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Download CHASSIS CTU-AA SERVICE MANUAL - Page de test
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SERVICE MANUAL CHASSIS CTU-AA 1. Technical specifications CHASSIS CTU - AA Mains voltage Power cons. at 220V~ Aerial input impedance Min. aerial input VHF Min. aerial input UHF Max. aerial input VHF/UHF Pull-in range colour sync. Pull-in range horizontal sync. Pull-in range vertical sync. Picture tube range : 220 - 240 V ± 10% AC; 50 Hz (±5%) : 35 W (14’’), 50W (20’’/21’’), 3W (Stand-By) : 75 Ω - coax : 30µV : 40µV : 180mV : ± 300Hz : ± 600 Hz : ± 5 Hz : 14'' / 20’’ / 21‘’ : Mono: 25∧ 1W (14’’), 16∧ 2W (20’’/21’’) : Stereo : 2x16∧ 2x4W (21’’)+ TV Systems : : : : PAL BG PAL I PAL BG / SECAM BG DK PAL BG I / SECAM BG L L' Indications : On screen display (OSD) green and menu : 1 LED (red in ON and blinking red in stand-by) VCR programs : 99 Tuning and operating system : UV1315A / IEC (VST) : VHFa: 48 - 168 MHz : VHFb: 175 - 447 MHz : UHF: 455 - 855 MHz U1343A / IEC (VST) : UHF: 455 - 855 MHz Local operating functions : Vol/Prog, +, -, contrast, colour, brightness and sharpness (and hue on program AV with NTSC signal). VST 2. Connection facilities Euroconector: 1 2 3 4 5 6 7 8 9 10 - Audio Audio Audio Audio Blue Audio Blue CVBS status 1 Green 11 - Green 12 13 14 15 - Red Red 16 - RGB status R (0V5 RMS ó 1K ). R (0V2 - 2V RMS ò 10K ). L ( 0V5 RMS ó 1K ). 17 18 19 20 21 - CVBS CVBS CVBS CVBS ( 1Vpp 75W ). ( 1Vpp/75W ). Earthscreen. L (0V2 - 2V RMS ò 10K ). (0V7pp/75W ). (0-2V int., 10-12V ext.). (0V7pp/75W ). Head phone: (0V7pp/75W ). 8 to 600Ω. Mono : 25mW at 32Ω (0-V4 int.) (1-3V ext. 75W ). Stereo : 2x 6mW at 32Ω. 3,5mm ø. 3 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 Fig. 3.2 4 4. Oscillograms 5 5. Print Board Layout UHF +8 3004 2K7 +8 3006 2K7 SC_AUDIOOUT V_VARI 9103 A1 2092 RES 3010 * 3007* 100R * 3026* 100R 2091 RES 3 3003* 100R 2090 RES 3002 2K7 VHFI C11 A1 A7 13V 15K 2610 220N 3610 * 2602 10U * 4 +5A 9496 2K7 9416 2001 100U 7104 * BC847 +8 3008 4K7 5K6 3104 * 3103 1K2 2006 22N 1 6 2416 100N 2 2412 2N2 2411 2N2 2417 TP11 100N +12B 9414 +45 9664 9665 7605 * PMBT2369 3410 * 3613 47K 3614 47K 270R 3663 150 3605 220K 3412 2K 1% 5 * 3604 * 3603 24K 3411 2K 1% 3416 3415 3615 RES 3675 1K3 6413 * 2403 68N -TUNER - 1001 330K 3413 * VHFIII A5 +8 A8 TP15 3402 390R - FRAME - M5:2 TP16 9417 VGUARD VHFIII UHF VHFI LED VHFIII INT/EXT MUTE 3414 75R 10K 7601 * BC847 3611* 10K 2611 220N 6602 HZT33 * 3602 1K5 3612 KEYBOARD V_VARI M5:1 A9 A5 A8 A7 C6 A5 C4 C3 C2 A1 * * * * 3601 1K5 VHFI 3102 1K2 1 2 3 4 5 6 7 8 9 9016 9017 22K 3607* SCL_2 100R 3407 9435 0R05 3020 6020 RES 2 1 2367 1N2 2308 22N 2307 4N7 2305 2N2 2304 220N 2302 22N 2301 220N +3V3A +3V3A 29 28 27 26 25 24 2104 4N7 3101 2K7 32 31 30 2106 2102 2018 10N 100N 2340 39K 1% 3341 * 5 3015 * 47R 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 3682 5K6 1 +3V3A 4 3014 * 47R 2103 9102 3019 180R 2111 820P 3018 27K 3017 2K2 +5A 3 2366 1N2 1015 9402 9401 2309 2U2 15K 3301 * 2303 100U 5301 10U 22K - IF - 10 11 1K5 TP34 TP33 9682 3618 * 3656 * 2306 1U 3406 100R +5 TP21 STBY +3V3 +8 +8 +8 9434 Vi_A Vi_B Vcc OUT_B GND VFB OUT_A GUARD FBACK 2017 47U +8 SDA_2 7401 TDA8357J +8 +8 TP17 9618 10K 3606 * 9061 * +45 * * VHFIII * * * * * * * * * * * * BO GO RO VSSA SECPLL VP2 NC SNDPLL HOUT FBISO AUDEXT EHT DECSDEM GND2 PLLIF IFVO/SVO VP1 AUDEEM TUNERAGC VSC CVBSINT GND1 IFIN2 IREF CVBS/Y NC IFIN1 VDRA AUDOUT R2/VIN DECBG VDRB G2/YIN GND3 INSSW2 B2/UIN PH1LF AVL/EWD BCL PH2LF CUT_OFF/VGUARD VDDA P0.6 DECDIG VPE P0.5 VDDC OSCGND P3.3 VSSC/P XTAL_IN XTAL_OUT P3.2 P3.1/ADC1 RESET ADC1 INT1 P1.7/SDA VDDP SDA P1.6/SCL TPMW SCL P1.3 7015 3629 1K 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 390R 3023 * 3022 * TP9 9403 27K 3371 TP10 2023 47N 150R TP22 2U2 2105 3372 22K 9404 9371 3025 22K 100N 3027 100K 470R 3373 * 6372 8V2 220K 1033 3028 5032 8U2 3030 1R SIF A16 +8 E17 A16 C18 E19 C19 C20 C21 C22 C23 D24 A9 B24 B25 B26 B27 B28 D29 C30 EHT +3V3 LINE_DRV H_FLYBACK AUDIO_EXT 3033 1K D12 D13 C14 D15 - VIDEO - INT_CVBS 2036 * 100U 180R 7005 BC847 +8 INT_CVBS +8C 9004 5033 10U CVBS_EXT AUDIO_OUT FB_EXT R_EXT G_EXT B_EXT BCL VGUARD CUT_OFF R_OUT G_OUT B_OUT 3031 * 2032 100U TP32 3496 1K M7:5 M7:3 M7:2 M7:1 M7:4 +3V3 +3V3 +3V3 POR RC5 GND_RGB +3V3 9695 9536 9613 RES 9621 4 3 2 1 2600 RES +3V3 +3V3 +3V3 RES 3032 * 1032 100R 3034 * +8A 100N 2010 * 100R 3291 * 100N 2291 * 100N 2292 * 100N 2293 * 3495 10K 2021 * +8C * +8A 2031 100N 7004 BC857 1K 47N 3035 100R 2034 * 2298 100N +3V3 3621 100R 2290 * 470P 5601 10U 1K 6496 * LL4148 100R 3292 * 3293 * 100R 3294 * 100R 3295 * 2612 100N 10U 2601 100U 2604 * 33P 10U 7685 24C04 3628 5 6 7 8 5607 * 5602 2623 100U 2603 * 2613 100N 2299 RES TP30 52 TP29 53 TP28 54 55 56 57 2628 100N 9656 33P 3685 2K2 2622 100N +3V3A 1679 12MHz 58 59 60 61 62 63 3684 2K2 64 +3V3 * * * * - TV PROCESSOR - MICROCONTROLER - TXT - * * 3005 * UHF 3000 * 2002* * 2005 * 470N * * * 5010 1U2 * * * * * D31 * * * * * * * * * * * * * * * * E32 * E35 6. Electrical Diagram 1001 1015 1032 1033 1679 2001 2002 2005 2006 2010 2017 2018 2021 2023 2031 2032 2034 2036 2090 2091 2092 2102 2103 2104 2105 2106 2111 2290 2291 2292 2293 2298 2299 2301 2302 2303 2304 2305 2306 2307 2308 2309 2340 2366 2367 2403 2411 2412 2416 2417 2600 2601 2602 2603 2604 2610 2611 2612 2613 2622 2623 2628 3000 3002 3003 3004 3005 3006 3007 3008 3010 3014 3015 3017 3018 3019 3020 3022 3023 3025 3026 3027 3028 3030 3031 3032 3033 3034 3035 3101 3102 3103 J7 J6 K2 K2 C3 I8 J6 J7 K7 I2 K7 K6 K2 L3 K3 J2 J3 K1 J8 K8 K8 L6 L6 M6 L2 L5 M6 F2 H2 H2 G2 G3 G3 F6 F6 F6 G6 G6 G6 G6 H6 H6 K5 I6 I6 H9 H8 I8 G7 H7 D2 E2 B8 C2 C2 B8 B9 E3 D3 B3 B2 A2 K8 J9 J9 K9 J8 K9 K9 K8 L9 I5 J5 K6 K6 K6 K7 K3 K3 L2 K9 L2 L2 K1 K2 K2 K1 J2 J2 M6 M8 L8 3104 3291 3292 3293 3294 3295 3301 3341 3371 3372 3373 3402 3406 3407 3410 3411 3412 3413 3414 3415 3416 3495 3496 3601 3602 3603 3604 3605 3606 3607 3610 3611 3612 3613 3614 3615 3618 3621 3628 3629 3656 3663 3675 3682 3684 3685 5010 5032 5033 5301 5601 5602 5607 6020 6372 6413 6496 6602 7004 7005 7015 7104 7401 7601 7605 7685 9004 9016 9017 9061 9102 9103 9371 9401 9402 9403 9404 9414 9416 9417 9434 9435 9496 9536 9613 9618 9621 9656 9664 9665 9682 9695 M7 H2 F2 F2 F2 E2 G6 J5 M3 M2 M2 G9 H6 H6 F7 H8 I8 H9 G9 G8 H8 G2 F2 B9 B9 B8 B8 B8 B7 B6 B8 B8 B9 F8 E8 F8 B6 C2 B2 C3 C6 E8 E8 A5 A3 A2 J6 K2 J1 F6 E2 D2 B2 K7 M2 H8 F2 B8 K2 K1 G4 L7 G7 E8 B7 A2 J1 F6 E6 I7 K6 L8 M2 I6 I6 M3 M2 G8 G7 