential 3 Proceed with care when testing the EHT section and the picture tube 4 Never replace any modules or any other parts while the set is switched on 5 Use plastic instead of metal alignment tools This will prevent any short circuits and the danger of a circuit becoming unstable 6 Upon a repair of a transistor or assembly e g a transistor or IC with heatsink and spring remounting should be carried out in the following order 1 Mount transistor or IC on heatsink with spring 2 Resolder the joints Notes 1 After replacing the microcomputer first solder the shielding before testing the set This is needed as the shielding is used for earth connection If this is not done the set can switch into protection mode see description of the SMPS 2 Do not use heatsink as earth reference 3 The direct voltages and waveforms should be measured relative to the nearest earthing point on the printed circuit board 4 Voltages and oscillograms in the power supply section have been measured for both normal operation and in the stand by mode As an input signal a colour bar pattern has been used 5
17. sear 913 H 285 391 100 99V 1 9 6 H ZNI Ald 2 10S LNI Id 9 T LL0Z 0105 F 118 Line e 5202 ale E dee vas dVO dld 99V ALIN 50 E S T a 1 98 NZZ NOL 8 gus i 9Z0Z E N82 0 1 1 c89vg 1002 LLOE 1 JeJA3l SOG BS J vlog V 3 d ear cts uu es e 21 01 dVO 315 29 S 73 Can Bre Qoi jp e 7 0216 9 1no oan ino oianv ZNI AIS I 6115 g4 289 8 eu iv 08 2 6 900 LIAE i INI 1 VE 5 0 8 1 pF oW ee he GNNOS OAGIAWWONHD Al V 6 Electric Diagram B EC OIM cee Mc EXE eee WS RGB amp DISPLAY COMPONENTS 200 DISPLAY 2005 q 5 i 2 CN IN QAS gl gt 47 9 6243 C8V2 2445 o 11AF 7445 A lt BUT 3445 47R 101 5 6451 BYD33D 2 5441 6 1 726 2 6 7401 1771 RES L2 1 L2 4 12 2 3211 3K9 L2 3 3K9 L2 5 FRAME H FLYBACK 555 200 RGB GND s 25 A31 A16 SE CENE ee 8 2453 470U RGP10G T 2204 2208 2209 2217
18. 2230 2402 2403 2404 2405 2406 2407 2408 2410 2411 2430 2440 2442 2444 2445 2446 2448 2449 2450 2451 2453 2458 2460 2462 2470 3201 3202 3203 3204 3208 3210 3211 3212 3214 3215 3216 3217 3221 3225 3226 3228 3229 3230 3233 3234 3235 3238 3243 3244 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3416 3417 3418 3430 3431 3432 3433 3434 3440 3442 3444 3445 3449 3451 3455 3456 3457 3460 3461 3462 3463 3470 3480 5201 5202 5440 5441 5445 5447 5449 5480 6201 6218 6225 6227 6243 6401 6447 6449 6451 6462 6470 7201 7204 7205 7208 7209 7210 7211 7212 7213 7401 7430 7431 7440 7445 9204 9212 9214 9217 9220 9221 9401 9402 9404 9417 9480 6 Electric Diagram 6852 E4 6853 D4 1001 7 2001 B8 6854 D4 2002 B6 6855 D4 2005 07 TO c CO LO CN 10 LO OYA P LO XO QI C O QI OTA 0000 l st ADA QN xr QI sr 00 00 00 OO 10 CO sb QN LO Odor t QO QI ON
19. 2696 69ECLEWd 701 9696 v0S6 8155 E VS LOL 51 3675 K8 3676 3681 17 3684 D3 3685 D3 EL 11 STV2246 N 38 18 5 ei 3s ini 22 _ 5 a E uad as ion 16 g PIFIN2 7 APR AGCPIFCAP 5 aac 37 FBOSD TUNERAGCOUT 8 TUNER AGC DEMOO i36 ROSD SOUND BP 35 aoso NC 1 d NC 2 gt 1 ee 59 lan T 32 ROUT sc en Mono 5 54 i oad V IF 12 47 VERT GND IF 10 43 5 E 1 5 cpus AUDIO vouume KP A wi DECODER REF sh GND2 19 Y 5 5 y 4 40 41 a2 sais 8 ossvan 2 wi NIOIOnv LX3 STV2248 Scu panes LAOH Sela TX Figure 7 1 TV Processor block diagram 7 CIRCUIT DESCRIPTION 7 1 SMALL SIGNAL PROCESSING Diagram A The small signal is processed by IC 7015 STV2246 for Pal sets STV2248 for Pal Secam sets including IF detection video processing chroma decoder RGB sync processor and sound decoder The ICs STV2246 and STV2248 are fully controlled by 2 bus and their block diagram can see in fig 7 1 7 1 1 IF detection IF detection can be intercarrier no multistandard sets that means sound and picture are detected in the same circuit PIF or QSS Quasi Split Sound used in multistan
20. 2s so wewews DAG POS PARTNUMBER DESCRIPTION ESPEC A 5040 313012050140 no ans aseo B 5441 311233830882 une priver arous IA B 5445 313010831050 wouwETRAroioriecrs 14717 B 5225 1 10830992 Live aro Lor 2021 poor B 5480 312813831292 17202 D 5500 312233831732 _ wansruter 029 D 5500 311110835001 henr LAN D 5525 313010831030 sors traro 20 2 2027 D 8525 313010831060 sopstransr tamm A 3502 NEW COMPONENTS RESPECT CTN BB CHASSIS 23 11 2 Electromechanical CTS AA CHASIS TABLE 11 CATHODE PICTURE TUBE CPT um AND ASSOCIATED COMPONENTS ASACRT 14 823009009280 8N2 470N 1015 48 EJNO2X 20 PHILIPS 9301 823 10361 330N A51EAL155X 21 PHILIPS 8230 090 09290 9N1 470N 8N2 470N 2R ABTEER131X78 21 SAMSUNG 313010060621 9N1 330N 2R 106 5 1R A51EER131X81 21 SAMSUNG 8230 210 64050 9N1 A51EFS83X191 21 THOMSON 8230 090 09450 8N2 DESCRIPTION CODE SAFETY DEGAUSSING COIL 14 3130 108 21271 DEGAUSSING COIL 20 21 3130 108 21262 LOUDSPEAKER 14 25 OHMS 3130 100 60191 3130 100 20401 4 LOUDSPEAKER 16 OHMS TV 20 21 4 LOUDSPEAKER 8 OHMS TV 20 21 3130 100 60301 REMOTE CONTROL MENU TXT 3130 108 21341 DEAE REMOTE CONTROL MENU
