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Sharp 20CT-250, Service Manual

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Sharp 20CT-250 Service Manual Download Page 16

16

16-1

16-2

20CT

-250

TROUBLE SHOOTING TABLE 

(Continued)

NO SPECIFIC COLOUR

Is some colour produced in 
B/W broadcast reception ?

Is the white balance properly 
adjusted ?

Readjust the white balance.

The picture colour is yellow.

The picture colour is magenta.

The picture colour is cyan.

Check Q851 and its 
adjacent circuits.

Check Q852 and its 
adjacent circuits.

Check Q853 and its 
adjacent circuits.

Check IC801 and bias 
control circuit.

Normal

Normal

“SECAM”

“PAL”/“NTSC”

NO SPECIFIC COLOUR

“PAL”/“NTSC”/“SECAM”

(NO COLOUR SYNCHRONIZATION)

NO

YES

YES

NO

Check IC801, R809, R810, 
R811, D801, D802, D803, 
Q801, Q802, Q803,Q804 
and Q805.

Check X801, C810, C815, 
C816 and R814.

Check C901 and pin (31) of 
IC1001.

TROUBLE SHOOTING TABLE 

(Continued)

NEITHER VERTICAL NOR

HORIZONTAL SYNCHRONIZATION

CIRCUIT TO BE CHECKED:

»

 Sync. Separator Circuit.

NO VERTICAL SCAN

Vertical linearity is abnormal.

Check C515, C519, R511, 
R513 and R514.

Vertical size is abnormal.

Check R510, C513, C514 
and C501.

Check IC801 and Q401.

DEFECTIVE VERTICAL AMP.

AND VERTICAL LINEARITY

Readjust vertical size.
(Bas Data)

Check IC501.

Check C506.

Check IC501 bias.  

Normal

Abnormal

Summary of Contents for 20CT-250

Page 1: ...VICE ADJUSTMENT 6 TROUBLE SHOOTING TABLE 15 SOLID STATE DEVICE BASE DIAGRAM 18 Page CONTENTS Page SHARP CORPORATION Ë Full Auto Channel Preset And Auto Channel Skip Ë 100 CH Program Memory Ë Aperture Control Circuit Ë Black Stretch Circuit Ë Bilingual System Mono Ë Auto Channel Scan System Ë Favorite Channel Memory System COLOUR TELEVISION Chassis No G2 SERVICE MANUAL S88U521CT 250 CHASSIS LAYOUT ...

Page 2: ...sibility that the high voltage fluctuates as a result of the repairs never forget to check for such high voltage after the work 3 Do not substitute a picture tube with unauthorized types and or brands which may cause excess X ray radiation BEFORE RETURNING THE RECEIVER Before returning the receiver to the user perform the following safety checks 1 Inspect all lead dress to make certain that leads ...

Page 3: ...ys on the remote controller the data can be modified 5 Set the switch S1006 to the normal mode OFF position and the microprocessor is put out of the service mode 2 Factory presettings 1 Set the switch S1006 to the service mode position and turn on the main power switch Initial values are automatically preset only when a new E2 PROM is used judgment with the first 4 bytes 2 The initial data are pre...

Page 4: ...1 KEY 2 KEY 3 KEY 7 KEY 8 KEY DOWN 4 KEY 5 KEY 6 KEY F B KEY 0 KEY CUT OFF BKGD mode LATERAL mode R DRIVE B DRIVE CUT OFF mode 50 Hz ADJUST mode COLOUR ADJUST mode 50 Hz ADJUST mode COLOUR ADJUST mode Y DY OP ADJUST mode 60 Hz ADJUST mode SUB ADJUST mode In the direction of arrow CH DOWN key In the opposite direction CH UP key CUT OFF BKGD mode 3 sec time out 3 sec time out 3 sec time out 3 sec ti...

Page 5: ... PAL TV AV 0 7 2 2 2 DT SECAM TV AV 0 7 4 4 2 DT NTSC TV AV 0 7 2 2 2 DT B W TV AV 0 7 2 2 2 V MUTE ON OFF OFF A V 2 1 2 1 NVM With all the adjustments complete do not change the data of addresses 00H thru 03H Other wise the E2 PROM will be initialized when the AC power is turned on 1 These data are additionally adjusted for 60Hz based on the 50Hz settings 2 Unless otherwise specified these data a...