G9 H7 H7 G7 D1 C1 C7 C1 B2 D7 C7 A6 D1 6. Electrical Diagram 25KV 23 D41 FOCUS 1M1 51R 3205 2237 2N2 2208 10U 6230 BAV21 TP20 L1:1 3236 1K5 L3 +200 FOCUS D39 VG2 - DISPLAY - D40 COMPONENTS - D42 9230 RES 3206 1M +200 9226 - RGB & DISPLAY 1K5 VG1 VG2 3226 FF* FF L1:4 5235 FF GR RG 1K5 3229 2204 560P 5 7 100R 3228 6229 BAV21 8 +200 9 100R 3215 +200 6216 BAV21 +200 100R 3202 1K5 3216 AQUA 1M1 1K5 3203 6201 BAV21 Pos Pal BG Pal I Pal BG Pal I Mono Mono Stereo Stereo 1015 G1963 1032 5.5 Pos MONO 1W T630mA MONO 3W STEREO 4W+4W T1A T2.5A J1952 G1984 J1981 1540 6.0 5.5 6.0 2187 220U 220U 1000U 2540 680U 680U 1500U 3189 -- -- 1R Pos Mono Stereo 6450 BYT42M BYT42M BYW32 A1 YES -- 6540 BYT42M BYT42M BYV98 C3 -- YES 7187 TDA8941P TDA8943SF TDA8944J C4 YES -- C5 -- YES C6 -- YES E -- YES 2102 3N3 33P Pos 14" 20"/21" 2103 10U -- C1 YES -- 2105 2U2 -- C2 -MINI YES 2106 -- 22N 23 NARROW 2194 100U -- 2445 -- 220P 2196 -- 10N 2446 8N2 9N1 2860 4N7 -- 2448 10U 47U 3186 -- 0R05 3189 -- 1R 3191 68R -- 3214 560R -- 3196 -- 0R05 3217 560R -- 3197 0R05 -- 3220 -- 560R -- 560R * 33 L6 L1:3 +200 FF 2202 100N D37 B AQUA 3198 0R05 -- 3221 3199 0R05 -- 3415 4R7 3R3 3808 JMP -- 3416 4R7 3R6 3810 JMP -- 3444 5K6 2W 3856 -- 100K 3235 1R 0.3W 1R 0.5W 5538 JMP FERRITE 3457 27R 0.5W 47R PR01 9004 -- JMP 3460 7K5 6K2 9143 JMP -- 3480 -- 1K LOT 14" LOT 20" 3 L2:5 CUT_OFF A24 A28 A25 R_OUT RGB_GND L2:4 3217 * L2:3 3221 * 3220 * 2 3214 * L2:2 A26 A27 B_OUT G_OUT L2:1 560R 3207 * 1 4 7200 TDA6107Q 6 B6 D6 E3 E3 C6 C5 E2 E3 C8 C8 C6 C5 D8 D8 D8 D3 D6 D5 D3 E3 B5 C5 D5 F3 C6 D3 F3 D38 A-D 2202 2204 2208 2237 3202 3203 3205 3206 3207 3214 3215 3216 3217 3220 3221 3226 3228 3229 3236 5235 6201 6216 6229 6230 7200 9226 9230 5K6 3W 9144 JMP -- 5445 9151 JMP -- 5480 -- 57331 9450 -- JMP 5500 CU15 CU15D3 9802 JMP -- 5525 SOPS 14" SOPS 20" 9809 YES -- 9480 JMP -- HPH_R/SPKSW HPH_L HPH_MONO HEADPH_GND KEYBOARD LED 2194 3191 2685E 100U * * 3665 680R 9167 9166 9168 9169 3667 1K3 10U MAIN_L MUTE +11A E51 A3 +5B 3190 3189 9140 3147 100K 6147 * 9147 2147 LL4148 MAIN_R AUDIO_OUT HPH_MONO HPH_R/SPKSW C5 C50 A19 C19 C52 E48 C48 10K 24 25 26 3186 * 3199 +11B 3185 RES 7141 * BC847 10K 3145 * 3183 RES 0R05 3184 * 3196 * 2190 220N P+ P- MENU GND 220N 2181 * 3198 2192 10N 9687 9684 100R 3 1 2 10 +11B 2685 100U 11 * 3661 1K 3 2 1 1685 +11B +11B 4 3 2 1 9181 9170 MODE IN+ OUT+ VCC - 3841 * 100R IN- SVR 5 6 7 8 9151 9144 2182 10U 9143 SC_AUDIO_OUT_R OUT- +11B 3843 * 100R SC_AUDIOOUT B_EXT G_EXT RES 6857 * 9857 100R 3845 * SC_AUDIO_OUT_L GND E45 E46 A11 A23 A22 INT_CVBS - 7875 BC847 * 3170 3171 10K 2858 220P 220R 2857 3864 * 3860 * 220R 6852 * RES RES 6854 * RES 2179 220N 2197 RES 3855 * 2195 1N5 220P 68R 3875 * 2876 10U 3877 6856 * +8 +11B 2854 * RES C3 2860 9809 6851 * RES RES 6853 * RES 6855 * 3876 470R 3874 * SCART + AV R_EXT +8 A21 A16 +11B 7187 TDA8941P TP35 42 6663 B4_4534 +3V3 TSOP1836SS3V 20"/21" +3V3 3664 * 9685 9686 2196 GND +3V3 +3V3 3197 * 7140 * BC847 9114 3193 * RES 3194 * 3142 10K 2187 1000U 3141* 3140 22K 9113 48 6663E B4_4534 +3V3 TSOP1836SS3V 3 2 1 1685E - AMPLIFIER C4 E48 C48 E49 C52 E47 A2 A6 +3V3 100R 3664E * 3661E 1K * RC5 * * * * * A30 * * * * * * * * * C2 * * 75R 55 54 C6 GND 75R 75R 21 19 14" * 3853 * 3851* 3808* * 20 18 16 14 17 15 13 11 9 12 10 8 6 43 2183 1N5 +11B GND * * 3155 82R 2155 +11B 100N 220N *2184 220N 2193 * 3154 82R 2154 100N 3893* +8 3858 75R 6849 RES * 2852 2850 7 5 3 1 4 2 * * * * 3865 75R 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 BC847 9802 OUT1- GND1 VCC1 OUT1+ NC IN1+ NC IN1- IN2- MODE SVR IN2+ NC OUT2- GND2 VCC2 OUT2+ 1 2 3 4 5 6 7 8 9 AUDIO_EXT OUT- VCC OUT+ IN+ IN- SVR MODE GND NC IN AUDIO AUDIO_EXT_L 3810 AUDIO_EXT_R 3883 10K INT/EXT 3881 10K FB_EXT CVBS_EXT +8 6848 RES 7187B TDA8943SF 7187C TDA8944J 2859 RES 5K6 3850 * 2856 RES 5K6 3852 * 3880 5K6 +8 IN VIDEO 7876 * *3891 * 3879 * 47K * 220P 220P C1 * * * 100K * * * * * 3854 * 3856 * * * A - E - F A14 E44 E43 A4 A20 A18 6. Electrical Diagram 1685 1685 2147 2154 2155 2179 2181 2182 2183 2184 2187 2190 2192 2193 2194 2195 2196 2197 2685 2685 2850 2852 2854 2856 2857 2858 2859 2860 2876 3140 3141 3142 3145 3147 3154 3155 3170 3171 3183 3184 3185 3186 3189 3190 3191 3193 3194 3196 3197 3198 3199 3661 3661 3664 3664 3665 3667 3808 3810 3841 3843 3845 3850 3851 3852 3853 3854 3855 3856 3858 3860 3864 3865 3874 3875 3876 3877 3879 3880 3881 3883 3891 3893 6147 6663 C6 C8 K9 J3 L3 K4 J7 K5 K3 L3 M8 M8 G7 K3 G8 K3 G7 K4 C7 C9 F3 F3 G4 F2 G4 G4 F2 F4 C4 K8 K8 K8 K7 K9 J3 M3 K4 J4 J7 J7 L7 L8 M8 M8 G8 J8 J8 H7 G7 H7 H7 C7 C9 C7 C9 E8 F8 F3 F2 E5 E5 D5 F2 E3 E2 E3 F2 D3 F2 D3 F4 G4 C2 C5 C4 C4 B4 E2 E2 E1 E1 D2 G3 K9 D6 6663 6848 6849 6851 6852 6853 6854 6855 6856 6857 7140 7141 7187 7187 7875 7876 9113 9114 9140 9143 9144 9147 9151 9166 9167 9168 9169 9170 9181 9684 9685 9686 9687 9802 9809 9857 D8 C2 C2 F4 F4 E4 E4 D4 D4 D5 K8 K8 K6 K3 C4 E2 J8 J8 K9 J5 L5 K9 L5 H8 H8 G8 G8 M6 M6 C7 B7 B7 D7 G2 F4 D5 9503 22 1U 2440 * 2500 470N T 2 A H 1500 3440 * 100R 22U 5440 2 1 * KA5Q0765RT 3501 PTC RES 9505 5 4 3 6521 RES 2528 RES 2514 47U 2 M2:2 5K6 3W 3441 10K 2450 470N 3444 DEGAUSS 6440 LL4148 M2:1 4 5500 3 - POWER SUPPLY - M1:1 3504 10M M1:2 A12 LINE_DRV 3455 BF422 7514 3526 470R TP3 1 2 2442 560P 4 3 TP12 2527 47N 1N4148 6511 2510 1N B39 3511 3K9 7515 TCET1103G 9506 6524 1N4148 TP4 10R 3470 4R7 5525 3N3 2506 3238 2 4 12 10 3 5 1 9 +11 10 9 7 2 1 1K 3535 2446 7 M5:6 47U 3235 8 2458 10N 5447 7533 KA431LZ 3525 BYT42M 6470 TP5 2515 100U TP14 2448 2445 2505 68U B37 6523 BAV21 2470 10U BUT11AF 6525 BAV21 3522 M5:3 7445 2507 RES TP1 1K2 2524 3N3 TP2 M6:4 B38 3445 47R TP13 3480 9480 5480 6451 BYT42M 3442 5K6 5533 FERRITE 1 5441 7440 2444 47N 3451 33K 2451 10U 3456 100K 2449 10N M6:3 100K GND +101.5 SYNC 2504 FF H_FLYBACK FB 1N4007 1N4007 6447 A13 9501 VCC 2N2 2N2 2502 DRAIN 6505 6503 M6:1 1N4007 3527 1N4007 * 3528 FF BYD33M RES +200 270K 270K * 6504 * 4 5 3 6 8 2532 TP18 2539 * 22N 3542 1K 3539 270R 3519 4K7 3540 RES 3536 39K 2533 100U 7571 BC847 3573 0R05 2531 RES 3534 47K 6531 3531 180K TP19 +12B 6571 RES 9572 3533 22K +11 6463 3479 470R 3475 * 4R7 PR03 3530 9504 * 7572 * BC847 6474 C8V2 3474 56R 7478 BC337 5538 9542 3532 10K 3537 5K6 2561 22U TP37 TP38 BCL POR +3V3 STBY TP8 +11A A31 A29 +101.5A +11 TP7 TP6 +5 +8 +12 +45 A24 +101.5 TP39 2467 220U 6479 C5V6 2% 7479 BC337 390R 1/2W 390R 3478 * 4R7 3453 B42 FOCUS A15 B40 VG2 EHT B41 25KV 9464 2462 4U7 9450 1N4148 2540 FERRITE 7575 BC337 +8 3575 RES 1540 1N4148 +101.5 6540 470P * 100R RES 12K 