21. 6521 and used to supply the IC on pin 6 Soft start pin 7 The capacitor C2523 causes a slow increase of the duration of the output pulse during start up C output pin 5 This output drives T7525 R3523 is a fuse resistor to protect IC from short circuits in T7525 D6516 limits the maximum voltage in T7525 Start conduction of T7525 pin 8 A voltage proceeding from winding 4 2 is applied to this pin The zero crossing detector recognizes the complete discharge of the energy stored in the transformer core in addition to a dead time depending on C2508 This circuit guarantee that T7525 starts conduction at minimum Vds voltage see fig 7 5 Primary current info pin 2 Current primary winding is simulated by a pin 2 voltage Output voltage info pin 1 The voltage across winding 4 2 is rectified by diode D6515 divided by R3517 R3518 and R3508 and applied to pin 1 Internal control voltage Vcont inversely proportional to Vpin1 is generated Output regulation pins 1 2 8 107514 stabilizes output voltage by controlling T on and so the frequency and the duty cycle Start pulse to T7525 is determined by pin 8 circuit see fig 7 5 Then a sawtooth voltage V2 is generated at pin 2 Stop pulse to T7525 is produced when V2 reaches Vcont Output control is done by the following way If output is higher V1 is higher Vcont is lower T on and output will be reduced If output is lower output will be increased Output voltage of supp
22. AFC LP Ag 00 _ 7 8 0 Table 8 1 Service menu Settings hexadecimal values Pre setting values When E2PROM is replaced pre setting values indicated on table 8 1 are stored by the uC see 8 7 E2PROM Adjust by Service Mode When a item is selected using V V keys of remote control it can be adjusted Items 5 16 and 17 have fixed values pre setting values rest of items see 8 2 to 8 7 Remove service menu There are 2 ways to remove service menu Saving the new settings Using OSD MENU or INSTALL keys on RC Keeping the old settings Switching the TV to stand by Service mode continues active Remove Service Mode Switching off the TV be careful to disconnect pin 7 of microcontroller of ground 8 2 Power supply and focusing Power supply voltage Adjust brightness and contrast controls at minimum Connect a DC voltmeter across C2530 Diagram D Adjust R3518 for a required voltage depending on the model and the TRC used see table 11 page 23 Focusing Adjust with the potentiometer placed on the line output transformer 18 8 3 AFC IF Carrier frequency can be adjusted in automatic or manual way It is recommended the automatic way There is an adjusting symbol for AFC on the top of the service menu consisting of a double arrow gt lt If only one arrow appears lt or gt AFC should be readjusted to reach double arrow gt lt 8 3 1 Automatic AFC adjustment Inser
23. C 20us div TP39 D 5v DC TP39 D 0V DC TP40 D 25V DC 0 OV DC 41 0 5v6 DC TP41 5 6 DC 5 PRINT BOARD LAYOUT E m SEN R 3 CU 1 4 mo re gt eat META iz WLS Va 7277 pae 7 it S 113118 ss gt fa lt x H UE E N I P s XD ay e ms cx 19 NS OBRA GS ii 4 NS em E oe 3 f ray irrt 222 2 Tn 2 7 4 EA k l jen z 9 y Sy gU Be Nee SAE Se ae P oo Uls she QE aie SRR UL sistas Ee Ra pers E TU i a z SN CI S T m 5 Nad _ t S SUSU Sts fan CAS 5783 NIJ t 7 3 pat io X 4 E 1 P MAG 7 9190 ES A Ad Te GN p m or Roa y av jov SOLL VAL p m oe COT OLTE 6 Electric Diagram 3281 F3 1015 D6 CN CO co XN XN c oo OO OO DAR KR AD oo 00 CO co co I ON c OO CO cq CY 1
24. I t 10 10 CO KR OO o o 1 co d CO CO 1 0 Oroonoreordwuor QN CO st WO O O dO o OIL OIL OIL OIL ON OI QN CO CO CO CO CO CO 3606 C6 3607 C6 3608 E7 3609 F7 3610 C7 3611 C8 3612 C8 3616 D2 3617 E2 3618 F7 3619 G7 3620 F6 3621 D7 3636 L7 3637 K7 3643 3644 J3 3645 J3 3646 J3 3647 3648 L7 3649 J3 3650 J4 3651 J4 3652 13 3653 4 3656 3657 3658 3659 E3 3660 F2 3661 17 3662 F3 3663 J7 3664 J8 3665 G8 3666 J7 3667 G8 3668 12 3669 12 3670 I3 3673 18 3674 J8 2292 dq m 3 Jj 4 Tq uw y 0892 9 96 8155 81565 47828 69 NER GENE CENE IDEE gt 33417114 ONAS ON LSEAO AS8GNVIS 0S8AO VSSA 10S c Vas Wd ONASH 1 98 ONASA dSSA IdHA QN9QSO NIIVLX ON LNOWLX ON 1393 QHVO8A3 SVO MS LX3 LNI JOIAMH3S 0097 9c 9 c 1 MVC 8795 NOOL 5 96 c 8795 gs NOOL 7196 9595 CAZ 1 1 SSAO 9595
25. NO TXT 3130 108 21351 REMOTE CONTROL BARS NO TXT 3130 108 21361 REMOTE CONTROL BARS TXT 3130 108 21371 6 LOOP AERIAL 3130 100 20482 7 ROOD AERIAL ONLY FOR EIRE 3130 100 20361 11 3 Mechanical chasis and switches CTS AA CHASIS DESCRIPTION SECURITY MAINS KNOB SENSOR COVER A AN 71 wmomess NS POSITION SCREEN TVMODEL COLOUR HOW TO ORDER EXAMPLE FRONT CABINET OF TV700TX COLOUR BLUE 14 TV700TX AZ 24 NG BLACK BL WHITE GR GREY MA IVORY GO DARK GREY VE GREEN RS PINK RJ RED AZ BLUE PL SILVER
