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1.4. X-Radiation

Warning :

 1. The potential sources of X-Radiation in TV sets are the High Voltage section and the picture tube.

 2. When using a picture tube test rig for service, ensure that the rig is capable of handling 31.7kV without causing X-Radiation.

Note: It is important to use an accurate periodically calibrated high voltage meter.

 1. Set brightness to minimum.

 2. Measure the High Voltage. The meter reading should indicate 31.0 +0.7, -1.5 kV. If the meter indication is out of tolerance,

immediate service and correction is required to prevent the possibility of premature component failure.

 3. To prevent possibility of X-Radiation, it is essential to use the specified picture tube.

2 Location of Controls and Circuit Boards

Location and Function Name of Circuit Board
A - Main
T - Text
H - Rear Av

L - Crt Board
X - Pin Cushion
G - Power Board

4

TX-25P20T

Содержание TX-25P20T

Страница 1: ...ights reserved Unauthorized copying and distribution is a violation of law TX 25P20T MX 8A Chassis Colour 33 57 MHz PAL 33 6 MHz SECAM 34 42 MHz NTSC 33 75 MHz SECAM Receiving Stereo Sound System AV STEREO TEXT Video Audio Terminals AV 1 2 3 IN S Video Y 1 0V p p 75Ω DVD IN S Video C 0 3Vp p 75Ω Y PB PR Phone type Y 1 0 Vp p 75Ω PB PR 0 7 Vp p 75Ω Video 1 0 Vp p 75Ω Audio Approx 400mV 47KΩ Monitor...

Страница 2: ...ite Balance MARKET MODE CHK 3 11 6 G BOARDTNP4G120AK 13 6 1 A BOARDTNP4G104BM 14 7 H BOARDTNP4G131AC 15 8 X BOARDTNP4G108AQ 16 9 T BOARDTNP4G115AC 16 10 L BOARDTNP4G107AQ 17 11 Schematic Diagram for models TC 15PM10R MX 7 Chassis 18 12 SCHEMATIC 1 19 13 SCHEMATIC 2 20 14 SCHEMATIC 3 21 14 1 SCHEMATIC 4 22 14 2 SCHEMATIC 5 23 14 3 SCHEMATIC 6 LEFT HALF 24 14 4 SCHEMATIC 6 RIGHT HALF 25 14 5 EXPLODE...

Страница 3: ... being exposed to shock hazards 1 2 Leakage Current Cold Check 1 Unplug the AC cord and connect a jumper between the two prongs on the plug Fig 2 Fig 2 2 Turn on the receiver s power switch 3 Measure the resistance value with an ohmmeter between the jumper AC plug and each exposed metallic cabinet part on the receiver such as screw heads aerials connectors control shafts etc When the exposed metal...

Страница 4: ...h voltage meter 1 Set brightness to minimum 2 Measure the High Voltage The meter reading should indicate 31 0 0 7 1 5 kV If the meter indication is out of tolerance immediate service and correction is required to prevent the possibility of premature component failure 3 To prevent possibility of X Radiation it is essential to use the specified picture tube 2 Location of Controls and Circuit Boards ...

Страница 5: ...5 TX 25P20T ...

Страница 6: ...n 1 Remove 9 screws 2 Draw out Main Chassis 3 Stand the Main Chassis 4 Special Service Procedure 1 Self Check Function SELF CHECK is used to automatically check the Bus Lines and Option code of the TV set Contents of the SELF CHECK are as follows 6 TX 25P20T ...

Страница 7: ...et Mode Adjust VOLUME to zero and set OFF TIMER Button turn on the timer Then simultaneously press the RECALL Button on the remote control and the VOLUME DOWN Button on the TV set 2 Selection of CHK Mode Cursor moves to each CHK mode by pressing 1 or 2 of 10 key buttons on the remote control 1 Option Code Setting Mode CHK 1 If the memory IC IC1102 is replaced option code should be re memorized Opt...

Страница 8: ... 3FH 00H 3FH 00H 3FH 00H 3FH Note Picture will be changed to the one horizontal line by pressing 5 of 10 key buttons on the remote control no 1 5 4 White Balance Adjustment Mode To change the screen item in CHK mode press 3 or 4 of 10 key buttons Then Data and Level changes by pressing Volume or button Display Adj Range B DR R DR SUB BR BRIGHT B CUT G CUT R CUT 00H FFH 00H FFH 00H FFH 0 63 00H FFH...

Страница 9: ...ltage meter Electrostatic Type to an anode of the picture tube 3 Confirm that the high voltage is within the range of 31 0 0 7 kV Sub Contrast 1 Receive a colour bar pattern 2 Connect an oscilloscope to TPA41 3 Connect a short jumper between TPA57 TPA50 FBT pin3 TPA32 4 Set controls Picture menu Dynamic Normal 1 Adjust Bright Control a 2 3 0 2 Vp p 2 Adjust Sub Contrast Control b 2 8 0 1 Vp p PAL ...

Страница 10: ...ight controls and make sure that a uniform white field is obtained 10 Tighten the clamp screw Convergence 1 Apply a crosshatch pattern signal and set Contrast control to the maximum position 2 Adjust Brightness control to obtain a clear pattern 3 Adjust the Red and Blue line at the centre of the screen Fig 22 4 Adjust Red and Blue with Green line at centre of the screen by rotating RB G static con...

Страница 11: ...rizontal line on the screen 5 Return to full SCAN by pushing the position 5 key on the remote control 6 Adjust the R Drive and B Drive controls as to obtain uniform white on the white bar of the grey scale pattern 7 Confirm correct B W rendition and greyscale tracking or repeat CUT OFF and drive control set up Note Write down the original value for each address before adjusting anything 8 Wedge A ...

Страница 12: ...6 G BOARD TNP4G120AK TX 25P20T 13 ...

Страница 13: ...6 1 A BOARD TNP4G104BM TX 25P20T 14 ...

Страница 14: ...7 H BOARD TNP4G131AC 15 TX 25P20T ...

Страница 15: ...8 X BOARD TNP4G108AQ 9 T BOARD TNP4G115AC 16 TX 25P20T ...

Страница 16: ...10 L BOARD TNP4G107AQ 17 TX 25P20T ...

Страница 17: ...lowing Power Source AC 220V 50Hz Receiving Signal Colour Bar signal RF All customer s controls Maximum positions 7 Number in red circle indicates waveform number See waveform pattern table 8 When arrow mark is found connection is easily found from the direction of arrow 9 Indicates the major signal flow 10 This schematic diagram is the latest at the time of printing and subject to change without n...

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Страница 36: ...on E Electrolytic P Polyester Polypropylene T Tantalum C 0 25pF D 0 5pF F 1pF G 3 J 5 K 10 L 15 M 20 P 100 0 Z 80 20 Important Safety Notice Components identified by mark have special characteristics important for safety When replacing any of these components use manufacturer s specified parts Note Printed circuit board assembly with NLA is no longer available after production discontinuation of t...

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