3462 * 2454 220U 2455 470U 3541 BYT42M 6449 TP40 2530 47U 3572 5532 +11 FERRITE 3576 180R 6570 * 3V3 6450 2453 22U BYT42M 1R 3452 2460 47N 3460 +8 11 BYV95C 6530 3570 47R RES 3449 1R 1R 5449 47U 3450 BYT42M 6452 2534 3571 560R 9575 FERRITE 5534 5445 * * * * 6502 * * * * 9479 2562 +101.5 * 100N * * 3457 * * * * - LINE - * E 6. Electrical Diagram 1500 1540 2408 2440 2442 2444 2445 2446 2448 2449 2450 2451 2453 2454 2455 2458 2460 2462 2467 2470 2500 2502 2503 2504 2505 2506 2507 2510 2514 2515 2524 2527 2528 2530 2531 2532 2533 2534 2539 2540 2561 2562 3235 3238 3440 3441 3442 3444 3445 3449 3450 3451 3452 3453 3455 3456 3457 3460 3462 3470 3474 3475 3478 3479 3480 3501 3504 3511 3519 3522 3525 3526 3527 3528 3530 3531 3532 3533 3534 3535 3536 3537 3539 3540 3541 3542 3570 3571 H8 K3 B7 E8 E6 D7 D5 D4 B5 B5 C7 C6 D3 E2 F3 B4 C3 C2 E1 D5 H8 I6 H7 H6 I5 H4 I5 J6 J7 J5 K6 L6 L6 I3 L3 J3 K3 H3 L4 K2 I2 I2 E4 E4 E8 E7 E6 D7 D5 F3 E3 C6 D3 E2 C7 C6 B4 C3 C2 D4 F2 G2 E2 F2 C6 I7 I9 L5 L3 K5 J5 K6 I5 I5 H2 L3 L2 L2 L3 K4 L3 L1 K4 L3 I3 K4 J3 I3 3572 3573 3575 3576 5440 5441 5445 5447 5449 5480 5500 5525 5532 5533 5534 5538 6440 6447 6449 6450 6451 6452 6463 6470 6474 6479 6502 6503 6504 6505 6511 6521 6523 6524 6525 6530 6531 6540 6570 6571 7440 7445 7478 7479 7514 7515 7533 7571 7572 7575 9450 9464 9479 9480 9501 9503 9504 9505 9506 9542 9572 9575 I3 J3 J3 J3 E8 D6 D4 B4 E3 C6 H8 J4 K3 J6 H4 K2 E7 D4 F3 E3 C6 D3 C2 D5 E2 G2 I6 I6 H6 H6 K6 K6 J5 K5 J5 H3 L3 K3 J3 J3 E6 D5 E2 F2 J7 L4 L4 J3 L2 I3 E2 C1 F2 C6 H7 H9 H2 L7 K5 K2 L2 I4 C19 A19 A17 A35 A32 9727 GND 100R 3751 * 100R 3750 * GND RES 2742 * 3K3 3759* 2741 180P +5B +5B TP24 2753 470N * RES 2755 * FERRITE 5753 * 2751 100N 10K 3752 * TP31 TP27 1750 24.576MHz 1R *3753 3749 * 3K3 120P 5741 22U 3758 * +5B 9710 3741 6K8 27P 9740 2740 * AUDIO_OUT SIF SDA_2 SCL_2 9728 * 3748 * 2750 A - C * 470N - STEREO - 2754 1U 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 EXTIL EXTIR TEST2 MONOIN TEST1 SDI1 SDI2 SDO1 SDO2 WS SCK SYSCLK P2 XTALO XTALI Vssd4 CRESET Vddd1 Vssd1 ADDR2 SIF1 Vref1 SIF2 P1 Iref Vdec1 Vssa1 SDA SCL ADDR1 NICAM PCLK SCIR1 SCIL1 Vssd3 SCIR2 SCIL2 Vdec2 Vref(p) Vref(n) i.c. i.c. Vssa2 i.c. i.c. Vref2 SCOR1 SCOL1 Vssd2 Vssa4 SCOR2 SCOL2 Vref3 PCAPR PCAPL Vssa3 AUXOR AUXOL Vdda MOR MOL LOL LOR Vddd2 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 2U2 2769 * 2U2 2771 * 2R2 3774 33K 3769 18K 3772 33K 3771 18K 3770 * +5C 2758 470N 3756 270R 2759 47U 15K 3754 * 15K 3755 * 330N 2756 * 330N 2757 * 750R 2799 100U TP41 5702 JMP C45 C46 C47 C48 C49 C50 C51 AUDIO_EXT_R C43 C44 +5C +5B AUDIO_EXT_L 9704 2702 47U 9703 6702 C5V6 2% SC_AUDIO_OUT_L HEADPH_GND HPH_R/SPKSW HPH_L MAIN_R MAIN_L SC_AUDIO_OUT_R 9780 100U 0R05 3781 * 2798 3773 330R 1/4W 7702 BC635 3703 * 10R +12A 0R05 3780 * 3775 330R 1/4W TP26 TP25 3702 390R 1/2W 3704 2U2 2762 * 2U2 2764 * BC337 7780 +11B +12 BC337 7781 +11B +12 +5B +12 9701 9702 2760 47U 2761 470P 2763 470P 2765 47U 2766 10N 2767 10N 2768 10N 2770 10N 2772 470N 2773 10N 2775 10N 2777 470N 1R *3757 * * * * * * * * * * * * * * * * * * * * * 7701 TDA9875A 6. Electrical Diagram 1750 2702 2740 2741 2742 2750 2751 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2775 2777 2798 2799 3702 3703 3704 3741 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3769 3770 3771 3772 3773 3774 3775 3780 3781 5702 5741 5753 6702 7701 7702 7780 7781 9701 9702 9703 9704 9710 9727 9728 9740 9780 H7 I2 E8 F8 E8 C7 E7 G7 G7 L7 M3 M3 K4 J4 H4 H4 H3 G4 G3 E4 E4 E4 D4 D3 C4 C3 C4 C4 B4 A4 D2 C2 I2 I3 I3 F8 B8 B8 B8 C8 D7 F7 M3 M3 K4 A3 L8 F8 D3 C3 C3 D3 D2 D3 D2 C2 D2 I1 F8 F7 J2 G5 I2 D3 C3 I3 I3 I2 I2 M8 C8 B8 E9 E2 7.- CIRCUIT DESCRIPTION 7.1 SMALL SIGNAL &MICROCONTROLLER/TEXT(Diagram A) The small signal is processed by IC 7015. This IC called Ultimate One Chip ( UOC ) also has an embedded microcontroller. The CTU-AA chassis is designed to accept 2 different ICs in the position 7015, TDA9350 for TXT models and TDA9380 for no TXT. The associated circuitry is the same. The small signal part includes IF detection, video processing, chroma decoder, RGB , sync processor and sound decoder (mono sets). It is fully controlled by the embedded microcontroller. The microcontroller contains 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.). For stereo models sound decoder (IC 7101) is controlled also for IC 7015 by I2C bus. The IC for TXT sets (TDA9350) contains a teletext decoder, including the following functions: TXT on/off, reveal, freeze, temporary cancellation, clock, subcode, zoom, index, flof, page +/-, X/26 and 8/30 packet decoding (station identification and start-up page). Fig. 7.1 TDA 93XX block diagram 7.1.1 IF detection IF detection is intercarrier type, that means sound and picture are detected in the same circuit (PIF). - IF amplifier (pins 23, 24): The IF signal coming from pin 11 of the tuner (1001) is filtered by the IF SAW filter (1015) and applied to IF amplifier of IC7015 by means of pin 23 and 24 input. The IF bandpass characteristic is determined by the SAW (Surface Acoustic Wave) filter. - PLL demodulator ( pins 37, 58, 59): The IF-signal is demodulated with the help of a PLL detector, which one is used to regenerate the IF reference signal. Reference signal is determined by the PLL loopfilter pin 37 and calibrated by microcontroller x-tal ( pins 58, 59). It is alignment free. Demodulation is achieved by multiplying reference signal with the incoming IF-signal. - AGC (pin 27): The IF AGC time constant is internally fixed. The tuner AGC voltage (pin 27) is applied to pin 1 of the tuner and adjusted by microcontroller (see chap. 8.4). - Video output (pin 38) : This baseband CVBS signal with 2.5Vpp (sync inclusive) 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 Pal BG and 6.0 MHz for Pal I. 7.1.2 Sound processor Mono sets: - FM demodulation (pins 31, 29): FM sound is filtered from CVBS (pin 38) by a loopfilter (pin 31) and demodulated. Decoupling sound demodulator is made by a capacitor on pin 29. - De-emphasis and audio out (pin 28): De-emphasis is made by C2102 at pin 28. The signal at this pin is drived to the euroconnector sound output (see Diagram C) by transistor 7104 . - External audio in (pin 35): 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 I2C (see INT/EXT, chapter 7.6). - Audio out (pin 44): After a volume control (by I2C), this output is drived to the input IN+ of the final sound amplifier IC7187 (Diagram C). Stereo sets: SIF signal (pin 38): Video signal containing sound