26. SERVICE MANUAL CHASSIS CIS AA CONTENTS 1 Technical specifications 2 Connection Facilities 3 Mechanical instructions 4 Oscillograms 5 Print board layout 6 Electric Scheme 7 Circuit description 7 1 Small signal processing 7 2 RGB ampliers 7 3 Deflection 7 4 Sound amplifier 7 5 Power supply 7 6 Microcontroller Text 8 Electrical adjustments 9 Safety instructions 10 List of abbreviations 11 Service components 1 Technical specifications CHASSIS CTS AA Mains voltage 220 240 V 10 AC 50 Hz 5 Power cons at 220V 35W 14 50W 20 21 SW stand by Aerial input impedance 75S coax Min aerial input VHF 30uV Min aerial input UHF 40 Max aerial input VHF UHF 180mV Pull in range colour sync 300Hz Pull in range horizontal sync 600 Hz 480 Hz Pull in range vertical sync 5 Hz Picture tube range 14 20 21 ii Mono 255 1W 14 165 2W 20 21 TV Systems PAL BG PAL I PAL BG SECAM BGDK PAL BGI SECAM BGLL Indications On screen display OSD menu 1 LED RED Dark in ON bright in stand by blinking with RC VCR programs 0 to 99 Tuning and operating system LLL VST UV1315A IEC VST VHFa 48 168 MHz VHFb 175 447 MHz UHF 455 855 MHz U1343A IEC VST UHF 471 855 MHz Local operating functions Vol Prog contrast colour and brightness SK1 P RED 5 5 MENU 2 Connection facilities
27. V and program 99 constant is always fast to prevent top bending on the screen LBF pin 49 Line Fly Back input is obtained by the network R3456 55 Diagram B T7372 and R3371 Output of T7372 is used also as HSYNC of the uC pin 36 IC7600 diagram D When the DC voltage of pin 49 is higher than 2 5V HOUT pin 48 is inhibited protection SSC output pin 49 Super Sand Castle output is used only internally Levels of sandcastle pulse are 5V for burst detection 3V for line blanking and 2V for frame blanking Horizontal 2nd loop circuit The flyback position respect line blanking on TRC cathode is controlled in this circuit Phase can be adjusted by 2 HOUT pin 48 Horizontal output is an open collector which one drives the horizontal driver stage 17440 diagram B 7 1 7 Vertical synchro Vert sync separator It is an internal integrator to separate frame sync pulses from CVBS Vertical oscillator Vertical frequency is obtained internally from line frequency by a line counter Mode used Is automatic 50 60Hz identification with 50Hz priority Vert output stage pin 43 This pulse output is used to drive the sawtooth generator in the vertical amplifier pin 3 1 7400 diagram B and also as VSYNC of the uC pin 37 IC 7600 diagram D The VERT pulse period is 314 lines 50Hz free running mode 264 in 60Hz and 312 5 lines in 50Hz synchronized mode 262 5 60Hz Frame blanking is from line 2 to 12 5 Vert a
28. again with the setting values of table 8 1 items 9 10 13 14 15 8 6 Geometry Connect a circle pattern generator with the controls at nominal conditions and enter to service menu Horizontal shift Adjust to have picture centred in horizontal position by service menu item 18 Vertical amplitude Adjust picture height to cover the screen by service menu item 19 Vertical centring Occasionally it is possible to correct the vertical centring cutting resistors R3400 R3401 TXT Shift Horizontal shift of OSD or TXT can be adjusted by item 20 of service menu 8 7 Options The type of chassis is defined by items 21 and 22 of service menu The following alternatives are available T3 Languages menu o Engish bars menu o menu without languages 03 Only 13 languages menu 04 07 m mse o 1 PALSECMWBIG DK 03 L 04 05 PAL SECAM B G L LP 04 PAL SECAMBB G I L LP Only UHF global menu without languages PAL SECAMB G 1 DK L tP E E Important note All the chassis have identification sheet when the chassis type is indicated Cod service SXXMXX where SXX means the option of system and MXX means the option of menu Only UHF English bars menu Example 503 00 means system 03 Pal Secam B G DK and menu 00 13 Languages menu When the chassis or the EEPROM 1C7685 have to be replaced be careful to keep the same type o
29. age Synthesized Tuning Luminance part of video signal 22 11 REPLACEMENT PARTS LIST 11 1 Electrical MISCELANEOUS DAG POS PARTNUMBER DEsCRPTON esec B 23 313010060681 mmni crs ZN 23 313010010131 20 21 narrow 2027 A B 160 312807801731 pe B 160 313010867600 entcasezr frat 1001 313914712881 runer uisasasn Jue f A 1015 313010080520 saw ruter kassu ___ f 1015 242254941518 saw Fuerer 1016 242254941482 saw Fiter ow PALL 1015 932204272682 saw ruter KSOSSM 1032 242254940095 cen mapssmiz BGK 1033 242254903572 TRAPGOMHZ feai f 1093 242254903595 cer rapes mz A 137 313010080490 saw eo mun 1272 313010080500 wz f D 1500 242208610536 ruscristzazsovexo 1540 313010080072 Fusuc 4 D 1540 313010080510 rusiacizea frat 1541 242208610417 frusiacesoma J IA 1679 313010080076 oer cristar 2m E 1685 313010070024 tso ses DIAG POS PARTNUMBER DESCRIPTON Esec 2445 202055890333 caeceRPLzme xv See table 11 N _ 2445 202055890335 cere v See table 11 A B 2446 222237682912 on1 See table 11 A 2446 222237682822 enz 1