Page 6: ... Receive the PAL Colour Bar signal Field strength 57 1 dBµV 75 ohms open 2 Connect the oscilloscope to TP210 as shown in Fig 4 3 Turn R216 to have the highest voltage 4 Turn R216 slowly in the opposite direction until the voltage goes down 0 1 V below the highest level 5 Adjust the signal level to 63 67 dBµV and make sure there is no noise 6 Now adjust the signal level to 90 95 dBµV and make sure ...

Page 7: ... About 100 About 100 4 pole magnet 6 pole magnet CRT neck Lacquer Purity magnet PURITY ADJUSTMENT No Adjusting point Adjusting procedure conditions Waveform and others Purity adjustment 1 Using the remote controller make the screen colour green only Adjustthecontrastcontroltohaveabeam current of about 700 µA 2 Degauss the cathode ray tube enough with the degaussing coil 3 Keep the purity magnet in...

Page 8: ...the P NORM mode 3 Turn on the service switch and select the Cut off background mode 4 Set the screen control to 0 10 position 5 Press the 9 key on the remote controller to reach the horizontal centering mode 6 Turn the screen control clockwise until the hori zontal raster of the first glimmering colour be comes slightly visible 7 Adjust the cut off data of the other two colours until the horizonta...

Page 9: ...ce Make sure the output is as specified 1 0 Vp p 3 dB 3 Terminate the audio output with a 10k ohm im pedance Make sure the output is as specified 1 76 Vp p 3 dB 1 Video and audio input check 1 Using the TV AV key on the remote controller make sure that the modes change in the order of TV AV and TV again and that the video and au dio outputs are according to the input and output terminals for each ...

Page 10: ...0 Bilingual Key 1 Receive Bilingual sound signal press the Bilin gual key Check whether there is change SOUND 1 to SOUND 2 9 Sharpness key 1 Receive the E 5CH signal 2 Select the sharpness on the P MODE screen 3 Check whether the Sharpness is OK or not with Up Down keys 6 PIC Normal key 1 Press the Normal key on the P MODE screen to make sure all the displayed items are at normal settings See belo...

Page 11: ... SETTING REMARKS CRITERIA 7 6 5 4 3 2 1 0 MEMORY MAP RH iX3031CEZZ SUB ADDRESS DATA FACTORY SETTING REMARKS CRITERIA 7 6 5 4 3 2 1 0 000 Initialization judgment data 23 Other than 23 23 001 Initialization judgment data 20 Other than 20 20 002 Initialization judgment data 13 Other than 13 13 003 Initialization judgment data 61 Other than 61 61 004 PLL data upper CH0 005 PLL data lower 006 PLL data ...

Page 12: ...er 0BE PLL data upper CH93 0BF PLL data lower SUB ADDRESS DATA FACTORY SETTING REMARKS CRITERIA 7 6 5 4 3 2 1 0 060 PLL data upper CH46 061 PLL data lower 062 PLL data upper CH47 063 PLL data lower 064 PLL data upper CH48 065 PLL data lower 066 PLL data upper CH49 067 PLL data lower 068 PLL data upper CH50 069 PLL data lower 06A PLL data upper CH51 06B PLL data lower 06C PLL data upper CH52 06D PL...

Page 13: ...r 0C8 PLL data upper CH98 0C9 PLL data lower 0CA PLL data upper CH99 0CB PLL data lower 0CC POWER TV AV 80 0CD BLUE BACKGROUND One digit two digit OFF Factory set at ON AA 0CE LANGUAGE 01 0CF LAST POSITION 01 0D0 LAST CONTRAST 3F 0D1 LAST COLOUR 1F 0D2 LAST BRIGHTNESS 1F 0D3 LAST TINT 1F 0D4 LAST SHARPNESS 1F 0D5 LAST VOLUME 00 0D6 LAST SERVICE MODE 00 0D7 0D8 0D9 0DA 0DB 0DC 0DD 0DE 0DF 0E0 CH7 C...

Page 14: ...1AB FAVORITE CH GREEN 20CH 14 1AC FAVORITE CH YELLOW 30CH 1E 1AD FAVORITE CH CYAN 40CH 28 1AE 1AF 1B0 1B1 1B2 1B3 1B4 1B5 1B6 1B7 1B8 1B9 1BA 1BB 1BC 1BD 1BE 1BF DATA SUB ADDRESS FACTORY SETTING REMARKS CRITERIA DATA 164 AUDIO SYSTEM 1 VIDEO SYSTEM 2 AUTO 00 165 166 167 168 169 16A 16B 16C 16D 16E 16F 170 CUT OFF R 0 00 171 CUT OFF G 0 00 172 CUT OFF B 0 00 173 DRIVE G 127 7F 174 DRIVE R 127 7F 17...