signal is drived to sound stereo processor IC7101 (see chapter 7.6 and diagram E) 7.1.3 Video processing - Video switches (pins 40, 42): The internal CVBS signal proceeding of pin 38 is now fed to pin 40 of 7015. External CVBS proceeding from pin 20 of Euroconnector is present on pin 42 of 7015. The IC switches between internal and external are controlled by I2C bus (see INT/EXT, chapter 7.1.8). The selected CVBS signal is internally supplied to the synchronization , teletext acquisition circuits and the video identification circuit for IF ident. - Luminance processor: CVBS is also internally applied to luminance processor, which is composed of chrominance trap filter, luminance delay line and peaking circuits. Sharpness control modifies peaking by I2C. 7.1.4 Chroma processing This circuit is an internal (no pins associated) automatic decoder for Pal and NTSC systems commanded by I2C bus. - ACC and chroma filter: Video signal coming from video switches is supplied to PAL/NTSC chroma bandpass filter via a variable gain amplifier which is controlled by ACC and ACL detection circuits. The dynamic range of the ACC is 26dB and detects only the burst amplitude. The ACL is a chroma amplitude detector and is active when the chroma/burst ratio exceeds approximately 3. It ensures that CVBS signal to chroma bandpass filter is limited for large. - PLL/DCO: Chroma PLL is integrated and it operates during the burstkey period; the DCO (digital controlled oscillator) generates a subcarrier signal Fsc in phaselock with the incoming burst signal. The reference signal for the DCO (Fref.) is derived from the crystal oscillator (1679). Different colour frequencies are internally switched by I²C. The hue control rotates the DCO reference phases (H0, H90) from -40 to 40 degrees for NTSC signal via I²C bus. - PAL/NTSC demodulation: The 0ª & 90ª signals are supplied to the burst demodulator circuits to obtain (B-Y) and (R-Y) respectively. Chroma delay lines used in demodulators are internal. 7.1.5 RGB processor - External RGB inputs (pins 46, 47, 48): RGB inputs coming from euroconnector (see diagram C), are AC coupled (C2291/92/93) and converted internally in YUV signals. Then are switched with internal YUV (YUV SWITCH) by fast blanking. - Fast blanking external (pin 45): 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: After switching, YUV signals are converted to R-Y, G-Y and B-Y in the internal MATRIX circuit. Saturation control is received by I2C bus. - Black stretcher: Internally the luminance signal is connected to the YUV select circuit and via the input clamps it is supplied to the black stretcher. The black stretcher circuit, fully integrated, extends the grey signal level . This extension is dependent upon the difference between actual black level and the darkest part of the incoming video. RGB adder: RGB signals are obtained in this circuit by adding R-Y, G-Y and B-Y proceeding from matrix and Y proceeding from black stretcher. - RGB OSD: RGB inputs for OSD and TXT are internally inserted to RGB signals. Fast blanking used is also internal. 45). - Beam current limiter (pin 49): The beam current limiter circuit functions as an average beam current limiter (BCL) as well as peak white limiter (PWL). Both functions reduce the contrast and brightness of RGB signals. Contrast reduction begins when Vpin 49 < 3.1V and brightness reduction begins when Vpin 49 < 1.8V. BCL: Average beam current present at pin8 of 5445 (Diagram D) is feedback to pin 49. When beam current is high, voltage of C2462 is lower, D6462 conducts and Vpin 49 decreases. PWL: This circuit is an internal detection circuit, which comes into action if the difference between measurement DC level and white level exceeds approximately 2.6V. Then a current of 200µA is internally produced to discharge 2298 and Vpin 49 decreases. - RGB output circuit (pins 51, 52, 53): RGB outputs are drived to RGB amplifier (Diagram B). - Continuous Cathode Calibration (CCC) (pin 50): This circuit is an auto-tuning loop which stabilizes the black level (offset) as well as the cathode drive level (gain) of each gun. Pulses in 3 consecutive lines R, G and B (pins 51, 52, 53) at the end of frame blanking are used on alternating fields, one field for black level, following for cathode drive level. Cathode currents of 8mA for black level and 20mA for cathode drive level are stabilized. Cathode current is present at pin5 of IC7200 (Diagram B) and measured on pin 50. RGB outputs are adapted to keep cathode currents measured, for example when VG2 voltage is adjusted, DC level of RGB outputs is automatically corrected. - Warm-up detection circuit (pin 50): At the start up a DC voltage of 2.5V is present in the RGB outputs (pins 51, 52, 53). As soon as beam current is detected on pin 50, 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: The horizontal oscillator starts is commanded by microcontroller. During start up circuit provides a softer operating horizontal output with a higher frequency. - Hor. sync. separator: Fully integrated sync. separator with a low pass filter, slicing level at 50% of the synchronized pulse amplitude. - Horizontal Phi 1 detector (pin 17): This circuit locks the internal line frequency reference on the CVBS input signal. It is composed of a phase comparator and an internal VCO of 25MHz (1600*15625). The free running frequency is stabilized using the 12 MHz reference of the X-tal oscillator. Phi 1 detector filter is made by external components at pin 50. Phi 1 time constant is automatically controlled by software for broadcasting signals. For video signals (AV and program 99) constant is always fast to prevent top bending on the screen. - LBF (pin 34): Line Fly Back input, is obtained by the network R3456/55 (Diagram D) and R3371/T7372. - Sand Castle (pin 34): Sand Castle output obtained at this pin is used only internally. Levels of sandcastle pulse are 5.3V for burst detection, 3V for line blanking and 2V for frame blanking. - Horizontal Phi 1 detector (pin 16): The flyback position respect line blanking on TRC cathode is controlled by this circuit. Phi 1 detector filter is made by C2305 pin 16. Horiz. shift can be adjusted by I2C ( see chapter 8) - HOUT (pin 33): Horizontal output is an open collector which one drives the horizontal driver stage (T7440 diagram D). 