30. al is made by 06573 17577 circuit R3577 is connected to 8V to switch off 5V when the set is in stand by mode 5V stand by 5STB is regulated by T7575 and D6570 A positive power on reset signal POR is obtained in the collector of T7571 which one is cut during start up till R3576 has 0 6V 8 md Start V pin 2 St Foldbank lt Stop Vpin5 VGs ANNE t DS 1 1 Foldbank ae LI a 2 97 point I 1 V DS T dead Ton T off Figure 7 5 Power supply signals 7 6 MICROCONTROLLER TEXT Diagram E The CTS AA chassis is designed to accept 2 different microcontrollers SAA5531 for TXT models and SAA5541 for no TXT Both microcontrollers are mounted in the same position 7600 and the associated circuitry is the same The ROM of the ICs contain an specific program that assures all the functions of the appliance including 2 menus one to control the set see Instructions Manual and another for Service Mode see Service Instruct chapter 8 1 The uC for TXT sets contains a teletext decoder including the following functions TXT on off reveal freeze temporary cancellation clock subcode zoom index page X 26 and 8 30 packet decoding station identification and start up page Following there is an explanation of the different functions of the microcontroller indicating pins number assigned Tuning pins 1 9 The unit has a VST Voltage
31. and so BCI decreases for increasing beam current diagram C and the picture will be corrected Switching signal from uC low for or DK reception 6 0 or 6 5 MHZ FM sound high for BG reception 5 5 MHZ FM sound Sond system BG I DK LL indicate frecuency distance between sound and picture carriers 5 5 MHz for 6 5 MHz for DK and LL Switching signal from uC low for BGIDK reception negative modulation FM sound high for LL reception positive modulation AM sound Brightness control signal same as BRIGHTNESS Control signal from uC but on DC level via RC network for brightness control of the video controller IC7015 6D Bandswitcing signal from uC to 2 to 3 decorer 7002 Bandswitching signal from uC to 2 to decorer IC 7002 Control signal from uC but on DC level RC network for brightness control of the video controller 1C7015 6D Picture tube Colour Video Blanking Synchronisation from pin 7 IF detector 1C7015 6A Direct current Electrical Eresable Programmable Read Only Memory Extra High Tension 25 KV Field Effect Transistor Filatement heather voltage Frecuency MOdulation Horizontal flyback pulse 15625 Hz used for locking the horizontal oscillator in 7015 6 and for locking the OSD generator in the uC Horizontal drive signal from 1C7015 6E to line output stage Tint ajustment for NTSC system Digital Control bus of the microcomputer Status signal low for horizontal synchronisation high
32. back time This is produced adding the flyback signal present at pin 10 to a 25V supply by D6401 and C2410 Vertical driver 3 A vertical pulse is drived by pin 47 of I1C7015 This pulse is used to synchronize vertical oscillator Vertical oscillator pin 6 Saw tooth is performed in the capacitor 2406 R3417 makes a feed back to stabilize vertical amplitude from beam current Vertical amplitude pin 4 A DC voltage originated at pin 42 of IC7015 and adjusted I2C bus is applied to pin 4 to modify vertical amplitude Vertical output pin 1 Vertical output is applied to deflection coil DC current is suppressed by C2404 A voltage proportional to current deflection is present in R3411 12 and a feedback of it is sent to pin 8 across C2405 R3405 and R3407 A DC feedback is obtained by resistor divider R3403 and R3404 Linearity is corrected by the network C2405 and R3405 CRT protection 7430 7431 When frame deflection is broken down transistor 7430 is cut and 7431 conducts so that the signal BCI SAF OV and the line is switched off protecting the tube see pin 46 of IC7015 7 3 2 Line deflection The final line transistor is driven by the transformer 5441 whose primary winding is driven by the transistor T7440 connected to the line drive output of 1C7015 pin 48 The horizontal deflection stage is carried out in a conventional way with the deflection transistor T7445 and line transformer 5445 Beam current info BCI
33. dard sets where sound is detected in a separated circuit SIF PIF input pins 6 7 The IF signal coming from pin 11 of the tuner diagram C is filtered by the IF SAW filter 1015 and applied to PIF input of 1C7015 pins 6 and 7 The IF bandpass characteristic is determined by the SAW Surface Acoustic Wave filter PIF oscillator pins 9 15 16 The PIF PLL phase locked loop is based on aLC resonator L5040 Carrier frequency should be adjusted by I2C bus at 38 9 MHz see chap 8 3 A filter for the PLL is present at pin 9 2028 2029 3028 AFC is internally controlled for the uC 7600 diagram E by 12C Identification signal is also internal AGC pins 5 8 The IF AGC time constant 1 fixed by the capacitor 2025 pin 5 The AGC delayed voltage pin 8 is applied to pin 1 of the tuner and adjusted by 2 see chap 8 4 Video output pin 13 This baseband CVBS signal with 2Vpp of nominal amplitude contains the FM intercarrier sound signal Sound is filtered out by a ceramic trap 1032 or 1033 which frequency can be different depending on the system 5 5 MHz for BG 6 0 MHz for or 6 5 MHz for DK Multistandard sets The IC STV2248 is used in multistandard sets Only picture IF is processed in PIF circuit pins 6 7 and carrier frequency has a second adjustment by 2 at 33 9MHz for L standard see chap 8 3 The changes automatically between negative BGIDK and positive LL modulation Sound IF