Page 15: ...26DN TU201 PLL N0004KJ 2s 0 5s Fig 1 TROUBLE SHOOTING TABLE Continued NO PICTURE NO SOUND YES YES YES Signal NO YES Noise NO NO Does noise or signal appear at pin 13 of IC201 NO SOUND No snow noise Does noise or signal appear at pin 21 of IC201 Noise increases but no signal is received Check the tuner supply voltage MB must be approx 9V BP must approx 5V BT must be approx 31V And CH preset data ch...

Page 16: ...AM PAL NTSC NO SPECIFIC COLOUR PAL NTSC SECAM NO COLOUR SYNCHRONIZATION NO YES YES NO Check IC801 R809 R810 R811 D801 D802 D803 Q801 Q802 Q803 Q804 and Q805 Check X801 C810 C815 C816 and R814 Check C901 and pin 31 of IC1001 TROUBLE SHOOTING TABLE Continued NEITHER VERTICAL NOR HORIZONTAL SYNCHRONIZATION CIRCUIT TO BE CHECKED Sync Separator Circuit NO VERTICAL SCAN Vertical linearity is abnormal Ch...

Page 17: ...20CT 250 17 CHASSIS LAYOUT 21CT 25 as is 6 5 4 3 2 1 A B C D E F G H ...

Page 18: ...1779CE 16 9 1 8 BA7357S 22 12 1 11 2SA1015 2SC1815 2SC1906 2SC2482 KiA7045P TA78L09 UPC78L05 iX0037CE 2SC3789 TA7348P BASE COLLECTOR EMITTER CATHODE ANODE BASE COLLECTOR EMITTER B C E B C E KA7809 KA7805 1 2 3 ANODE RED CATHODE COMMON ANODE GREEN 1 2 3 3 2 1 E C B TDA7056A iX0640CE PX0003PE 2SD1884 2SD2586 1 9 1 7 1 9 ...

Page 19: ...otherwise noted 3 All capacitors are µF unless otherwise noted P µµF 4 All capacitors are 50V unless otherwise noted VOLTAGE MEASUREMENT CONDITIONS 1 Voltage in parenthesis measured with no Signal 2 Voltages without parenthesis measured with 3mV B W or Colour Signal 3 All the voltages in each point are measured with VTVM WAVEFORM MEASUREMENT CONDITIONS 1 Colour bar generator signal of 1 5V peak to...

Page 20: ...20CT 250 20CT 250 12 11 10 9 8 7 6 5 4 3 2 1 A B C D E F G H 21 22 SCHEMATIC DIAGRAM ...

Page 21: ...20CT 250 20CT 250 12 11 10 9 8 7 6 5 4 3 2 1 A B C D E F G H 23 24 BLOCK DIAGRAM ...

Page 22: ... 11 10 9 8 7 6 5 4 3 2 1 A B C D E F G H 25 26 PRINTED WIRING BOARD ASSEMBLIES All the PWBs here are shown as viewed from their wiring sides PWB A Main Unit 21CT 25 as is K9398WE PWB B CRT Socket Unit 21CT 25 as is K9399WE ...

Page 23: ...AR IC801 VHiTB1226DN 1 R TB1226DN BB IC1001 RH iX3031CEZZ R M37221M4 110SP AW IC1002 VHiKiA7045P 1 R KIA7045P AD IC1003 VHiST24C04 1 R ST24C04CB6 AQ IC1004 VHiUPC78L05 4 R UPC78L05J AD TRANSISTORS Q201 VS2SC1906 1E R 2SC1906 AC Q202 VS2SC1906 1E R 2SC1906 AC Q203 VS2SC1906 1E R 2SC1906 AC Q205 VS2SC1815GW 1 R 2SC1815GW AB Q207 VS2SC1815GW 1 R 2SC1815GW AB Q301 VS2SC1815GW 1 R 2SC1815GW AB Q302 VS2...