7.1.7 Vertical synchro and vertical drive - Vert. sync. separator: It is an internal integrator to separate frame sync. pulses from CVBS. - Vertical divider system: The divider system uses a counter that delivers the timing for the vertical ramp generator in the geometry processor. The clock is derived from the horizontal line oscillator. Mode used is automatic 50/60Hz identification with 50Hz priority. - Vertical sawtooth generator (pin 25, 26): A reference current of 100mA is realized at pin 25 by means of an internal reference voltage (3.9V) and resistor R3341. This 100mA reference current is used to derive a 16mA current to charge C2340 (pin 26) during vertical scan. The charge current can be adjusted with the I²C bus control, (VERT. SHIFT). The external capacitor is discharged during vertical retrace by the vertical divider system. - Vertical geometry processor: The saw tooth signal that is derived from the sawtooth generator can be controlled by I²C bus. Control adjustments are: S-CORRECT, VERT.SLOPE, VERT.AMP and VERT.SHIFT (See chapter 8). - Vert. output stage (pins 21, 22): The vertical geometry processor has a differential current output to drive a DC coupled frame deflection (7401). - EHT compensation (pin 36): A voltage inversely proportional of beam current, proceeding of pin 8 of line transformer (5545 diagram D) is applied to pin 36 to stabilize vertical amplitude from EHT variations. - Vertical guard input (pin 50): A vertical retrace pulse proceeding from pin 8 of IC7401, is added to cut-off voltage at pin 50 (this pin has 2 separated functions, cut-off function see chapter 7.1.5). If there is not pulse or its level is not correct (should be above 3.65V, 0.8msec.), the set goes to standby mode. (See chapter 7.7.1 Protections). 7.1.8 Microcontroller/ Text Following there is an explanation of the different functions of the microcontroller indicating pins number assigned: - Tuning (pin 4): The unit has a VST (Voltage 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 0V to 33V applied on pin 2 of the tuner. It is generated on pin 4 of the µC and converted to an adequate level for the tuner using T7605. While searching, µC are always reading internally AFC (Automatic Frequency Control) and video identification signals. When video signal is identified, µC stops searching and do a fine tuning to reach a right AFC value. - Control key (pin 5): Pin 5 is activated by a DC voltage. When control keys are not activated, a voltage of 3V3 is produced by R3618. If one control key is activated, this pin is connected to ground directly or by a resistor R3665, R3667 (Diagram C), decreasing its voltage. There are 3 voltage levels depending of the key used: 0V for MENU, 1V for P- and 1.9V for P+. - Mute output (pin 6): This pin is a 3 state output used to control the sound amplifier (see chapter 7.4). States are 0V, open and Vcc (3.3V). - INT/EXT input (pin 7): 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 IC switches internally video and audio to external. In both cases the user can switch to internal changing the channel. - Band switching (pin 8, 11): There are 2 outputs for band switching pin 11 for VHFI and pin 8 for VHFIII. The µC controls the channel band in the tuner by a voltage of +5V at the correspondent output. UHF band is controlled by means of transistor 7601. If the set is in VHF, one of the pins 8 or 11 are high and transistor conducts in such a way the UHF voltage is 0V. If the set is in UHF, pins 8 and 11 are low, transistor is cut and the set is in UHF. - LED (pin 10): The LED (D6663 diagram C) 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. - Picture controls (brightness, contrast, colour, sharpness) are processed internally by I2C bus. - Sound controls (pins 2, 3): Mono sets: Sound controls are processed internally by I2C bus Stereo sets: All information necessary to control stereo functions including sound controls, are processed by a communication I2C bus between the µc and the stereo decoder (IC 7101 pins 4, 5). - Standby (pins 1, 33): When the set is switched to stand by, line stops (pin 33). In addition to this, pin 1 switch to low level to make Power Supply in burst mode (see stand by 7.5.3). - OSD outputs: The RGB and fast blanking signals used for On-Screen Display (OSD) and also for TXT are internally inserted to RGB outputs (pins 51, 52, 53). - Oscillator (pins 58, 59): A 12-MHz oscillator is determined by a 12-MHz crystal (1679) between pins 58 and 59. - P.O.R (pin 60) . : Power on reset (POR) is internal, activated when the set is switched on. If the µC shows abnormal behaviour it is advisable to reset it switching off/on the set. Reset can be done also by a short circuit between pins 60 and 61. - RC5 (pin 62): The commands transmitted by the remote control handset are received by infrared receiver (1685) and passed to the microcontroller for decoding. - EEPROM (pins 63 and 64): The microcontroller is connected to non-volatile memory IC7685 (EEPROM) via bus I2C. The 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. 7.1.9 Supplies and decoupings - Small signal analog supply (pins 14, 39): The same +8V supply coming from line deflection is connected to pins 14 and 39 for small signal processing. A separated supply (C2036) feeds video and sound traps circuit. If +8V supply is not present at pin 39 or pin 14 during the first 4 seconds after switch ON the TV set, the microprocessor goes to Standby mode (See chapter 7.7 Protections) . - Digital supply (pins 54, 15): A +3V3 supply is used for digital circuit of TV processor (pin 54). A decoupling capacitor for this supply is present at pin 15 (C2301). Pin 54 is used also to supply the µC. - Bandgap decoupling (pin 19): The bandgap circuit provides a very stable and temperature independent reference voltage of 4.0 V which one is used specially in the analogue video processor part. - µC supplies (pins 54, 56, 61): The µC has several +3V3 supplies, − Pin 54: Analogue supply (Oscillator, ADC). − Pin 56: Digital supply to µC core. − Pin 61: Supply to all output ports of theµC. When the set is in stand by, the µC switch to stand by mode, only 3V3 supplies are present but consumption is reduced. 