34. econdary side is checked This check can be done as follows Unplug the mains cord and connect a wire tween the two pins of the mains plug Switch on the TV with the main switch Measure the resistance value between the pins of the mains plug and the metal shielding of the tuner or the aerial connection on the set The reading should be between 4 5 M and 12 M Switch off the TV and remove the wire between the two pins of the mains plug Thermally loaded solder joints should be oldered This includes components like LOT the line utput transistor fly back capacitor Maintenance Instructions It is recommended to have a maintenance inspection carried out periodically by a qualified service employee The interval depends on the usage conditions When the set is used in a living room the recommended interval is 3 to 5 years When the set is used in the kitchen or garage this interval is 1 year During the maintenance inspection the above mentioned safety instructions for repair should be caried out The power supply and deflection circuitry on the chassis the CRT panel and the neck of the CRT should be cleaned 21 1 In order to prevent damage to IC s and transistors any flash over of the EHT should be avoided To prevent damage to the picture tube the method indicated in Fig 9 has to be applied to discharge the picture tube Make use of an EHT probe and a universal meter is OV after approx 30s 2 ESD All IC
35. f chassis setting correctly the chassis options 8 8 Error messages The microcomputer also detects errors in circuits connected to the 12 Inter IC bus These error messages are communicated via OSD On Screen Display Error message Error description Component F2 Eprom communication error IC7685 F3 uC internal error IC7600 F4 SDA2 SCL2 bus communication IC7015 tracks PCB E F6 Eprom data error IC7685 20 9 Safety instructions maintenance instructions warning and notes Safety Instructions for Repairs Warnings 1 Safety regulations require that during a repair The set should be connected to the mains via an isolating transformer Safety components indicated by the symbol AN should be replaced by components identical to the original ones When replacing the CRT safety goggles must be worn 2 Safety regulations require also that after a repair The set should be returned in its original condition The cabinet should be checked for defects to avoid touching by the customer of inner parts The insulation of the mains lead should be checked for external damage The mains lead strain relief should be checked onits function The cableform and EHT cable are routed correctly and fixed with the mounted cable clamps in order to avoid touching of the CRT hot components or heat sinks The electrical resistance between mains plug and the s
36. following information are stored in the memory Channel data including tuning voltage and band of all the channels Personal preferences PP menu mix and child lock on user menu All settings included on Service Menu 8 ELECTRICAL ADJUSTMENTS 8 1 Service mode The signal processor IC7015 STV2246 or STV2248 is fully controlled by 12C for the uC IC 7600 so that the most of adjustments of the set can be made by service menu Enter in Service mode There are 2 ways to enter in Service mode By a short circuit between pin 7 of microcontroller 7600 and ground while the set is starting up In this case all controls volume contrast brightness and saturation are pre adjusted to the mid position When the set is in program 75 by pressing at the same time OSD key on RC and MENU key on local key board during 4 seconds Service mode is indicated by a S symbol on the down left corner of the screen Display Service Menu When the set is in service mode it is possible to display Service Menu by OSD key on RC Using P P keys of remote control the different items can be displayed see table 8 1 Item Description Pre Item Description Pre E Setting Adjust Setting Adjust 3 AFC Fine B 2E AFC Coarse LP 33 AFC Fine LP 1 1 EN Beier 9 APR Thresh 08 ot 1 1 HOR Shift 2 19 VER AMP 1 22 Menu Options 09 23 jarcadus 00 24