Page 24: ...ZZ R Filter AD CF202 RFiLA0095CEZZ R Filter AE CF203 RFiLC0411CEZZ R Filter AE CF1001 RFiLA0084CEZZ R Filter AE L201 VP DF270K0000 R Peaking 27µH AB L202 VP DF270K0000 R Peaking 27µH AB L203 VP DF270K0000 R Peaking 27µH AB L204 VP XF1R0K0000 R Peaking 1µH AB L206 VP XF390K0000 R Peaking 39µH AB L401 VP CF101K0000 R Peaking 100µH AB L602 RCiLP0224CEZZ R Peaking Coil AE L605 VP DF101K0000 R Peaking ...

Page 25: ...AYK R 0 1 50V Mylar AB C504 VCCSPA2HL471K R 470p 500V Ceramic AB C505 RC QZA104TAYK R 0 1 50V Mylar AB C506 VCEAGA1EW108M R 1000 25V Electrolytic AD C507 VCEAGA1VW107M R 100 35V Electrolytic AC C509 RC QZA104TAYK R 0 1 50V Mylar AB C510 VCEAGA1VW477M R 470 35V Electrolytic AD C511 VCKYPA2HB102K R 1000p 500V Ceramic AA C512 VCFYSA1HB824J R 0 82 50V Mylar AC C513 VCFYSA1HB824J R 0 82 50V Mylar AC C5...

Page 26: ...0 6 3V Electrolytic AB C1017 VCKYPA1HF103Z R 0 01 50V Ceramic AA C1018 VCCCPA1HH680J R 68p 50V Ceramic AA C1019 VCCCPA1HH680J R 68p 50V Ceramic AA C1020 VCEAGA0JW107M R 100 6 3V Electrolytic AB C1021 VCCSPA1HL181J R 180p 50V Ceramic AA C1022 VCKYD41CY103N R 0 01 16V Ceramic AA C1023 VCKYD41CY103N R 0 01 16V Ceramic AA C1024 VCKYD41CY103N R 0 01 16V Ceramic AA C1025 VCKYD41CY103N R 0 01 16V Ceramic...

Page 27: ...D2HD820J R 82 1 2W Fuse Resistor AC R613 VRD RA2BE103J R 10k 1 8W Carbon AA R614 VRD RM2HD180J R 18 1 2W Carbon AA R617 VRS VV3AB330J R 33 1W Metal Oxide AA R618 VRD RM2HD102J R 1k 1 2W Carbon AA R619 VRD RA2BE393J R 39k 1 8W Carbon AA å R620 RR XZ0085CEZZ R 3 9 1 4W Fuse Resistor AC R621 VRN RV3AB1R5J R 1 5 1W Metal Film AA R622 VRD RM2HD223J R 22k 1 2W Carbon AA R623 VRD RA2EE683G R 68k 1 4W Car...

Page 28: ...Carbon AA R1045 VRD RM2HD180J R 18 1 2W Carbon AA R1046 VRD RM2HD180J R 18 1 2W Carbon AA R1047 VRD RA2BE472J R 4 7k 1 8W Carbon AA R1049 VRD RA2BE473J R 47k 1 8W Carbon AA R1050 VRD RA2BE473J R 47k 1 8W Carbon AA R1051 VRD RA2BE393J R 39k 1 8W Carbon AA R1052 VRD RA2BE272J R 2 7k 1 8W Carbon AA R1055 VRD RM2HD101J R 100 1 2W Carbon AA R1057 VRD RA2BE273J R 27k 1 8W Carbon AA R1058 VRD RA2BE822J R...

Page 29: ...W Metal Oxide AA R870 VRD RA2BE222J R 2 2k 1 8W Carbon AA R871 VRD RA2BE152J R 1 5k 1 8W Carbon AA R875 VRD RA2BE560J R 56 1 8W Carbon AA R876 VRD RA2BE560J R 56 1 8W Carbon AA R877 VRD RA2BE560J R 56 1 8W Carbon AA R898 VRD RM2HD272J R 2 7k 1 2W Carbon AA R899 VRD RM2HD272J R 2 7k 1 2W Carbon AA MISCELLANEOUS PARTS P851 QPLGN0441CEZZ R Plug 4 pin H AB P852 QPLGN0541CEZZ R Plug 5 pin K AB å SC851 ...

Page 30: ...publication may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise without prior written permission of the publisher SHARP CORPORATION AV Systems Group Quality Reliability Control Center Yaita Tochigi 329 2193 Japan TQ0000 S Aug 1998 Printed in Japan NA KG ...

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