7.2 RGB AMPLIFIERS (diagram B) The RGB signals available at pins 51, 52 and 53 of IC7015 (Diagram A) must be amplified and inverted in order to reach the level required for driving the tube. The integrated circuit IC7200 (TDA6107) is used for this purpose. RGB inputs (pins 2, 3, 1): These signals are connected to negative inputs of internal operational amplifiers. There is and internal reference voltage of 2.5V for the amplifiers. Negative feedback of amplifiers are internal resistors. RGB outputs (pins 8, 7, 9): These outputs are applied to the RGB cathodes of the tube. Clamping diodes to +200V (6201, 6216, 6229) and 1K5 series resistors (3203, 3216, 3229) are added for flash-over protection. - Continuous Cathode Calibration (CCC) (pins 50): This circuit is an auto-tuning loop which stabilizes the black level (offset) as well as the cathode drive level (gain) of each gun. Pulses in 3 consecutive lines R, G and B (pins 51, 52, 53) at the end of frame blanking are used on alternating fields, one field for black level, following for cathode drive level. Cathode currents - Cathode current feedback (pin 5): Cathode current used in Continuous Cathode Calibration circuit (See 7.1.5) is obtained at this pin and feedback to pins 50 of IC7015 (Diagram A) - White adjustment: Gain and cut-off point of RGB amplifiers can be adjusted by I2C in the service menu (See chapter 8) - Anti-spot circuit: When the set is switched off, the capacitor 2208 keeps charged and a negative voltage is put at VG1 of the tube. 7.3 DEFLECTION (Diagrams A, D) 7.3.1 Frame deflection (Diagrams A) Full bridge vertical deflection output performed by the integrated circuit TD8357J (7401). - Frame supplies (pins 3, 6): There are 2 supply voltages, +12V (pin 3) is the main supply and +45V (pin 6) is used to supply the output stage during flyback time. - Vertical inputs (pins 1, 2): (pins 21, 22): The output currents proceeding from pins 21, 22 of IC7015 are converted to voltages by resistors R3411/12 in such a way that 2 inverted sawtooth are present in the differential inputs of amplifier (pins 1, 2). - Vertical outputs (pins 4, 7): Vertical output is DC coupled to deflection coil. That means linearity adjustment is not necessary. HF loop stability is achieved by a damping resistor R3413. - Feedback input (pin 9): A voltage proportional to current deflection is present in R3415/16 and a feedback to pin 9. - Vertical flyback: This signal is internally added to vertical output (pin 7) using supply voltage at pin 6. - VGUARD circuit (pin 8): This circuit generates a high level during flyback period, and is used to protect the TV set in case of a vertical failure. (See protections, chapter 7.7) 7.3.2 Line deflection (Diagram D) 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 IC7015 (pin 33). The horizontal deflection stage is carried out in a conventional way, with the deflection transistor (T7445) and line transformer (5445). Beam current info (BCI) is present at C2460. There are the following supply voltages obtained from line transformer (5545): - Frame supply (+12B):Main frame supply present at capacitor C2455. - Flyback frame supply (+45 ): Flyback frame supply present at capacitor C2455. - +8V stabilizer: +8V for small signal is made from +12V (C2454) by D6474 and T7478 - +5V stabilizer: And additional voltage of +5V for small signal is made also from +12V (C2454) by D6479 and T7479. - Stereo supply (only stereo models): +12V from C2454 is drived to 7702 (Diagram E) to stabilize +5V for stereo decoder (7101. - FF : The heather voltage is reduced by R3235/38 and 5235 (Diagram B) to obtain 6.3Veff at the CRT . 7.4 SOUND AMPLIFIER (Diagram C) Sound amplifier is a Bridge Tied Load (BTL) amplifier including short circuit protection, mute and stand by mode. IC used can be TDA8941P for 14" and 17" models, TDA8943SF for 20" and 21" models or TDA8944J for stereo models. Behaviour is the same for 3 models. TDA8944J is a double amplifier, that means 2 supplies, 2 inputs and 2 outputs. - 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 (C2182). - Sound input (IN+): Amplifiers have differential inputs (IN+,IN-). Audio input is connected to IN+ decoupled by 220nF capacitor (C2181/84) and IN- is decoupled to ground by other 220nF capacitor (C2179/93). To avoid oscillations there is a 1n5 (C2183/95) capacitor connected between both inputs. - Mode input (MODE): This input is commanded by mute signal proceeding from the µC (pin 6 of 7015 diagram A) and has three modes depending of the voltage level: - Standby mode (Vmode = Vcc): Consumption is very low (used during stand by). In this case Vmute=0V, T7657 and T7659 are cut, MODE signal is high - Mute mode (2.5V<Vmode<Vcc): No sound output (used when the set is switched on/off, there is no signal, channel search, change of program, etc.) In this case pin 6 of 7015 is open T7659 conducts (by resistor divider), T7657 are cut, MODE voltage is 5,5V. - Operating mode: (Vmode<0.5V): Sound output present (normal operation). In this case Vmute=3V3 both transistors conduct, mute signal is low. - Sound output (OUT+/OUT-): Amplified sound is drived to the loudspeakers. Mono sets: Headphones output has been connected in such a way that when headphones are connected, loudspeakers are switched off. Stereo sets: Headphones output are coming directly from pins 57 and 58 of stereo decoder IC7101 (see chapter 7.6 and diagram E). 7.5 POWER SUPPLY (Diagram D) Mains isolated switched mode power supply (SMPS). controlled in variable frequency mode. IC7514 (KA5Q075RT) includes control circuit and output MOSFET. Output feedback is done by means of an optocoupler (7515). - 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 in stand by. Standby is done cutting line deflection and making the supply in burst mode in such a way that power consumption is very low. 7.5.1 Degaussing and Rectifier - 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 Regulation - Power MOSFET (pin 1): Power stage is done by an internal MOSFET between pin1 and ground. Current is sensed by an internal resistor and limited to 5A peak. (See chapter 7.7.2 Protections) - Start up and supply (pin 3): When the set is switched on, a current via R3527 and R3528 is applied to pin 3. When C2514 is charged to 15V, the power supply starts and the internal MOSFET conducts. A voltage across transformer windings is built up. The voltage across winding 4-2 is rectified by diodes D6523/25 and used to supply the IC on pin 3. Voltage of pin3 depends on the output voltage and is about 28V. If Vpin3 is lower than 9V supply stops and if it is higher than 32V, output voltage is limited. (See chapter 7.7.2 Protections) - Sync (pin 5): A pulse voltage proceeding from winding 4-2 is applied to this pin. A delay is added by means of C2524, R3522 and R3526 to synchronize starts conduction of MOSFET at minimum Vds voltage. - Secondary feedback (pin 4): Line supply feedback is obtained at pin 4 by divider R3531/34/19, the differential amplifier (IC7533) and the optocoupler (IC7515). Voltage at this pin is about 1.1V - Output regulation: IC7514 stabilizes output voltage by controlling T-on and so the frequency and the duty cycle. Output control is done by the following way: If line output is higher, current input of the differential amplifier (IC7533) is higher (amplifier has a reference voltage of 2.5V). Current in IC7533 and also in the optocoupler (IC7515) is higher. Voltage in pin 4 is lower, T-on is internally reduced and output is reduced. Output voltage of supply can be adjusted by R3518. 