37. g stand by OSD outputs pins 32 33 34 35 The RGB and fast blanking outputs used for On Screen Display OSD and also for TXT are applied to RGB inputs of IC7015 pins 34 35 36 37 diagram A OSD synchronization pins 36 37 In order to synchronize the OSD and the TXT information with the picture signal the VERT FLYBACK signal pin 37 and HOR FLYBACK signal pin 36 are added in inverted form to the integrated circuit Due to this if the video signal is lost the TXT keeps synchronism Oscillator pins 41 42 A 12 MHz oscillator is determined by a 12 MHz crystal 1679 between pins 41 and 42 P O R pin 43 Power on reset POR is activated when the set is switched on If the uC shows abnormal behaviour it is advisable to reset it switching off on the set Reset can be produced also connecting pin 43 to 5V for an instant RC5 pin 45 The commands transmitted by the remote control handset are received by infrared receiver 1685 and passed to the microcontroller for decoding Mute output pin 46 This pin is a 3 state output used to control the sound amplifier see chapter 7 4 Stand by mode Vpin46 0V T7657 and T7659 are cut mute signal is 11V Mute mode pin46 open T7659 conducts by resistor divider T7657 are cut mute is 5 5V Operating mode Vpin46 3V3 Both transistors conduct mute signal is OV EEPROM pins 49 and 50 The microcontroller is connected to non volatile memory 7685 EEPROM via bus I2C The
38. gnal of 33 9MHz instead of 38 9MHz and using AFC coarse LP item 3 of Service menu and AFC fine LP item 4 of Service menu 8 4 AGC Adjustment Connect a pattern generator to the aerial input with RF signal amplitude 1mV Adjust the value of AGC start item 6 of Service menu so that voltage at pin 1 of the Tuner 1001 is 3 7V 8 5 White D 8 5 1 Manual cut off Item 8 of adjusting values should be 00 see table 8 1 that means set is in automatic cut off However it is possible that RGB do not start black picture due to grid 2 is not adjusted In this case we recommend to change to Manual cut off Item 8 01 pre adjust grid 2 to have a good picture and change to automatic cut off Item 8 0 before continue adjusting see warm up detection circuit in 7 1 5 8 5 2 Grid 2 Connect a white pattern generator Adjust contrast at 07 and brightness at 22 Adjust VG2 potentiometer in line transformer till voltage in collector of transistor 7213 is 142V in 20 21 or 134V in 14 measured with a DC voltmeter 19 8 5 3 White checking Connect pattern generator containing grey scale Adjust the set to normal operation and reduce the saturation control to minimum Allow the set to warm up about 10 minutes and check visually if the grey scale has correct colour If not enter to Service menu and adjust G and B gain items 14 and 15 until a desired grey is obtained In the case that adjusting is difficult start
39. in case horizantal synchronisation is detected Intermediate Frecuency Switching signal derived frompupP INT EXT and 8 of SCART to pin 16 1C7015 6B and IC7140 diagram D low for internal high for external Switching signal from uC low for BGIDKL picture at 38 9 MHz reception high for L reception picture at 33 4 MHz Light Emitting Diode Line Output Transformer Only for sets whithout SCART AV low for program 0 muting the sound high for program 1 39 Non InterLace National Television System Committee On Screen Display Fast blanking info from OSD generator in uC to video controller IC7015 6D for blanking the RGB info to enable OSD G insertion Green info from OSD generator in uC to video controller 177015 for inserting green OSD info on screen Phase Alternating Lines Phase Locked Loop Power On Reset ensures the uC starts up it s software only if the power supply of the uC itself is high enough Switching signal from IC7140 via BG L high for positive modulation LL highihmic for negative modulation BGIDK Personal Preference Prottection signal from frame IC7400 case vertical flyback generator in 1C7400 is not activted the voltage at pin 8 7400 becomes 2V Protection circuit in 7400 will make pin 7 high overrulling the FLYBACK and SANDCASTLE The constant high sandcastle is supplied to the luminance circuit and so the picture will be blanked Positive Temperature Coefficient Resistor
40. ly can be adjusted by R3518 Mains voltage variation is stabilized in the following way If mains voltage is higher slope in the sawtooth voltage V2 is higher stop point is reached before and T on is reduced If mains voltage is lower T on is increased 7 5 3 Protections Overload protection pin 2 This is produced if T on is increased till V2 voltage reaches the foldback point see fig 7 5 The IC will switch into overload mode off and on continuously Output voltage protections pin 6 Limiting values of V6 voltage 7 25V and 16V provide under and overvoltage protections for the circuit Mains overvoltage pin 3 The voltage at pin 3177515 is a measure for the mains voltage and so the DC voltage across C2505 As soon as the voltage V3 reaches 6 6V the supply will stop running 7 5 4 Secondary side Line supply Line supply present at capacitor C2530 should be adjusted to the correct value depending on the TRC by means of P3518 This supply is also used to obtain 33V varicap voltage by 06602 see diagram Sound supply 11V This supply is used for sound output amplifier and to feed following stabilizers 8V stabilizer A reference voltage obtained by a resistor divider R3503 and R3505 is amplified in T7501 and T7502 transistors till diode 06572 conducts stabilizing 8V output When the set switch to stand by standby voltage is OV then T7501 is cut and 8V is reduced to OV 5V stabilizer 5V for small sign
41. mplitude pin 42 This DC output is applied by a divider resistor R3416 R3414 diagram B to pin 4 of IC7400 to control vertical amplitude It can be adjusted by I2C from 1 5V max vert amplitude to 6V min vert amplitude 7 2 RGB AMPLIFIERS diagram B RGB inputs The inputs of RGB amplifiers come from pins 32 31 and 30 of IC7015 Diagram A White D is adjusted in IC7015 changing the AC level of the inputs by 2 bus and cut off changing the DC level RGB amplifiers 7205 7210 7213 RGB circuit consist of 3 inverter amplifiers 7205 7210 7213 including active load 7201 7208 7211 To improve high frequency amplification there are small capacitors 2204 2217 and 2230 and to adapt DC level for inputs there is a diode 6225 Cut off control 7204 7209 7212 Cathode current produced at cut off pulses is applied to cut off control circuit pin 33 of IC7015 see 5 1 5 across transistors 7204 7209 7212 Diode 6243 is added to prevent high voltage 7015 Flash over protections Clamping diodes to 200V 6201 6218 6227 and 1K5 series resistors 3203 3216 3326 3228 3229 are added for protect the circuit from TRC flash over 7 3 DEFLECTION Diagram B 7 3 1 Frame deflection This function is performed by the integrated circuit TDA1771 7401 Frame supply pins 2 9 10 Pin 9 is used to supply the IC except output stage which one is supplied by pin 2 At pin 2 there is a higher voltage during fly
42. n such a way that when headphones are connected loudspeakers are switched off 7 5 POWER SUPPLY Diagram D Mains isolated switched mode power supply SMPS controlled by 177514 TDA4605 in variable frequency mode Switching behaviour The switching period is divided in on time when energy is extracted from the mains into the primary winding 8 12 of 5525 off time when energy in the transformer is supplied to the loads via secondary windings of 5525 and dead time when no energy is extracted or supplied Standby mode Output voltages are present when the set is on stand by due to standby is done cutting line deflection On time is lower and power consumption is very low 7 5 1 Primary side Degaussing R3501 is a dual PTC 2 PTC s in one housing After switch on set PTC is cold so low ohmic and so degaussing current is very high After degaussing PTC is heated so high ohmic so in normal operation degaussing current is very low Rectifier Mains voltage is filtered by L5500 full wave rectified by diodes D6502 D6505 and smoothed by C2505 300V DC for 220V AC mains 7 5 2 Control circuit 167514 Start up and supply pin 6 When the set is switched on a current via R3507 is applied to pin 6 When C2514 is charged to 15V the power supply starts and a current from pin 5 to T7525 is drived T7525 and starts conduction and a voltage across transformer windings is built up The voltage across winding 4 2 is rectified by diode D
43. r switching YUV signals are converted to RGB in the internal MATRIX circuit Saturation control is received from the uC by I2C bus APR pin 24 The APR circuit Automatic RGB Peak Regulation compensates the spread of contrast between sources If one of RGB signals exceeds the APR threshold 2440 is charged and the gain is decreased APR threshold can be adjusted in Service menu RGB OSD pins 36 35 34 RGB inputs for OSD and TXT coming from uC 7600 diagram E are AC coupled C2242 43 44 and applied to a RGB SWITCH controlled for the uC by fast blanking input pin 37 Video controls Contrast brightness and saturation are adjusted by 12C for the uC BCL input pin 46 Beam current is limited by circuit BCL SAF When beam current is high voltage of C2460 is lower Diagram B D6462 conducts and Vpin46 is lower When Vpin46 5 75V first contrast and then brightness are reduced Safety input pin 46 BCL SAF circuit has also a safety function If frame deflection is broken down T7431 conducts Diagram B Vpin46 OV and line deflexion pin 48 is disabled RGB output circuit pins 32 31 30 RGB outputs are drived to RGB amplifier Diagram B Digital cut off loop pin 33 Cut off loop permits to control automatically the cut off point of the 3 RGB cathodes by DC level At the end of the frame blanking 3 consecutive cut off lines B G and R are created Cut off current flows across T7204 T7209 and T7212 Diagram B respec
44. t a 38 9MHz 106dB uV signal in pin11 of the tuner 1001 diagram C across the following network gt 115 Ohm 4 5 F P100 GEN 50 Ohm Note For Pal sets frequency is 38 9MHz only if saw filter 1015 diagram A used is J1952 If saw filter is J1951 frequency of the inserted signal should be 39 5MHz Select AFC Adjust item 23 of Service menu and press V on RC Press OSD key to save adjustment Enter in Service menu again and check that adjusting symbol is correct gt lt If not readjust AFC Fine item 2 of Service menu till symbol is gt lt Multistandard sets A second adjustment for L system is necessary when the set is multistandard to do it TV should be tuned in the first half of BI L channel Repeat the same automatic AFC adjustment procedure inserting a signal of 33 9MHz instead of 38 9MHz and using AFC LP Adj item 24 of Service menu and AFC Fine LP item 4 of Service menu 8 3 2 Manual AFC adjustment Insert the frequency signal defined in 8 3 1 Adjust the value of AFC coarse item 1 of Service menu to 00 and the item value of AFC fine item of Service menu to 40 Increase the AFC coarse value just till adjusting symbol is gt lt or and adjust AFC Fine to fine a value just in the middle of the range fulfilling the correct symbol gt lt Multistandard sets TV should be tuned in the first half of BI L channel Repeat the AFC Manual AFC adjustment procedure inserting a si