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 P3534. - Sound supply (+11V): This supply is used for sound output amplifier and to feed 3V3 stabilizer. - µC supply (+3V3): +5V3 is regulated by T7575, D6570 and T7571. 7.5.3 Stand by: When the set is put in standby, line driver (pin33 of IC7015, diagram A) stops and deflection supply is not loaded. Only a reduced load to supply the µC (+3V3) is necessary. To reduce more the power consumption, during standby T7572 is cut by STBY signal (pin1 of IC7015, diagram A), then current in IC7533 is increased by means of D6531 and output voltages are reduced. As a consequence of this, the supply switch to burst mode operation. During working time C2514 is charged till 12V, then supply stops and C2514 is discharged till 11V. 7.6 STEREO DECODER The CTU Stereo chassis is based in the TDA9875A chip. This is a single-chip Digital TV Sound Processor for analog and digital multichannel sound systems in TV sets. In the stereo chassis the sound part in the IC7015 (TDA9350) is disabled. All sound signal, analog and digital is processed in IC7101 (TDA9875A). The TDA9875A decodes NICAM signals (B/G and I standard) and two-carrier FM modulation A2 signals (B/G standard). - Control bus (pins 4, 5): Stereo is fully controlled for the µC of IC7015 (Diagram A) via I2C-bus. Status information present in internal registers of IC7101 is read by µC to determine whether any action is required. Control is exercised by the µC also, writing in other internal registers of IC7101. This control includes volume, balance, bass, treble, pseudo stereo, spatial, and Automatic Volume Level (AVL). - Oscillator (pins 18, 19): The circuitry of the crystal oscillator is fully integrated, only a external 24.576 MHz crystal is needed. - SIF input (pin 12): SIF signal is filtered from video signal coming from pin 38 of IC7015 (Diagram A) by a passband 5.5MHz to 6.5Mhz filter (C2740/41/42 and L5741). - AGC, ADC: SIF is passed through an AGC circuit and then digitized by an 8-bit ADC operating at 24.576 MHz. The gain of the AGC amplifier is controlled from the ADC output. Then signal is separated in 2 ways, one for FM and other for NICAM. - FM demodulation: FM signal is fed via a band-limiting filter to a demodulator. If signal is stereo A2, decoder recovers the left and right signal channels from the demodulated sound carriers. A stereo identification signal is sent to the µC. - NICAM demodulation : NICAM signal is transmitted in a DQPSK code at a bit rate of 728 kbit/s. NICAM demodulator performs DQPSK demodulation and feeds the resulting bitstream and clock signal onto the NICAM decoder. A timing loop controls the frequency of the crystal oscillator to lock the sampling rate to NICAM decoder: The device performs all decoding functions in accordance with the “EBU NICAM 728 specification”. - Audio processing: After demodulation, digital signal is selected (FM, A2 or NICAM) and processed according µC control. Following functions are provided: Forced mono, stereo, channel swap, channel 1, channel 2, spatial effects, Automatic Volume Level (AVL), volume, balance, bass and treble. - DACs (pins 54, 55): Then signals are transformed to analog by DACs and sent to the outputs. Post filter capacitors for DACs are at pins 54 and 55. - Sound outputs (pins 60, 61): After a volume control (by I2C), sound outputs (MAIN R and MAIN L) are drived to the inputs IN+ (pins 12 and 6) of the final sound amplifier IC7187C (Diagram C). - Headphone outputs (pins 57, 58): Headphone outputs are drived by followed emitters 7780 and 7781 to the headphones. These outputs are independent of loudspeakers outputs and controls are separated. - External audio out (pins 47, 48): Signal at these pins are drived directly to the euroconnector sound outputs (see Diagram C). - External audio in (pins 33. 34): External audio (R and L) proceeding of pins 6 and 2 of euroconnector (Diagram C) is applied pins 33 and 34 of IC7101 and digitalized by an ACD circuit. Selection between internal or external is done from the µC (IC7015) by I2C bus (see INT/EXT, chapter 7.6). - External audio out (pins 47, 48): Signal at these pins are drived directly to the euroconnector sound outputs (see Diagram C). - +5V stabilizer: +5V supply for stereo processor is obtained from +12V (C2454 diagram D) by D6702 and 7478. This voltage comes to supply voltages of IC1701 (pins 59, 15, 64) - Digital supplies (pins 15, 64): +5V supplies at pins 15 and 64 are used for digital circuits of stereo processor. Power ON reset (pin 16): When the set starts, C 2754 is slow charged by an internal 50K resistor to +5V. When digital supplies are present and oscillator is working, reset is done if pin 16 is low (Vpin16<1.5 V). - Analog supply voltage (pin 53, 59): There is a +5V supply for analog outputs (DACs and operational amplifiers) at pin 59. A 50% reference voltage (2.5V) for these circuits is present at pin 53. - ADC supply voltage (pins 38, 39, 40, 46) : A 3.3V supply voltage is obtained internally and decoupled on pin 38 by C2758. Positive and negative reference voltage for ADC is present at pins 39 and 40. A 50% reference voltage (1.65V) for ADC is present at pin 46. - Front-end supply (pins 7, 8, 11) : A separated 3.3V supply voltage (decoupled on pin 7 by C2750) is necessary for SIF demodulator. By means of a 200mA current generator at pin 8, a 2V reference voltage is produced at pin 7. 7.7 PROTECTIONS If TV does not start or it switches to stand by, try to start again in a few minutes and if problem remains check protection pins explained following. 7.7.1 Protections in IC7015 (Diagram A) - Pins 14, 39: If +8V supply is lower than 6V (pin 39 or pin 14) during the first 4 seconds after switch ON the TV set, the microprocessor goes to Standby mode (See also chapter 7.1.9). - Pin 50: If the vertical retrace pulse at this pin is not correct (should be above 3.65V, 0.8msec) during the first 4 seconds after switch ON the TV set, the vertical guard blanks the RGB outputs and the TV switch to Standby (See also chapter 7.1.7). This protection operates in the following situations: - When the vertical deflection fails and there is no pulse. - When the vertical retrace pulse is higher than 0.9msec. (for example vertical amplitude is too high) - An extra protection is obtained when there is too much current in the CRT (for example +200V supply is missing), because in this case, DC level of pulse is lower by means of cut-off signal. (See fig. 7.7.1) 6v 3.65v 3.65v 2,8v Correct Vertical Deflection 3,2v Failure 0.8v 0 mS 20 mS 0 mS 20 mS Fig 7.7.1 Vertical guard protection To repair the set more easily, Vguard protection can be disabled, in this case the vertical guard blanks the RGB outputs, but TV does not enter in Standby mode. To disable Vguard, item 8 of Service menu MANUAL C-O should be 01 (See chapter 8.1). Due to a change in MANUAL C-O is difficult to do if the set switch to Standby, Vguard can be disabled also connecting a diode (1N4148) in series with a 2K2 resistor between pins 10 and 7 of IC7015 (Anode at pin 10). Be careful to disconnect this network after the set is repaired. 7.7.2 Protections in IC7514 (Diagram D) - Pin 1: Primary current is sensed by an internal resistor for the IC. If this current is increased to 5A peak, supply works in a intermittent way (ON and OFF). That can be provoked for a short circuit on secondary outputs. - Pin 3: If Vpin3 is lower than 9V the under voltage protection stops the supply. If Vpin3 is higher than 32V over voltage protection limits output voltage. 8.- ELECTRICAL ADJUSTMENTS 8.1 Service mode The signal processor IC7015 is fully controlled by I2C, so that the most of adjustments of the set can be made by service menu. - Enter in Service mode: - Select program 75 and press 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. Note : Controls (volume, contrast, brightness and saturation) will be pre-adjusted to the mid position. - 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 Nº Description Value ITEM Hexa Nº Description Value Hexa 1 ADJUST VG2 PRG 13 R GAIN 20H 2 CATH.DRIVE 0CH 14 G GAIN 20H 3 TXT V-SHIFT 02H 15 B GAIN 20H 4 TXT H-SHIFT 02H 16 S-CORRECT 20H 5 V-GUARD DISA PRG 17 VERT.SLOPE 20H 6 AGC START 25H 18 HOR.SHIFT 20H 7 RESERVED 19 VERT.AMP 20H 8 MANUAL C-O 01H 20 VERT.SHIFT 20H 9 R CUT-OFF 20H 21 SYS OPTIONS 00H 10 G CUT-OFF 20H 22 MENU OPTIONS 00H 11 BRIGHTNESS PP 23 READ STATUS PRG 12 CONTRAST PP 24 RESERVED 00H Table 8.1. Service menu. Settings are hexadecimal values - Pre setting values: When E2PROM is replaced, pre-setting values indicated on table 8.1 are stored by the µC. (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 2, 5, 23 and 24 have fixed values = pre setting values, rest of items see 8.2 to 8.6. - 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 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 R3534 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. 8.3 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. 8.4 White D 8.4.1 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) 8.4.2 Grid 2: - Connect a white pattern generator. - Adjust contrast at 00 and brightness at 36. (00 and 24 in the service menu because hexadecimal values are used - Put parameter 1 of the service menu ADJUST VG2 = 1. An arrow will be displayed on the left upper corner. - Adjust VG2 potentiometer ( in line transformer ) till the arrow will be transformed to a square. - In a few seconds, arrow will be disappear and ADJUST VG2 parameter will be come back to 00. 8.4.3 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 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. Adjust to have picture centred in vertical position by service menu item 16. - 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. Adjustments only if necessary: - TXT Shift: Vertical and horizontal shift of OSD or TXT can be adjusted by items 3 and 4 of service menu. - Vertical slope: When item 17 is selected, only upper part of the screen can be seen. Vertical slope is adjusted when centre line of the pattern is just visible. - Vertical S correction: S correction 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: SYSTEM OPTIONS (Item 21) VALUE MENU OPTIONS (Item 22) VALUE PAL B / G 00 16 Languages menu 00 PAL - I 01 English bars menu 01 Global menu (without languages ). 03 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 Example: S01M00 means system = 01 (Pal I) and menu = 00 (13 Languages menu) When the chassis or the EEPROM (IC7685) have to be replaced, be careful to keep the same type of chassis, setting correctly the chassis options. 8.8 Error messages The microcomputer also detects errors in circuits connected to the I2C (Inter IC) bus. These error messages are communicated via OSD (On Screen Display) : Error message Error description Component F2 Eprom communication error IC7685 F3 µC internal error (RA M) IC7015 (µC) F4 Internal bus communication IC7015 SDA2/ SCL2 bus wrong communication IC7101 (stereo) SDA2/ SCL2 bus no communication IC7101 (stereo) F5 No sound menu F6 Eprom data error IC7685 F7 Not allowed options * Item 21,22 service menu. F8 Vertical guard pin 50, IC7015 * If SYS OPTIONS or MENU OPTIONS are not possible in this chassis, the µC change to allowed options and first time TV set is switch on F7 message is displayed. Options should be checked ( see 8.7) 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 ! should be replaced by components identical to the original ones - When replacing the CRT, safety goggles must be worn. 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 0V (after approx 30s). 2. ESD. All IC'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. 2. Safety regulations require also that after a repair: - The set should be returned in its original condition. - Τhe 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 secondary 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, flyback capacitor. 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 an IC 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). 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. 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. The picTure tube PWB has printed spark gaps. Each spark gap is connected between and electrode of the picture tube and the Aguadog coating. FIG. 9 21