45. tching 15 for VHFI pin 16 for and pin 14 for UHF The controls the channel band in the tuner by a voltage of 5V at the correspondent output L L out put pin 18 This signal are only used on multistandard units for switching the system in sound filter see 5 1 5 L L output is high for L system LED pin 19 The LED D6663 lights up with a low current when the television set is ON and with a high current when the set is on Standby While the set is receiving a remote control signal the led is blinking Signal 2 bus pins 20 21 This is a communication bus between the uc and the signal IC 7015 Picture and sound controls User controls brightness contrast colour sharpness and volume are processed by the uc and sent to 7015 by 2 bus The uc also sends a sound mute when the signal received is interrupted including channel search and a video mute during a change of program Video input pin 23 CVBS TXT input are only used on TXT sets The teletext information is extracted from the video signal inserted on pins 23 Standby pin 30 When this output is low the set is switched to stand by Signal voltages of power supply 45V 8V diagram D are reduced and the line oscillator stops so there is no signal in pin 48 of IC7015 diagram A Power supply pins 31 39 44 The IC has several 3V3 power supplies analog pin 31 core pin 39 and POR periphery pin 44 All supplies are present durin
46. tively and it is measured on pin 33 When VG2 voltage is adjusted DC level of RGB outputs is adapted to keep cut of current Warm up detection circuit pin 33 At the start up picture is blanked and 3 white lines are drived instead of cut off lines As soon as the start beam current is detected on pin 33 RGB circuit starts in normal operation If RGB circuit is damaged or grid 2 is low the RGB circuit could not start black picture due to current is not detected 7 1 6 Horizontal synchro Start up pins 45 53 The horizontal oscillator starts running when supply voltage of pin 45 reaches 6V and supply voltage of pin 53 reaches 4V During start up circuit provides a softer operating horizontal output with a 7596 of duty cycle 13 Note The set do not start up if protection voltages are activated Vpin 49 gt 2 5V or Vpin46 lt 1V Hor sync separator Fully integrated sync separator with a low pass filter slicing level at 50 of the synchronized pulse amplitude Horizontal 1st loop circuit pin 50 The first phase locked loop PLL1 locks the internal line frequency reference on the CVBS input signal It is composed of an internal VCO 12MHz that requires the chroma reference frequency 4 43MHz at pin 40 a divider by 768 a line decoder and a phase comparator Scanning PLL1 filter SLPF needs external components on pin 50 PLL1 time constant is automatically controlled by software for broadcasting signals For video signals A
47. ts but the input proceeds of SIF circuit instead of CVBS signal AM demodulation In Multistandard sets also AM demodulation for LL systems is necessary AM sound is extracted directly from the SIF inputs by an internal circuit AM FM switch This internal switch is commanded by the uC depending on the system selected on the tuning menu 7 1 3 Video processing Video switches pins 18 20 44 The internal CVBS signal is now fed to 18 7015 External CVBS proceeding from pin 20 of Euroconnector is present pin 20 of 7015 The IC switches between internal and external by 2 bus see INT EXT chapter 7 6 At pin 44 there is an output of CVBS used for the TXT decoder 12 Luminance processor CVBS coming from video switches Is internally applied to luminance processor which is composed of chrominance trap filter luminance delay line and peaking circuits Sharpness control modifies peaking by 2 Black stretch circuit pin 21 This feature of the picture is fixed not adjustable Black stretch capacitor 2250 is connected to pin 21 7 1 4 Chroma Decoding ACC and chroma filter Video signal coming from video switches goes through an internal variable gain amplifier to the chroma band pass filter Gain of amplifier is determined by burst amplitude ACC If the amplitude of chroma signal is higher than standard an additional overload circuit decreases it ACCO XTAL pin 40 The VCO uses one 4 43MHz crystal
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